How blood sugar affects athletic performance<\/h2>\n\n\n\n![\"Chow](\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/11\/chow-mein-1024x575.jpg\")
<\/figure>\n\n\n\nThe type of sugars in your diet \u2014 and how your body processes them \u2014 influences how glucose enters the bloodstream and fuels your workout. Both elevated and depleted blood glucose can impair performance.<\/p>\n\n\n\n
Chronic high blood sugar may even blunt your body\u2019s adaptive response to exercise. Research published in Nature Metabolism<\/a><\/em> shows that persistently elevated glucose can reduce oxygen uptake during aerobic activity and hinder muscle growth.<\/p>\n\n\n\nAerobic training increases your muscles\u2019 ability to absorb oxygen and store glycogen. But if blood glucose remains too high, this adaptive response is weakened, limiting long-term performance gains. Worse, low aerobic fitness is closely linked to increased risk of premature death.<\/p>\n\n\n\n
Fuel use during exercise<\/h2>\n\n\n\n
Glucose and free fatty acids are your primary fuels during exercise. Here\u2019s how energy demand is typically met during a workout:<\/p>\n\n\n\n
\n- First 15 minutes<\/strong>: Glucose is drawn from your bloodstream.<\/li>\n\n\n\n
- After 15\u201330 minutes<\/strong>: Your liver breaks down glycogen to release glucose.<\/li>\n\n\n\n
- Beyond 30 minutes<\/strong>: Fatty acids become the dominant fuel source.<\/li>\n<\/ul>\n\n\n\n
Exercise depletes glucose and glycogen stores, which can take 4\u20136 hours to fully replenish depending on intensity and duration.<\/p>\n\n\n\n
A balanced intake of carbohydrates, fats, and protein is crucial. Dietary fat provides essential fatty acids and fat-soluble vitamins, and supports oxygen transport into skeletal muscle during exercise. This is where metabolic flexibility becomes important.<\/p>\n\n\n\n
What is metabolic flexibility?<\/h2>\n\n\n\n
Metabolic flexibility refers to your body\u2019s ability to switch between burning glucose and fat for energy. It\u2019s what allows you to perform well, whether you\u2019ve just eaten or are training fasted. This flexibility is influenced by diet composition, physical conditioning, and the intensity and duration of workouts.<\/p>\n\n\n\n
Glucose oxidation<\/strong> happens after meals: insulin helps cells absorb glucose for energy.
Fat oxidation<\/strong> kicks in between meals or during extended exercise, as your body taps into fat stores.<\/p>\n\n\n\nA loss of this flexibility \u2014 for instance, from constant carb-heavy meals and sedentary behavior \u2014 can lead to poor glucose regulation and reduced athletic performance.<\/p>\n\n\n\n
The role of glucose as fuel<\/h2>\n\n\n\n![\"\"](\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/10\/athletic-performance-chart.png\")
<\/figure>\n\n\n\nGlucose plays a central role in determining both your effort and output. Athletes have different macronutrient needs depending on their sport, training cycle, and goals. Carbohydrates are often the go-to fuel due to their rapid availability, while fat provides a more sustained energy source but requires more time to metabolize.<\/p>\n\n\n\n
The key is not choosing between the two \u2014 it\u2019s using both effectively. Fat may offer more calories per gram, but carbs are more accessible when intensity ramps up. Well-planned nutrition improves both performance and recovery.<\/p>\n\n\n\n
The role of fat as fuel<\/h2>\n\n\n\n
Fat becomes the primary fuel at lower intensities. Endurance athletes, in particular, benefit from tapping into fat reserves during long events. This doesn\u2019t mean carbohydrates should be abandoned \u2014 complex carbs remain crucial for sustained energy in the hours leading up to a session.<\/p>\n\n\n\n
There\u2019s evidence that elite endurance athletes, including Ironman competitors, derive performance benefits from fat oxidation. Enhancing this pathway through training and diet (without entirely eliminating carbs) supports better fuel efficiency and metabolic resilience.<\/p>\n\n\n\n
Ideal glucose levels for athletic performance<\/h2>\n\n\n\n![\"HRV](\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/10\/sporlab-XiZ7pRvCzro-unsplash-1024x576.jpg\")
<\/figure>\n\n\n\nFor those engaging in high-intensity workouts or endurance events, maintaining glucose within a healthy range is essential. If blood sugar dips too low, performance and cognitive function decline rapidly.<\/p>\n\n\n\n
While individual targets vary, the general guidance is:<\/p>\n\n\n\n
\n- Pre- and post-exercise:<\/strong> 70\u2013110\u202fmg\/dL is considered optimal.<\/li>\n\n\n\n
