Everybody knows that sleep is important to health and overall fitness, but we still tend to discount it. In a highly competitive and productivity-oriented culture, sleep is often looked at as a luxury that we can delay or catch up on later.
But while this may be possible for short periods, it can lead to a number of health problems over time. Most adults are recommended an average of seven to nine hours of sleep per night, but nearly two in three adults in the US report getting less than this.
But more than just tiredness or fatigue, sleep deprivation has been linked to a number of other health problems. The most significant amongst these is cardiovascular health and its associated conditions. Sufficient sleep is just as important as following the right diet or exercise plan in terms of keeping your heart healthy.
But how does this work, and how are these factors connected? Examining different aspects of how sleep or lack of sleep can impact health, one can be more aware of the need for a consistent eight hours and the physiological factors at work.
Highlights
- Heart problems are a leading cause of illness and mortality around the world, and there is a growing recognition that sleep deprivation is tied to heart health,
- Sleep provides time for the body to refuel and plays a key role in nearly every aspect of the health and system of the body,
- A number of observational studies have shown strong correlations between sleep deprivation, insomnia, daytime sleepiness, snoring and a higher risk of heart failure.
How does poor sleep affect your heart health?
For most adults, getting seven to eight hours of shut-eye a night is important and has been linked to a healthier heart. Though the ways in which sleep can affect the heart are numerous, the link with coronary arteries is still being studied. What is clear, however, is how lack of sleep is tied to a number of conditions and increases the risk of many other factors responsible for heart health and overall well-being.
As an organ responsible for pumping blood to the body, the heart and circulatory system ensure that all the rest of our organs and tissues get a sufficient supply of oxygen. Heart problems are a leading cause of illness and mortality around the world, and there is a growing recognition that sleep deprivation is tied to heart health in a similar way that factors like poor diet, lack of exercise and smoking are.
Sleep provides time for the body to refuel and plays a key role in nearly every aspect of the health and system of the body. People with chronic sleep disturbances or deprivation and conditions such as insomnia or sleep apnea have been shown to have a shorter life expectancy than those who consistently sleep enough. Similarly, people with consistent sleep deprivation were shown to be more likely to suffer from heart disease, strokes, diabetes or various other conditions.
The American Heart Association reported that a lack of sleep is linked to a higher build-up of calcium in the arteries. This can lead to plaques which increase the risk of a heart attack. Even just one or two hours of less sleep than usual each night increased this build-up significantly. Poor sleep quality or insufficient sleep can also lead to problems with blood pressure, mood disorders, weight management, asthma, and other conditions. Conversely, getting good sleep may help reduce or reverse damage to the cardiovascular system and should be an essential part of a healthy lifestyle.
The connections between poor sleep and heart rate
The major function of sleep is to allow the body to rest and recover, and the different stages of sleep serve different purposes in this process. These stages reduce stress on the heart and give it time to recuperate—a process that does not properly occur if sleep is frequently interrupted or insufficient.
Within about five minutes of falling asleep, the heart rate gradually slows to around its resting rate (beats per minute at rest), the body temperature reduces slightly, breathing stabilizes, and the muscles relax. These changes remain in place for a couple of hours or more until the next phase of deep non-rapid-eye-movement (NREM) sleep, during which blood pressure falls and the heart rate slows to approximately 20 or 30% less than the resting heart rate.
These deep stages of sleep are essential to heart health. But when sleep deprivation is chronic, an individual may not spend enough time in deep NREM sleep, and over time this can lead to a number of health problems linked to cardiovascular functioning. Below, we examine a few ways in which a lack of sleep or poor sleep can impact bodily functioning and systems tied to heart health.
Sleep and Blood Pressure
During normal, healthy sleep, a phenomenon called nocturnal dipping leads to your blood pressure dropping by about 10 or 20%. Research suggests that this is an important aspect of heart health. When there is chronic sleep deprivation or interruptions to sleep, blood pressure doesn’t dip, and this has been tied to increased hypertension and a higher risk of strokes or heart attacks. Other studies have also linked sleep deprivation to higher daytime and overall blood pressure, particularly in middle-aged adults.
