Wearable Tech Unveiled

Stress is your body’s natural response to life’s peaks and crevices. It is defined as any real or interpreted threat to the physiological or psychological state of a person, resulting in physiological and behavioural responses. It is a reaction to an event or thought that adversely impacts your feelings and emotions.

While some stress is necessary and even healthy for our well-being, most forms of stress adversely impact the body and its functioning, especially if one is exposed to them for a prolonged period. Finding ways to deal with and manage stress is imperative to prevent serious health conditions, such as high blood pressure, heart disease, obesity and depression.

To truly understand and keep stress at bay, tracking it is the first step. Until recently, lab tests were considered the holy grail of determining the origins, levels and impacts of stress. However, there are now a number of technologies in the market that help you understand stress levels and mitigate them as much as possible. Let’s understand what these devices are and if they truly help reduce and manage stress.

Highlights

• Stress is defined as any real or interpreted threat to the physiological or psychological state of a person resulting in physiological and behavioural responses,
• Stress trackers are wearable devices that help track stress levels at various points in the day. The most critical component these devices use is your heart rate and heart rate variability (HRV),
• Studies have also found that there is little to no difference between the stress level results obtained from wearable devices and laboratory devices.

How Wearable Technology Works in Reducing Stress

Wearables have made massive strides in the way they track, measure and abate stress. From wrist monitors to headbands, wearable devices have advanced and changed the way they measure and manage stress.

There are two types of wearable devices that help with stress:

1. Stress trackers
   Stress trackers are wearable devices that help track stress levels at various points in the day. The most critical component these devices use is your heart rate and heart rate variability (HRV). So now, stress is not just a measure of beats per minute (heart rate), it is also a measurement of the time interval between heartbeats (heart rate variability).

If your BPM (beats per minute) is 60, it does not necessarily mean that your heart is beating at one beat per second. There is variation between each beat and this interval may vary vastly. For example, at 60 BPM, there may be 0.10 seconds between two beats and then 1.10 seconds between the following two beats.

A greater variability between heartbeats, or an HRV, is considered ideal. It reflects your body’s ability to endure stress or indicates that you’re recovering well from previously accumulated stress.

While accurate measurement of HRV is fairly difficult with wrist heart rate monitors, chest monitors may prove to be closest to the precise level of stress one may have experienced.

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Trackers should be worn at all times to give the most accurate data, including during rest and sleep. It should be noted that trackers are merely a representation of the level of stress endured at different points in the day.

They don’t ascertain the cause of such stress and neither do they help mitigate it.

To truly understand these variables, you will need to study the data the trackers collect, map it back to the cause and eventually reduce stress through methods only some trackers suggest.

However, catching your ups and downs in stress levels can prove to be important data, especially in moments of passive stress (when you are not aware that you are stressed, or when someone else’s stress passes onto you without your realising it).

2. Stress-relief devices

Devices that are focused on relaxation or stress relief come under this category. These devices are worn or placed on different parts of the body, such as the chest or the palms. They aim to circumvent stress using low-frequency sounds—or infrasound (less than 20 hertz)—accompanied by vibrations, thereby inducing relaxation.

Research has indicated that these vibrations can stimulate the vagus nerve, activating the parasympathetic nervous system and reducing the level of cortisol (the stress hormone) in the body, counteracting the effects of stress.

There is a range of stress-relief devices that experiment with different levels of vibrations or sounds, with some even adding thermal therapy (temperature control) acting as an aid to the vibrations to increase relaxation.

It should be noted that these devices aren’t a cure or a quick fix for stress. They help pivot your mind to a different and more relaxed front and are a great way to find methods of relaxation.

Latest Research Around Fitness Wearable Tech And Stress

Research indicates that HRV is currently the most accurate way to measure stress, especially in comparison to the average heart rate method (used to measure heart rate over a period of time and take the average of those readings) used earlier.

Studies have also found that there is little to no difference between the stress level results obtained from wearable devices and laboratory devices.

Since laboratory tests were considered more accurate and reliable, this study is a positive sign for wearables and their future. Wearable devices are non-invasive methods of testing stress.

However, contact between the body and the wearable device can sometimes be obstructed because of lack of contact with the skin, especially during sleep or movement, leading to less accurate and shorter durations of data received.

Trackers have now made people much more aware of their stress levels, leading to positive changes in the way people view, process and deal with stress.

A study conducted on veterans elucidated that sensors help them anticipate stressful events before they even occur, making their approach to dealing with stress more proactive.

The same study also revealed that people now had the time to develop coping mechanisms, keeping their stress at a minimum. In some cases, the devices have helped people sleep better and recognise the impact of sleep on their stress and vice versa.

What to look forward to in this space?