- During intense activity:<\/strong> Some fluctuation is normal, and temporary rises above 110\u202fmg\/dL may reflect carbohydrate intake.<\/li>\n<\/ul>\n\n\n\n
While a CGM (continuous glucose monitor) won\u2019t tell you in real time if you’re “ready to race,” it can help you learn from your training and adapt your strategy.<\/p>\n\n\n\n
Using a CGM can offer useful guidance about your fuelling, but it’s not a real-time tool. Starting with a good blood glucose level is advisable, but that doesn’t provide insight into underlying glycogen stores, which are built up in the days leading up to long training sessions or endurance events. But looking at CGM data can tell you about your fuelling, and can be used to refine your strategy going forward.<\/p>\n\n\n\n
\n- Test your pre-race meal<\/strong>: Eat 3\u20134 hours before a training session and track your glucose. You want a rise followed by a return to baseline before you start.<\/li>\n\n\n\n
- Experiment with top-ups<\/strong>: Try a banana, sports drink, or gel 30\u201360 minutes pre-run. Stable, moderate increases (~100\u2013120\u202fmg\/dL) are ideal.<\/li>\n\n\n\n
- During training<\/strong>, look for smooth glucose curves and few crashes.<\/li>\n\n\n\n
- A spike post-exercise<\/strong> (140\u2013180 mg\/dL) is normal, especially if you eat or drink carbs.<\/li>\n\n\n\n
- Getting back to baseline (80\u2013100 mg\/dL) within 2\u20133 hours<\/strong> is a good recovery sign.<\/li>\n\n\n\n
- Sustained highs or overnight spikes may indicate stress, under-recovery, or poor fueling<\/strong>.<\/li>\n<\/ul>\n\n\n\n
Conclusion<\/h2>\n\n\n\n
Glucose is a central player in both performance and health. Metabolic flexibility \u2014 the ability to switch between glucose and fat \u2014 is what allows athletes to train hard, recover well, and adapt over time.<\/p>\n\n\n\n
A diet balanced in protein, complex carbs, and healthy fats supports glucose stability, while regular, well-timed activity can fine-tune your body\u2019s fuel usage. For those using CGMs, the goal isn\u2019t to react to every reading \u2014 it\u2019s to gather insights that sharpen your fueling over time.<\/p>\n\n\n\n
References<\/strong><\/p>\n\n\n\n\n- Hyperglycaemia is associated with impaired muscle signalling and aerobic adaptation to exercise<\/a><\/em><\/li>\n\n\n\n
- Balance of substrate oxidation during submaximal exercise in lean and obese people<\/a><\/em><\/li>\n\n\n\n
- Gluconeogenesis during endurance exercise in cyclists habituated to a long\u2010term low carbohydrate high\u2010fat diet<\/a><\/em><\/li>\n\n\n\n
- Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners<\/a><\/em><\/li>\n<\/ol>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.<\/p>\n","protected":false},"author":9,"featured_media":1088,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[6,4],"tags":[],"class_list":["post-1076","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-exercise","category-metabolic-health"],"acf":[],"yoast_head":"\n
Glucose and athletic performance: How blood sugar fuels your training - Ultrahuman<\/title>\n<meta name=\"description\" content=\"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Glucose and athletic performance: How blood sugar fuels your training\" \/>\n<meta property=\"og:description\" content=\"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\" \/>\n<meta property=\"og:site_name\" content=\"Ultrahuman\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/ultrahumanhq\" \/>\n<meta property=\"article:published_time\" content=\"2025-07-10T06:21:05+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-07-10T06:22:21+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2500\" \/>\n\t<meta property=\"og:image:height\" content=\"1670\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Team Ultrahuman\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@UltrahumanHQ\" \/>\n<meta name=\"twitter:site\" content=\"@UltrahumanHQ\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Team Ultrahuman\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"6 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\"},\"author\":{\"name\":\"Team Ultrahuman\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/47e73966094408ddf4ebb9febb348e27\"},\"headline\":\"Glucose and athletic performance: How blood sugar fuels your training\",\"datePublished\":\"2025-07-10T06:21:05+00:00\",\"dateModified\":\"2025-07-10T06:22:21+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\"},\"wordCount\":1022,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#organization\"},\"image\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg\",\"articleSection\":[\"Exercise\",\"Metabolic Health\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\",\"url\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\",\"name\":\"Glucose and athletic performance: How blood sugar fuels your training - Ultrahuman\",\"isPartOf\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg\",\"datePublished\":\"2025-07-10T06:21:05+00:00\",\"dateModified\":\"2025-07-10T06:22:21+00:00\",\"description\":\"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.