Sleep and heart failure or cardiovascular health
Atherosclerosis is known as the buildup of plaque in the arteries due to inflammation, calcium, or the hardening of the artery walls. It has been linked to poor sleep or sleep deprivation, which can strain the arteries and contribute to speeding up this process. As it also contributes to higher blood pressure, lack of sleep is also linked to heart failure and heart attacks.
A number of observational studies have shown strong correlations between sleep deprivation, insomnia, daytime sleepiness, snoring and a higher risk of heart failure. People with two or more symptoms were at a higher risk. Similarly, other studies have also suggested that people who regularly sleep less than six hours each night are at higher risk for heart attacks. This is due to insufficient sleep, frequent sleep disruptions that throw off the balance of the different sleep stages, and also to hypertension or atherosclerosis.
Similar results have also been reported in the case of strokes—when the blood flow to the brain gets cut off due to plaque or a blood clot from an artery. Many studies have shown a high correlation between sleep deprivation and a greater likelihood of a stroke or mini-stroke.
Sleep and obesity
Another factor which can play a role in heart health and is closely related to sleep quality is weight or obesity. Not getting sufficient sleep can lead to weight gain or even obesity because sleep has been linked to the regulation of hormones like leptin and ghrelin, which control appetite and regulate metabolism. Studies have shown that too little sleep leads to a rise in ghrelin, greater cravings for food, and increased consumption of sugary or unhealthy snacks in order to combat tiredness.
It seems intuitive that tiredness would reduce the likelihood of regular exercise and lead to poor diet choices. This is linked to hormonal balance and can lead to weight gain or even obesity over the long term. Observational studies have found that people who sleep less than seven hours a night are more likely to have a higher body-mass index (BMI). Moreover, excess weight and obesity are linked to numerous metabolic and cardiovascular issues, including diabetes, heart disease, hypertension, etc.
Sleep and diabetes
Another aspect of cardiovascular health that is less directly linked to sleep is glucose metabolism. When there is excess blood glucose, or the cells are unable to metabolise it effectively, as is the case for diabetics, the risk of heart disease or stroke is significantly elevated. Many factors affect this, but poor sleep is one of them. Various studies have found that sleep deprivation leads to poorer glucose metabolism and may also worsen atherosclerosis in people with diabetes. Even for those who do not have diabetes, sleep deprivation has been associated with prediabetes or increased spikes or crashes in blood sugar.
Sleep and heart rate
Another way in which sleep influences cardiovascular health is in terms of heart rate. Poor sleep and interruptions can lead to a sudden heart rate fluctuation and insufficient time spent in deep NREM sleep. Research has suggested that people who have trouble sleeping, wake up frequently during the night or report regular nightmares are also more likely to complain of an irregular heartbeat. In addition, studies have also detected an association between poor sleep and chest pain.
This could be related to the fact that the heart feels like it is racing when woken up suddenly or to non-cardiac factors such as heartburn or acid reflux which can affect sleep quality. Other factors that can also come into play are anxiety or mood disorders, which have also been linked to a lack of sufficient sleep and can lead to a feeling of panic, the heart racing, or actual fluctuations in a heartbeat.
Sleeping disorders
A number of sleeping disorders are also tied to heart disease, stroke or similar conditions. The most frequent one is sleep apnea or obstructive sleep apnea (OSA). This is a breathing disorder during which people have lapses in breathing during sleep due to airway blockages or interrupted breathing. This, in turn, leads to fragmented sleep and is tied to various cardiovascular issues.
People with sleep apnea have been shown to have disturbed respiration, lower blood oxygen levels, and a higher risk for cardiovascular illness, strokes or heart attacks. If you sleep badly, feel tired during the day or snore loudly, it may be worth getting a sleep study to check for sleep apnea.
Other sleeping disorders such as restless leg syndrome or periodic limb movement disorder can also affect sleep and may induce elevated heart rate or blood pressure during sleep, although they are much rarer than OSA. Other recent studies have also found that a misalignment of the circadian rhythm, which occurs when the body clock does not follow the pattern of day and night, can also increase the risk of cardiovascular problems.