It is predicted that companies that make these sensors will try to use the data provided (such as stress levels and body battery levels) by these devices and make sense of it. Insights from this data will be tailor-made based on the wearer’s lifestyle and stress levels.

More companies are increasingly seeing the need for experimenting with wearable devices on other parts of the body, such as the ear and other areas that are closer to the heart, including chest monitors, and improving their accuracy. Another important feedback mechanism currently being explored is sweat and its components to both measure stress hormones and offer insights into emotional stresses.

Conclusion

Stress is an adverse reaction on the body or mind to any real or perceived threat. Prolonged exposure to stress can lead to chronic health issues, making tracking and relieving stress with the help of wearable devices imperative. Stress tracking and relieving devices help the body counteract stress and its effects.

Heart Rate Variability (HRV) is currently the most accurate way to measure stress used by most wearable stress trackers. It helps people preempt stressful events, develop coping mechanisms and improve sleep. The future of wearable technologies looks promising, with companies looking to improve data accuracy, provide actionable insights and experiment with wearable devices on different body parts.  

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new healthcare regimen including making any dietary or lifestyle changes.

References

1. Gender differences in stress response: Role of developmental and biological determinants – PMC
2. Stress and your health: MedlinePlus Medical Encyclopedia
3. The Best Wearable Stress-Relief Devices for Maximum Calm | Well+Good
4. A pilot study on high amplitude low frequency–music impulse stimulation as an add‐on treatment for depression – PMC
5. Stress wearables: best devices that monitor stress and how they work

Tracking steps is something everybody seems to be doing nowadays—on their phones, using a wearable device, you name it. It makes sense since keeping count of your steps makes a huge difference to your routine. It’s an extremely effective way to ensure you’re getting enough physical movement daily. Measurable benchmarks in fitness can help improve the overall quality of life.

You may work out regularly and never see the scale move, but when you track your steps, you realise that you’re only averaging 3,000 steps a day, which includes both exercise and non-exercise activities. This piece of information tells you that you need to move more and can allow you to set more focused goals for yourself.

You can incorporate more steps into your routine—taking the stairs instead of the elevator, doing outdoor activities like gardening, and walking to run errands on weekends are all great ways to ensure you get more steps in. Cardio exercises such as running, high knees, jumping jacks, etc., also boost your step count.

We’ve all read that sitting is as harmful as smoking. Sitting for over 8 hours a day has been linked to a 90% increased risk of type 2 diabetes. It’s important to break up prolonged sitting with movement breaks.

Step trackers can usually help in reminding you to get moving while allowing you to monitor how much you move. Trackers are a good way to meet your daily walking count. Setting and meeting daily goals is the perfect way to ensure you’re moving enough and monitoring your progress.

Trackers can also ensure personal and community accountability. Others can share their tips and triumphs on a community platform and make the whole endeavour more fun and supportive.

Trackers also help with incrementally increasing steps every day. Not moving much one day and walking 10,000 steps the next can be difficult, but it’s possible to add 100 steps with each passing day to your total count and create a walking routine that’s meaningful for your individual level of activity.

Highlights

• Step trackers can usually help in reminding you to get moving while allowing you to monitor how much you move,
• The way to break through a walking weight-loss plateau or hit a new step goal is to make changes to your routine, which can only be done by observing trends over a period of time,
• Walking to do errands instead of driving is a great way to get moving. This may take more time, but it adds movement to your day and allows you to be more conscious of your body and life in general.

Why Does Counting Your Daily Steps Matter?

A research team and investigators from three institutes from the National Institutes of Health, USA, studied the association between step count, risk of death and intensity of steps in a broad range of the U.S. population. They used data on physical activity from people aged 40 or older who wore an accelerometer—a device that measures step numbers and cadence (steps per minute) during their waking hours—for 7 days minimum between 2003–2006.

They then collected information on mortality in 2015, especially those from cancer and heart disease. They also tested whether step intensity, measured by the cadence, was associated with better health. There were 1165 deaths at the end of the study period, including 406 deaths from cardiovascular disease and 283 deaths from cancer.

The numbers showed that higher step counts were also associated with lower rates of death; these benefits were consistent across sex, age and race groups. The findings are also consistent with current recommendations that adults should move more and sit less through the day. Because this study is observational, it doesn’t prove that increased activity causes a reduced risk of death.

A higher step count may also include people who were in better health, to begin with, potentially influencing the results. Walking too little in a day may also cause exercise resistance, which means you don’t burn fat effectively, according to a recent study published in the journal Medicine and Science in Sports and Exercise.

The research determined that people who took 5,000 or fewer steps per day experienced exercise resistance, whereas people who walked more than 8,500 steps a day did not, which means that walking 8,500 steps a day is health-protective. Exercise resistance has a negative impact on triglyceride levels, which can negatively influence long-term heart health.