\",\"breadcrumb\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage\",\"url\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg\",\"contentUrl\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg\",\"width\":2500,\"height\":1670},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/blog.ultrahuman.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Glucose and athletic performance: How blood sugar fuels your training\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#website\",\"url\":\"https:\/\/blog.ultrahuman.com\/blog\/\",\"name\":\"Ultrahuman\",\"description\":\"Blog\",\"publisher\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/blog.ultrahuman.com\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#organization\",\"name\":\"Ultrahuman\",\"url\":\"https:\/\/blog.ultrahuman.com\/blog\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2025\/05\/4Ww9Uqhk_400x400.jpg\",\"contentUrl\":\"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2025\/05\/4Ww9Uqhk_400x400.jpg\",\"width\":400,\"height\":400,\"caption\":\"Ultrahuman\"},\"image\":{\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/www.facebook.com\/ultrahumanhq\",\"https:\/\/x.com\/UltrahumanHQ\"]},{\"@type\":\"Person\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/47e73966094408ddf4ebb9febb348e27\",\"name\":\"Team Ultrahuman\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/fb2a8e9f2fd4cc81b528bb78804d88f48aae6513ff4cbc7e4b6df4d72f2b5ac3?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/fb2a8e9f2fd4cc81b528bb78804d88f48aae6513ff4cbc7e4b6df4d72f2b5ac3?s=96&d=mm&r=g\",\"caption\":\"Team Ultrahuman\"},\"description\":\"Ultrahuman is the world's most comprehensive self-quantification platform. Ultrahuman's products include the Ultrahuman Ring AIR, the world's lightest sleep-tracking wearable; Ultrahuman M1, a continuous glucose monitoring platform; Blood Vision, a preventive blood testing platform with pioneering UltraTrace\u2122 technology; and Ultrahuman Home, a revolutionary health device for your home. By collating a large set of biomarkers on an integrated platform, Ultrahuman creates a grand unified view of the human body.\",\"sameAs\":[\"https:\/\/www.ultrahuman.com\"],\"url\":\"https:\/\/blog.ultrahuman.com\/blog\/author\/teamultrahuman\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Glucose and athletic performance: How blood sugar fuels your training - Ultrahuman","description":"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/","og_locale":"en_US","og_type":"article","og_title":"Glucose and athletic performance: How blood sugar fuels your training","og_description":"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.","og_url":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/","og_site_name":"Ultrahuman","article_publisher":"https:\/\/www.facebook.com\/ultrahumanhq","article_published_time":"2025-07-10T06:21:05+00:00","article_modified_time":"2025-07-10T06:22:21+00:00","og_image":[{"width":2500,"height":1670,"url":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg","type":"image\/jpeg"}],"author":"Team Ultrahuman","twitter_card":"summary_large_image","twitter_creator":"@UltrahumanHQ","twitter_site":"@UltrahumanHQ","twitter_misc":{"Written by":"Team Ultrahuman","Est. reading time":"6 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#article","isPartOf":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/"},"author":{"name":"Team Ultrahuman","@id":"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/47e73966094408ddf4ebb9febb348e27"},"headline":"Glucose and athletic performance: How blood sugar fuels your training","datePublished":"2025-07-10T06:21:05+00:00","dateModified":"2025-07-10T06:22:21+00:00","mainEntityOfPage":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/"},"wordCount":1022,"commentCount":0,"publisher":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/#organization"},"image":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage"},"thumbnailUrl":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg","articleSection":["Exercise","Metabolic