For instance, people who worked night shifts or late hours and slept during the day were seen to have a higher likelihood of hypertension, obesity, diabetes and cardiac events such as heart attacks or strokes. There are other ways in which lack of sleep can influence health and the heart as well, but the above provides a comprehensive list of the possible reasons why getting sufficient sleep is important for overall well-being.
It is clear that sleep deprivation can harm the heart, and it is important for everyone, particularly those with a risk of cardiovascular or associated illnesses, to ensure they get regular, good sleep daily.
Improving heart health with sleep
Fortunately, there are steps that can be taken for people who have trouble sleeping, which can enable them to improve sleep duration and quality. Some studies suggest that improved sleep and regular sleep patterns can even reduce the likelihood of certain cardiovascular problems, though this has yet to be tested more widely.
In many cases, the connection between poor sleep and cardiovascular risks can be a vicious cycle. Problems like diabetes, anxiety or elevated heart rate make it difficult to fall asleep or have an uninterrupted sleep, which causes more of these symptoms and the associated risks of not sleeping enough. But there are certain things that can be done to try and improve sleep quality in such cases, as well as in general. Some of these are:
Consistent, regular sleep timings: Most experts say the easiest and most reliable way to ensure good sleep and regular timings is to create a routine and set times for sleeping and waking up, which do not fluctuate too much, even on weekends. This allows your body to get used to the habit and creates a regularity for sleep which is in tune with your circadian rhythm. Avoiding late-night activity as much as possible and sticking to the same timings over many weeks, months or years is likely to improve sleep quality significantly. Avoiding unregulated napping may also help with this.
Avoiding screens and blue light before bed: Most experts suggest that you should avoid blue light from screens such as laptops, mobiles and TVs for 30 minutes to an hour before bed. These artificial lights stimulate the brain and make it harder to fall asleep, particularly close to bedtime. Instead, having a regular pre-sleep routine and reading a book or deep breathing might help with falling asleep more easily. Getting enough natural light during the day can also play a role in helping you fall asleep.
Diet and exercise: Other lifestyle factors such as diet, exercise and so on can also play a role in alleviating some of these symptoms that disturb sleep. Sufficient physical activity during the day, but not too close to bedtime, can help tire out the body and improve sleep quality. Similarly, avoiding eating at least a couple of hours before bedtime and avoiding meals that are too heavy or high in fats and sugars can also be useful in terms of enabling better sleep.
Making the bedroom an oasis: Although this may be more difficult in the ‘work from home’ era, experts recommend that the bedroom be devoted to rest and relaxation and separated from parts of the home or other places which are associated with productivity and activity. Keeping the bedroom cool, dark, quiet and free from distractions, screens or devices can create a strong separation between sleep time and wakefulness.
Avoiding stimulants: Stimulants such as caffeine or alcohol should be avoided for at least a few hours before bedtime, and for those with consistent sleeping problems, eliminated as much as possible. Not eating or drinking for a few hours before bed and avoiding items that are high in sugar or caffeine can help with sleep quality. Alcohol may seem like it helps you fall asleep, but it also leads to more sleep interruptions and a lower quality of sleep.
By following these steps, you’re not just enabling a better quality of sleep but also actively taking steps towards improved heart health. It may be worth consulting a sleep specialist if you still have regular, restful sleep issues.
Conclusion
Sleeping seven to nine hours a night is essential for rest, recovery, and cardiovascular health. A lack of sufficient sleep has been linked to various conditions, from high blood pressure and obesity to diabetes and cardiac events. Simply put, sleep is as important as diet and exercise in maintaining good heart health. By being aware of its importance and taking steps to improve the quality of sleep, you can ensure you stay heart-healthy and recuperate properly.
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
- https://health.clevelandclinic.org/for-a-healthy-heart-get-enough-sleep/
- https://www.health.harvard.edu/blog/how-does-sleep-affect-your-heart-rate-2021012921846
- https://www.cdc.gov/bloodpressure/sleep.htm
- https://www.cdc.gov/sleep/index.html
- https://www.webmd.com/sleep-disorders/features/how-sleep-affects-your-heart