Researchers also studied data from 1,297 participants from clinical trials that randomly assigned half of them to track steps with pedometers over 12 weeks, while the other half didn’t track their steps at all. When they joined the trial, people took about 7,500 steps a day and got 90 minutes a week of moderate to vigorous workouts in at least 10-minute bouts. 3-4 years later, people who used pedometers were getting about 30 more minutes a week of moderate to vigorous physical activity, the study determined.

Pedometer users were also 44% less likely to experience a fracture and 66% less likely to have a serious cardiovascular event like a stroke or a heart attack. Tess Hariss, professor of primary care research at the St George’s University of London in the U.K., determined that increasing walking and maintaining it can reduce the risk of strokes, fractures and heart attacks over the next few years.

When they joined the pedometer trial, these people were in the age range of 45-75 and were typically overweight or obese. Most of them were non-smokers in good health without any history of diabetes, depression or cardiovascular disease. The people with pedometers appeared less prone to diabetes or depression by the end of the study; the difference between this group and the participants who didn’t track steps was too small to rule out the possibility that it was due to chance entirely.

Additionally, the trial participants did get help in setting realistic walking goals, received coaching from nurses and were encouraged to keep step diaries. Dr Mitesh Patel, director of the Penn Medicine Nudge Unit at the University of Pennsylvania, Philadelphia, says that tracking daily activity with a pedometer—wearable or smartphone—is an important part of any physical activity programme.

It also needs to be combined with behavioural change strategies via coaching, goal-setting and social interventions to make them more sustainable. The limitations of the study were that the researchers lacked four years of data pertaining to some participants and that most of the participants were white and female, making it possible that the results of such a study might be different in other populations.

What Are The Benefits of Tracking Your Steps?

There are numerous benefits of counting your steps:

1. Enables you to beat a fitness plateau A fitness plateau can be a very frustrating experience for people who’re trying to lose weight. Walking and assessing your food choices help you beat the plateau. Tracking your steps can also help you make suitable adjustments. The way to break through a walking weight-loss plateau or hit a new step goal is to make changes to the routine, which can only be done by observing trends over a period of time. Looking at long-term trends is also more beneficial in comparison to looking at daily numbers since your step count may fluctuate based on external factors. A few days of fewer steps is not a reason to panic, but a few weeks of consistently lower step counts means that something’s changed for the worse. With enough data, you can look for trends like steps being higher on weekends or weekdays and even times of the day when you’re more or less active. It may also be the case that your step goals are too high; not everyone has the stamina to walk an hour every day, for example. When you’re far off from your ultimate goal, it’s better to set a smaller goal to hit first. Setting a goal you can’t hit is likely to hurt your walking motivation, so use your data to inform the best step goal for you.
2. Holds you accountable: Staying on track with fitness goals is made much easier when there’s a sense of accountability. By simply tracking your steps, you may feel the need to move every day no matter what. Skipping your morning run, for example, will reflect in your daily step count, and seeing that decrease will allow you to acknowledge the decision you made. Additionally, tracking steps can allow you to support and receive support from friends, co-workers or family members. As mentioned, community support is always beneficial for weight loss and fitness improvements.
3. Reminds you of your progress: There are going to be times in your fitness journey when you may judge yourself for not achieving the goals within the time frame you set for yourself. It’s also easy to forget past successes when you face a new challenge. Keeping a record of your daily steps helps you appreciate your progress and how far you’ve come. Reminders of your accomplishments, such as completing 13,000 steps on an afternoon hike with your friends, trigger positive feelings and a sense of confidence. Looking back on previous wins is always helpful, especially when you need a boost.
4. Helps keep track of other associated health goals: Evidence suggests that walking positively affects general fitness and mood and positively affects weight management, BMI and waist circumference. It also helps maintain and improve sleep quality since being active during the day helps you sleep better at night. A decreased risk of hypertension reduces the risk of cardiovascular strokes and type 2 diabetes while also reducing stress. Walking was observed to improve the quality of life for depressed middle-aged women who reported feeling more sociable and energised after walking. Taking a walk during your lunch hour can significantly impact your mood and help reduce work-related stress. It can also help slow down mental decline while strengthening complex thought and decision-making.

How To Increase Your Step Count With Time?