Health"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/","url":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/","name":"Glucose and athletic performance: How blood sugar fuels your training - Ultrahuman","isPartOf":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage"},"image":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage"},"thumbnailUrl":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg","datePublished":"2025-07-10T06:21:05+00:00","dateModified":"2025-07-10T06:22:21+00:00","description":"Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.","breadcrumb":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#primaryimage","url":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg","contentUrl":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2022\/09\/glucoseo-range-athletes.jpg","width":2500,"height":1670},{"@type":"BreadcrumbList","@id":"https:\/\/blog.ultrahuman.com\/blog\/ideal-glucose-range-for-athletic-performance-good-health\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/blog.ultrahuman.com\/blog\/"},{"@type":"ListItem","position":2,"name":"Glucose and athletic performance: How blood sugar fuels your training"}]},{"@type":"WebSite","@id":"https:\/\/blog.ultrahuman.com\/blog\/#website","url":"https:\/\/blog.ultrahuman.com\/blog\/","name":"Ultrahuman","description":"Blog","publisher":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/blog.ultrahuman.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/blog.ultrahuman.com\/blog\/#organization","name":"Ultrahuman","url":"https:\/\/blog.ultrahuman.com\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2025\/05\/4Ww9Uqhk_400x400.jpg","contentUrl":"https:\/\/blog.ultrahuman.com\/wp-content\/uploads\/2025\/05\/4Ww9Uqhk_400x400.jpg","width":400,"height":400,"caption":"Ultrahuman"},"image":{"@id":"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/ultrahumanhq","https:\/\/x.com\/UltrahumanHQ"]},{"@type":"Person","@id":"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/47e73966094408ddf4ebb9febb348e27","name":"Team Ultrahuman","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/blog.ultrahuman.com\/blog\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/fb2a8e9f2fd4cc81b528bb78804d88f48aae6513ff4cbc7e4b6df4d72f2b5ac3?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/fb2a8e9f2fd4cc81b528bb78804d88f48aae6513ff4cbc7e4b6df4d72f2b5ac3?s=96&d=mm&r=g","caption":"Team Ultrahuman"},"description":"Ultrahuman is the world's most comprehensive self-quantification platform. Ultrahuman's products include the Ultrahuman Ring AIR, the world's lightest sleep-tracking wearable; Ultrahuman M1, a continuous glucose monitoring platform; Blood Vision, a preventive blood testing platform with pioneering UltraTrace\u2122 technology; and Ultrahuman Home, a revolutionary health device for your home. By collating a large set of biomarkers on an integrated platform, Ultrahuman creates a grand unified view of the human body.","sameAs":["https:\/\/www.ultrahuman.com"],"url":"https:\/\/blog.ultrahuman.com\/blog\/author\/teamultrahuman\/"}]}},"_links":{"self":[{"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/posts\/1076","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/comments?post=1076"}],"version-history":[{"count":0,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/posts\/1076\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/media\/1088"}],"wp:attachment":[{"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/media?parent=1076"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/categories?post=1076"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.ultrahuman.com\/blog\/wp-json\/wp\/v2\/tags?post=1076"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/figure>\n\n\n\nThe type of sugars in your diet \u2014 and how your body processes them \u2014 influences how glucose enters the bloodstream and fuels your workout. Both elevated and depleted blood glucose can impair performance.<\/p>\n\n\n\n