You might start with a more conservative goal, but increasing and improving your daily step count over time is easy. Some easy ways to achieve that are:

1. Depending on your step tracker: Regularly using your step tracker will enable you to stay accountable. Realising you’ve only done 1,000 steps in one day may give you the extra motivation you need to make up for it the next day,
2. Walk between errands: Walking to do errands instead of driving is a great idea. This may take more time, but it adds movement to your day and allows you to be more conscious of your body and life in general,
3. Walk for your commute: If it’s possible, try incorporating walking into your commute. If you’re driving to work or taking public transport, and if you’re limited by terrain or ability, you can attempt to devote part of the way to walking. If you’re taking public transport, walk to one bus/metro stop further than yours, or get off a few stops early to walk the rest of the way,
4. Get a walking buddy: Having a buddy to stroll with keeps you accountable and moving and gives you company. Additionally, the social connection has profound mental and physical benefits as well,
5. Add steps into the work day: If you’re sitting at your desk a lot, try moving around between calls or sending emails. You can even set hourly reminders on your phone that’ll remind you to move, 
6. Mini movements: Stand or pace while taking phone calls, or stretch your arms overhead and march in place, 
7. Arriving early at meetings? Do this: Don’t just sit and scroll through your phone if you arrive early for appointments. Instead, use the extra minutes to get a small walk in, 
8. Walk around stores: While grocery shopping or in the mall, walk around the space a little before you start shopping. You can also walk up and down every single aisle at the grocery store, 
9. Build the habit slowly: Build the habit in incremental steps. Adding 1,000 steps a day to your step count is more manageable than adding 5,000 steps. Increasing the amount of physical activity or steps over a long period of time reduces the risk of injury and helps create lasting behavioural change, 
10. Include both long and short walks: One long walk a day sounds ideal, but several short walks a day can help equally. Going on mini-walks is also a great way to boost your daily step count.

Conclusion

Walking is undoubtedly one of the best ways to maintain your fitness levels and health. However, incorporating a walk into a busy lifestyle is tough. This is where step trackers come into play. Tracking your steps helps you beat a potential fitness plateau, holds you accountable, reminds you of your progress and helps you keep track of other associated health goals.

There are a number of ways to improve your step count with time, such as walking between errands, walking for your commute, getting a walking buddy, adding steps into your work day, taking multiple trips while running errands, mini-movements, walking around stores, building the habit slowly and including both long and short walks, among other things.

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.

References

1. Tracking Your Activity and Steps: And Why It’s Important
2. Benefits of a step tracker
3. Health benefits of walking and higher step counts
4. Daily Step Count and Postprandial Fat Metabolism
5. Yes, counting steps might make you healthier

Unless you’ve been living under a rock for the past decade, the emergence of wearable tech should not be an alien concept. Wearable smart devices have evolved and now monitor everything—from your activity during the day to those precious z’s at night. Sleep is essential to our physical and mental well-being; our bodies use this time to repair and rejuvenate cells and clear toxins away.

Let’s look beneath the surface and explore the essential function of sleep and the activities that take place in our bodies during slumber. Then, let’s delve into wearable tech in healthcare the science behind the latest devices and the advancements in sleep tracking.

Highlights

• Our sleep-wake cycle is controlled by our circadian rhythm, an internal biological clock that interprets the environment and controls hormone release to dictate our behaviour,
• Wearable technology uses sensors to track important parameters in individuals while they sleep—such as heart rate and blood oxygen(O2) levels,
• There are two potential drawbacks of wearables—lack of standardisation of metrics and accuracy compared to the gold-standard PSG sleep test.

The Science of Sleep: What Happens to Your Body When You Sleep

Sleep is a vital biological function known to be correlated to human health and performance, but the inner workings of the body, while we sleep, have not been fully understood yet. We sleep for a third of our day (ideally), during which several biological processes occur in our bodies: cellular restoration—whereby our cells and muscles repair themselves—protein synthesis and tissue growth.

Our glymphatic system—responsible for the distribution of compounds and eliminating waste throughout the brain—comes alive when we sleep. It eliminates toxic byproducts such as soluble proteins and metabolites (end product of metabolism) that accumulate in the brain, gearing us up for the next day. Sleep is known to play an integral role in our metabolism and a lack of sleep wreaks havoc on our systems.

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Two Biological Mechanisms Control our Sleep-Wake Cycle

1. The Circadian rhythm
2. Homeostasis

1. Circadian rhythms

Our 24-hour internal biological clock, control metabolism and hormone release. Environmental changes, such as temperature and light, trigger appropriate responses—they keep us alert during the day and sleepy at night. Our tissues and systems (endocrine, digestive, etc.) have secondary internal clocks—or ‘peripheral oscillators’—which send messages to the brain that help trigger our sleep-wake cycle.

Circadian rhythms modulate the release of numerous hormones, including:

1. Melatonin is the hormone that induces sleep.
2. Cortisol, the stress hormone, decreases while we sleep at night and peaks just after we wake up.
3. The growth hormone, released by the pituitary gland, helps cells in our bodies repair and grow while we’re asleep.
4. Antidiuretic hormone, which switches off the need to urinate during the night.
5. Proteins called cytokines are released by our immune system, which helps prevent inflammation.

The next time you binge-watch Netflix late into the night, snacking on your favourite munchies, know that you might be throwing your circadian rhythm out of whack.

Blue light from the screen tells your body that it is not time to go to bed, causing an increase in heart rate. Moreover, you need to digest your food properly before the stomach calls it a day.

As a result of doing all this extra work, your body takes longer to cool down to an appropriate temperature to get some sleep (a couple of degrees below normal).

2. Homeostasis

A state of internal equilibrium, tracks our need for sleep, regulates its intensity and reminds our bodies to get some solid sack time. Our ‘sleep drive’ or desire to sleep, increases the longer we are awake and is linked to the release of adenosine.

Adenosine is a neurotransmitter that inhibits brain processes associated with being alert and awake. It is also a natural painkiller and regulates our heart rhythm. Adenosine levels in our bodies gradually increase throughout the day and peak at bedtime, prompting sleepiness.

What are the 4 cycles of Sleep?

When we nod off, a series of stages—four, to be precise—puts us into a deep sleep, characterized by changes throughout the body. They are:

1. Non-rapid Eye Movement
2. Light Sleep
3. Deep Sleep
4. REM – Rapid Eye Movement

Each cycle (from stage I to IV) lasts around 90 minutes. If awoken after a completed cycle, one is more refreshed than if awoken during it.

Neurological Brain Activity While Asleep

What transpires in our brains while we sleep? Various regions are surprisingly active during the four stages:

1. Within the hypothalamus lie clusters of cells called the suprachiasmatic nucleus (SCN), the control centre of our circadian rhythm.
2. In low light, the pineal gland produces melatonin and distributes it through the bloodstream and cerebrospinal fluid.
3. The basal forebrain releases adenosine, which increases sleep drive.
4. The brain stem (pons, medulla and midbrain) controls transitions between wake and sleep. It communicates with the hypothalamus and other regions of the brain.
5. The thalamus is a region that relays sensory information to our brain. It is inactive during the first three stages but becomes active during REM sleep.
6. The thalamus communicates with the cerebral cortex, the covering of the brain responsible for processing and interpreting information, learning and memory. The thalamus sends images, sounds and other sensations to the cerebral cortex when we are dreaming.
7. When we fall into REM sleep, the amygdala becomes active, helping us process emotions while we dream. Dreaming occurs for approximately two hours each night and is most vivid during REM sleep.

An effective way of tracking brain activity during sleep is by measuring the frequency of brainwaves (in Hertz or Hz). Brainwaves are measured using an electroencephalogram (EEG), which helped researchers categorise sleep into the four distinct stages we understand today. When we are awake and alert, our brainwaves operate at gamma, a frequency between 12 and 35 Hz.

In stage N1, brainwaves are smaller and more uniform (than gamma) and slow to a frequency between alpha (8-12 Hz) and theta (4-8 Hz).

During N2, brain waves continue to slow, but are prone to occasional bursts of rapid waves, dubbed sleep spindles. As our bodies enter the deep, restorative state of N3, brain waves slow to delta, a frequency between 0.5 and 4 Hz. If we don’t get enough sleep with delta waves, it leads to an inability to rejuvenate the body and revitalise the brain.

When we enter REM sleep, our brainwaves suddenly spike in frequency (to gamma levels) as if we are awake. This suggests heightened activity in our central nervous system and is thought to play an important role in information processing and memory creation.

The Science Behind Fitness Wearable Tech

Referred to as the gold standard for studying sleep, polysomnography (PSG) continues to be the benchmark for sleep evaluation. A comprehensive test that monitors an individual’s brain waves (EEG), blood O2 level, resting heart rate, muscle activity and breathing, it is used to diagnose sleep disorders. However, PSG is an expensive and cumbersome clinical study, not feasible for the masses.

The advent of several sleep-sensing technologies has changed the landscape of studying sleep, the ultimate goal being continuous sleep monitoring. Manufacturers are making sensors more accurate, smaller, and less intrusive for the user.

Technologies include bed sensors, mobile health, radio frequency (RF) sensors, ultrasound, wireless EEG, and smartwatches or wearable tech. Sleep measurement devices can now monitor peoples’ brain waves, oxygen level, circadian rhythms, heart rate, respiratory rate, and body temperature.

A study by Pozuelo et al charted the accuracy versus usability (user burden) of sleep measurement devices, and it emerged that wearable devices and bed sensors offer the least user burden with moderately high accuracy (PSG has higher accuracy but with a much higher burden on the user).

Researchers compared devices across a range of metrics, including their measurement of sleep time, quality, and stage. They also evaluated the technology based on its scalability and usability (user burden).

Wearable tech emerged as a fairly accurate solution to collect data en masse. In an age where data is king, researchers can effortlessly collect user data across long time periods for a wide demographic (called free-living studies).

Data begins its life in a clinical study or from your wearable device. Once it is stored and uploaded to a server, processed, cleaned, and modelled, it has an abundance of applications.