Chronic high blood sugar may even blunt your body\u2019s adaptive response to exercise. Research published in Nature Metabolism<\/a><\/em> shows that persistently elevated glucose can reduce oxygen uptake during aerobic activity and hinder muscle growth.<\/p>\n\n\n\n Aerobic training increases your muscles\u2019 ability to absorb oxygen and store glycogen. But if blood glucose remains too high, this adaptive response is weakened, limiting long-term performance gains. Worse, low aerobic fitness is closely linked to increased risk of premature death.<\/p>\n\n\n\n Glucose and free fatty acids are your primary fuels during exercise. Here\u2019s how energy demand is typically met during a workout:<\/p>\n\n\n\n Exercise depletes glucose and glycogen stores, which can take 4\u20136 hours to fully replenish depending on intensity and duration.<\/p>\n\n\n\n A balanced intake of carbohydrates, fats, and protein is crucial. Dietary fat provides essential fatty acids and fat-soluble vitamins, and supports oxygen transport into skeletal muscle during exercise. This is where metabolic flexibility becomes important.<\/p>\n\n\n\n Metabolic flexibility refers to your body\u2019s ability to switch between burning glucose and fat for energy. It\u2019s what allows you to perform well, whether you\u2019ve just eaten or are training fasted. This flexibility is influenced by diet composition, physical conditioning, and the intensity and duration of workouts.<\/p>\n\n\n\n Glucose oxidation<\/strong> happens after meals: insulin helps cells absorb glucose for energy. A loss of this flexibility \u2014 for instance, from constant carb-heavy meals and sedentary behavior \u2014 can lead to poor glucose regulation and reduced athletic performance.<\/p>\n\n\n\n Glucose plays a central role in determining both your effort and output. Athletes have different macronutrient needs depending on their sport, training cycle, and goals. Carbohydrates are often the go-to fuel due to their rapid availability, while fat provides a more sustained energy source but requires more time to metabolize.<\/p>\n\n\n\n The key is not choosing between the two \u2014 it\u2019s using both effectively. Fat may offer more calories per gram, but carbs are more accessible when intensity ramps up. Well-planned nutrition improves both performance and recovery.<\/p>\n\n\n\n Fat becomes the primary fuel at lower intensities. Endurance athletes, in particular, benefit from tapping into fat reserves during long events. This doesn\u2019t mean carbohydrates should be abandoned \u2014 complex carbs remain crucial for sustained energy in the hours leading up to a session.<\/p>\n\n\n\n There\u2019s evidence that elite endurance athletes, including Ironman competitors, derive performance benefits from fat oxidation. Enhancing this pathway through training and diet (without entirely eliminating carbs) supports better fuel efficiency and metabolic resilience.<\/p>\n\n\n\n For those engaging in high-intensity workouts or endurance events, maintaining glucose within a healthy range is essential. If blood sugar dips too low, performance and cognitive function decline rapidly.<\/p>\n\n\n\n While individual targets vary, the general guidance is:<\/p>\n\n\n\n While a CGM (continuous glucose monitor) won\u2019t tell you in real time if you’re “ready to race,” it can help you learn from your training and adapt your strategy.<\/p>\n\n\n\n Using a CGM can offer useful guidance about your fuelling, but it’s not a real-time tool. Starting with a good blood glucose level is advisable, but that doesn’t provide insight into underlying glycogen stores, which are built up in the days leading up to long training sessions or endurance events. But looking at CGM data can tell you about your fuelling, and can be used to refine your strategy going forward.<\/p>\n\n\n\n Glucose is a central player in both performance and health. Metabolic flexibility \u2014 the ability to switch between glucose and fat \u2014 is what allows athletes to train hard, recover well, and adapt over time.<\/p>\n\n\n\n A diet balanced in protein, complex carbs, and healthy fats supports glucose stability, while regular, well-timed activity can fine-tune your body\u2019s fuel usage. For those using CGMs, the goal isn\u2019t to react to every reading \u2014 it\u2019s to gather insights that sharpen your fueling over time.<\/p>\n\n\n\n References<\/strong><\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Discover how glucose affects athletic performance and learn how to use CGM data to fine-tune your fueling before and after training or racing.<\/p>\n","protected":false},"author":9,"featured_media":1088,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[6,4],"tags":[],"class_list":["post-1076","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-exercise","category-metabolic-health"],"acf":[],"yoast_head":"\nFuel use during exercise<\/h2>\n\n\n\n
\n
What is metabolic flexibility?<\/h2>\n\n\n\n
Fat oxidation<\/strong> kicks in between meals or during extended exercise, as your body taps into fat stores.<\/p>\n\n\n\nThe role of glucose as fuel<\/h2>\n\n\n\n
<\/figure>\n\n\n\nThe role of fat as fuel<\/h2>\n\n\n\n
Ideal glucose levels for athletic performance<\/h2>\n\n\n\n
<\/figure>\n\n\n\n\n
\n
Conclusion<\/h2>\n\n\n\n
\n