Apart from use in longitudinal (observational, long time-period) studies and research, this data has numerous uses in the health and wellness industry. Doctors and nurses can make recommendations based on a patient’s past data and consumers may benefit from lifestyle recommendations after their devices notice trends in their behaviour.

Insurance and pharmaceutical companies can view client data to monitor how their clients are doing and whether any adjustments need to be made.

As with any emerging technology, challenges remain. For one, there is no standardisation across products—no defined or accepted guidelines for this plethora of products to adhere to.

There is an inherent lack of technical information disclosed by companies, such as sensor accuracy and algorithms used, which is somewhat understandable, given that these are trade secrets or intellectual property of the companies themselves.

However, it does not provide an apples-to-apples comparison and therein lies the problem.

Secondly, the reliability of data must come into question. Is the metric being captured accurately? Will the devices exhaustively capture all important data?

How does wearable tech track your sleep?

So how do these wearable devices accurately track our sleeping habits? What technology is at play?

Wearable technology is any electronic device worn on a user’s body and includes medical devices, accessories, jewellery, and clothing. Devices are equipped with a combination of sensors, each with its own function. 

Actigraphy

Actigraphy, most commonly used in healthcare wearable technology, is a validated method of study that uses monitors on the wrist or ankle to record the acceleration or deceleration of body movements or sleep disorders.

Actigraphy relies on accelerometers which, as the name suggests, are sensors that measure the acceleration of a body or structure.

Accelerometers

Accelerometers use movement data to make predictions of the time spent asleep versus awake and the current sleep stage. A device that measures the vibration, or acceleration of motion of a structure.

Sensors track basic human movements such as body orientation, tilt, incline and rate of speed change (of the body) throughout the day.

Actigraphy and accelerometry both have potential drawbacks, including a lack of standardisation of human activity recognition (for example, device A may have a different reading than device B for the same activity) and a lack of assessment techniques for sleep during the day.

Smartwatches and wearable devices use a combination of actigraphy and heart rate monitors to derive their metrics. These metrics are displayed on an accompanying smartphone app, where users can view their historical data.

Henriksen et al. conducted a study of 423 fitness trackers and smartwatches released from 2011 to 2017, each equipped with different sensors, algorithms and mobile apps for viewing and analysing data. They noticed that sensor support improved every year and that the most common sensors found were the accelerometer and the photoplethysmogram (used to estimate heart rate). Photoplethysmography uses light to track blood flow volume changes.

To track sleep, a host of other sensors have made their way into wearable devices, such as BP monitors, mini ECGs and pulse oximeters. ECG sensors use electrodes to detect small electrical impulses emitted with each heartbeat.

Due to COVID-19, we are no strangers to pulse-oximeters—they measure our blood oxygen levels with fair accuracy. Mobile phones use a combination of gyroscopes, accelerometers and microphones to chart our movement while asleep.

Gyroscopes

Gyroscopes follow the principle of conservation of angular momentum to measure angular velocity and are used in compasses, aircraft and ships to detect the deviation of an object from its intended orientation.

Gyroscopes detect our body orientation and rotation while we sleep.

The caveat with using mobile phones to track sleep, however, is that the device must be in close proximity to the user to be able to measure sleep metrics.

It is important to note that while assessing data, one must be careful of ‘noise’ or extraneous data. Aggregating sleep data from various sources (i.e., more than one device) may solve this by making models more robust and tolerant to ‘noise’ and/or missing data.

Rings, which are one of many types of sleep trackers, can track pulse rate, a variation on inter-beat intervals (IBIs) and pulse amplitude. A study conducted by Zambotti et al compared one of the ring models to traditional PSG. Although the model detected some stages of sleep with unerring accuracy, in other states the results were mixed, indicating that the field has some way to go to replicate results from a PSG.

Reader, beware. In some cases, adopters of wearable sleep monitors suffer from orthosomnia, a condition where users suffer poor quality sleep because they are worried about achieving a high ‘sleep score.’ In these instances, individuals must improve their sleep hygiene to achieve better sleep.

Conclusion

Sleep is as vital to our bodies as sustenance; a lack of sleep increases our risk of cardiovascular disease, obesity, high blood pressure and diabetes. Our circadian rhythm is a 24-hour biological clock that dictates when we go to bed. However, all the biological processes that underpin sleep have not been fully explored. To date, the most accurate method of studying sleep is polysomnography (PSG), which has enabled us to identify its four distinct stages. Our systems behave distinctly during sleep, identified by parameters such as heart rate, respiratory rate and movement.

Enter wearable devices, an unobtrusive method of measuring sleep across a wide range of demographics and over a long period of time. As an emerging technology, there is a gulf in accuracy when comparing wearables to PSG testing (which is more comprehensive and expensive). Companies use different sensors such as accelerometers and photoplethysmograms to measure everything from movement to heart rate. They then create their own algorithms to determine sleep metrics for individuals, leading to a lack of standardisation across devices in the industry. If companies share raw data, it serves to fuel further research in the field and has a host of end-user applications in the health and wellness space.

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.

References

1. The Glymphatic System: A beginner’s Guide
2. Brain Basics: Understanding Sleep
3. What Happens When You Sleep? | WebMD
4. Brain Activity During Sleep
5. Brain Waves – an overview | ScienceDirect Topics

When it comes to building an optimal workout routine, the chances of an all-encompassing model are slim to none. Age, level of activity, body type and the general demand from your body—all play a crucial role in determining what your optimal workout routine will look like.

Each workout is designed to load muscles (put a certain amount of stress on them), subsequently breaking them down to increase strength and endurance. For this to happen, muscles require ample rest and recovery.

According to Medical News Today, a person should have at least one rest day every 7-10 days when exercising regularly. The absence of proper rest and recovery could not only negate the benefits of your workout but also adversely impact your muscles.

One way to understand your recovery process better and track it is to use a wearable tech device. Let’s understand how rest and recovery play a role in building a workout routine and how a wearable might help.

Highlights

• Rest allows the body to adapt to the stress-induced during the workout, replenishing the depleted glycogen (stored energy) and repairing the body’s tissues,
• Studies show that the muscles need anywhere between 48-72 hours of recovery time before working for the same muscle group again,
• From tracking your glucose to checking energy levels to tracking your heart rate and its variability, all of these devices have one ultimate aim—to enhance performance by tracking different parameters such as sleep, energy, heart rate and activity levels.

The Principles of Rest and Recovery

Rest allows the body to adapt to the stress-induced during the workout, replenishing the depleted glycogen (stored energy) and repairing the body’s tissue. Since glycogen synthesis is a slow process, ample rest and recovery in the form of food, sleep and active recovery play a crucial role in determining training load and reducing risks associated with less rest.

Determining training load (the volume and intensity of the training) and the rest and recovery required can be difficult. The general practice to prevent the negation of the benefits of your workouts involves scheduling two types of rest and recovery in your overall training programme.

Two Types of Rest and Recovery

1. Active or short-term recovery

Active or short-term recovery is any low-intensity exercise done in a short amount of time after an intense workout. It involves using a different set of muscle groups and keeping the heart rate elevated.

Active recovery increases blood circulation in the body, removes accumulated metabolic waste in the muscles post an intense activity and supplies nutrients to broken down muscles to repair and build them.

Walking, jogging, swimming, yoga and cycling are all examples of active recovery. Sleep and food are also useful aids for speedy muscle recovery.

2. Passive or long-term recovery

Long-term recovery is when there are scheduled seasonal rest and recovery days or even weeks. It usually implies little to no physical activity for this period to allow the body to completely recover before resuming training.

These generally include massages, foam rolling, sauna sessions, contrast showers (hot and cold showers) and sleep to help the muscles decrease lactate levels to avoid cramps and heal soreness.

Training load and fitness goals determine the exact number of active and passive recovery days required to ensure the body recovers before breaking the muscles down again.

Why Rest Days are Important in Fitness Traning

A myriad of scientific and anecdotal evidence highlights the importance of a tailored recovery programme as a part of your workout regime. Exercising imposes an intense level of physiological stress on the body, forcing the body to adapt and regain hemostasis (balance).

However, the body cannot sustain this physiological stress for prolonged periods without adequate recovery.

Over time, inadequate rest crops up in the body in the form of increased injury, a compromised immune system and overtraining. Therefore, structuring your recovery is just as imperative as the rest of your routine because it:

1. Reduces injuries

A repetitive load on the muscles can strain them by causing microscopic tears in your muscle tissue. These tears lead to pain and stiffness in the muscles and without adequate recovery, injuries are bound to happen. A proper recovery process including stretching, supplementation, hydration and sleep can help the muscles become resilient.

2. Prevents overtraining

The goal of training is to improve performance by loading the body with measured and timely increments. The frequency, volume and intensity of the training when offset with a carefully designed recovery programme can help prevent overtraining, fatigue, illness and injury.

3. Promotes relaxation and improves performance

The mind is a critical component of any training programme. In addition to the body, the mind also takes on a lot of the training load. Taking active or passive rest days not only helps the body but also the mind recover faster, ensuring training days are more efficient. Time off from the routine also ensures higher motivation levels and less fatigue, leading to greater efficiency in training and training load increments.

4. Prevents fatigue and promotes muscle recovery

Physiological stress imposed on the muscles not only breaks the muscles down but also depletes the glycogen (stored energy) present in them. When this source is depleted, the muscles tend to become fatigued and sore. Replenishing the glycogen requires adequate rest and recovery.

5. Increases strength and endurance

During the rest phase, cells called fibroblasts work on healing the microscopic tears caused during a workout. These cells help the tissue repair and grow, ultimately building muscle growth, strength and endurance.

How Does Wearable Technology in Healthcare Track Physical Activity?

Studies show that the muscles need anywhere between 48-72 hours of recovery time before working for the same muscle group again. For example, if you’ve worked your chest muscles, you cannot work on them again for another 48-72 hours.

Each individual requires a different training load, subsequently requiring varied periods of rest. To understand the exact time required for recovery, accurate data acquired from wearable devices can prove to be a helpful tool.

In Fitness Wearable technologies track, collect and transmit data from the human body to external devices via sensors attached to the body. Information is tracked in real-time, and all relevant data points are utilized by the devices to make sense of this information. These sensors can be present anywhere on the body, such as the wrist, fingers, chest or arm.

Smartwatches, wearable tech rings, heart rate monitors, and Continuous Glucose Monitoring (CGM) devices are some of the many available devices on the market.

From tracking your glucose and checking energy levels to tracking your heart rate and its variability, all of these devices have one ultimate aim—to enhance performance by tracking different parameters such as sleep, energy, heart rate and activity levels.

Although the need for wearable technology is highly debated, there are a few ways that wearable technology has become an integral part of activity tracking and, as a result, contributes to overall health:

1. Monitoring Progress

Simple wearable technology can be a catalyst to monitoring and improving health more proactively. These technologies help understand the current state of the body and its reaction to physical activity and help track improvements thereafter.

For instance, tracking your walk can help increase your walk from 1 km a day to 1.5 km in the subsequent week. This simple measurement increases accountability, improves health and leads to progress.

2. Data-Backed Training Programs

Improvements in training become a lot easier when you have a benchmark to see how your body is doing. Having a basic understanding of your heart rate, SpO2 (level of oxygen present in the blood) levels or even your glucose levels during, before and after your physical activity can help you understand your body more, leading to better gains.

Tracking activity also makes it easy to understand the exact amount of rest needed to prevent injuries and soreness. Training becomes a product of mathematics instead of a random process and increments, deloading (taking short, measured breaks from workouts) and reloading (a period of lower volume and intensity in workouts) become a lot easier.

3. Preventing a Sedentary Lifestyle and Improving Public Health

Most wearable technology has been used to improve health. Simple tracking of sleep, food, water, stress and fatigue can help improve overall health and well-being. Evidence suggests that higher volumes of physical activity tracked on wearable devices were associated with a lower mortality rate, and high-intensity workouts helped reduce the mortality rate further compared to low-intensity workouts.

Wearable technology has helped a whole segment of the population increase their levels of activity and motivation and, subsequently, has improved their health. Monitoring vital signs along with daily activity levels improves overall accountability and health. It gives users a measure of their basic activity levels and keeps them motivated to push a step further without causing any damage.

Accuracy of Wearable Technology in HRV & Sleep Tracking

There have been a lot of debates around the accuracy and relevance of wearable technology. Although wearable technology has a high measurement accuracy for heart rate, heart rate variability, steps and distance, sleep tracking has been a grey area.

Despite the prevalence of sleep issues and the wide availability of sleep trackers, research on the efficacy of these trackers is scarce.

Several studies indicate that sleep trackers are only 78% accurate in measuring sleep and wake cycles, especially REM cycles (deep sleep cycles).

Since sleep trackers are worn on the wrist or fingers, their estimates about sleep and sleep stages are made based on body movement and heart rate data.

They may fail to account for rapid eye movement, brainwave activity and multiple other parameters associated with deep, well-rested sleep, making it difficult to rely on them for proper rest and recovery.

Conclusion

Optimal training and workout routines always include a proper rest and recovery programme, mostly every 7-10 days. Rest days can either be active and/or passive, depending on the training goals and the training load. Without a proper recovery plan, chances of injury, overtraining and compromised immunity are higher.

Wearable devices help track physical activity, making tracking progress easier, preventing a sedentary lifestyle and designing evidence-based programmes. However, tracking activity through wearable devices may not always give the most accurate data points, especially concerning sleep tracking and calories consumed.

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new healthcare regimen including making any dietary or lifestyle changes.

References

1. Regulation of Muscle Glycogen Repletion, Muscle Protein Synthesis and Repair Following Exercise – PMC.
2. Rest and recovery are critical for an athlete’s physiological and psychological well-being.
3. What Is Passive Recovery? Benefits & Techniques – Massage Gun Fight.
4. Effects of Different Between Test Rest Intervals in Reproducibility of the 10-Repetition Maximum Load Test: A Pilot Study with Recreationally Resistance Trained Men – PMC
5. Recovery and injury prevention: the science behind human resilience – The Turmeric Co