Type

Wearables

Sleep

Part of

Sleep

Blood biomarker

Part of

Sleep

Sleep Duration

Sleep duration refers to the total time you spend asleep within 24 hours, representing a foundational pillar of health and recovery.

Sleep Duration

Normal range

7-9 hours per night

Normal range

7-9 hours per night

Normal range

Sleep Duration

Sleep duration refers to the total time you spend asleep within 24 hours, representing a foundational pillar of health and recovery.

Sleep Duration

Normal range

7-9 hours per night

Normal range

7-9 hours per night

Normal range

Sleep Duration

Sleep duration refers to the total time you spend asleep within 24 hours, representing a foundational pillar of health and recovery.

Sleep Duration

Normal range

7-9 hours per night

Normal range

7-9 hours per night

Normal range

Sleep Duration

Sleep duration refers to the total time you spend asleep within 24 hours, representing a foundational pillar of health and recovery.

Sleep Duration

Normal range

7-9 hours per night

Normal range

7-9 hours per night

Normal range

Sleep Duration

Dr. Thiviya Sivakanthan

MBBS

The Silent Powerhouse Behind Every Health Metric

Sleep isn’t just rest—it’s one of the most powerful tools you have for healing, regulating, and rebuilding your body and mind. Yet, in a world that glorifies hustle and stimulation, sleep is often the first thing we sacrifice. Sleep duration is a vital sign. Consistently getting the right amount of sleep lowers your risk of nearly every chronic disease, improves cognitive function, sharpens emotional regulation, and supports metabolic health.

Track it like you would your workouts or macros—because the hours you sleep shape everything from your mood to your muscle mass.

Get tested

Why Sleep is Non-Negotiable

Sleep is where the magic happens—repair, memory, immunity, and hormone balance all depend on it.

What Happens When You Sleep

This isn’t downtime—it’s an active physiological state that primes you to perform, recover, and thrive.

How to Improve Sleep Quantity (and Quality)

Simple, evidence-backed changes can radically upgrade your sleep and, with it, every system in your body.

Understanding Your Results

Learn how your wearable interprets sleep time, what the data really tells you, and how to set realistic targets.

Why Sleep is Non-Negotiable

When you sleep, your body enters repair mode—clearing waste from the brain, balancing blood sugar, regulating hormones, repairing muscle tissue, and strengthening the immune system. It’s essential not just for feeling rested, but for overall survival and performance.

It’s not just about how much sleep you get—it’s about consistency. Chronic sleep deprivation (less than 6 hours per night) is linked to:

Higher all-cause mortality
Impaired glucose tolerance
Increased risk of obesity, heart disease, stroke, and dementia
Poor emotional regulation and mental health
Decreased physical performance and recovery

But perhaps the most powerful argument for sleep is this:

From an evolutionary standpoint, sleep should be a liability.
In the wild, lying unconscious for 7–9 hours a night, unable to hunt or defend against predators, would seem like a poor survival strategy. And yet, across species and through millions of years of evolution, sleep has persisted.

That tells us something profound:

Sleep is so essential to human health and survival that nature hasn’t found a way around it. It’s hardwired into our biology because it supports every system that keeps us alive and thriving.

In short, sleep is your foundation. Without it, even the best diet and training plans unravel. If you’re looking for one habit with the power to improve your brain, body, and mood all at once—start with sleep.

Why Sleep is Non-Negotiable

It’s not just about how much sleep you get—it’s about consistency. Chronic sleep deprivation (less than 6 hours per night) is linked to:

Higher all-cause mortality
Impaired glucose tolerance
Increased risk of obesity, heart disease, stroke, and dementia
Poor emotional regulation and mental health
Decreased physical performance and recovery

But perhaps the most powerful argument for sleep is this:

That tells us something profound:

Sleep is so essential to human health and survival that nature hasn’t found a way around it. It’s hardwired into our biology because it supports every system that keeps us alive and thriving.

Why Sleep is Non-Negotiable

It’s not just about how much sleep you get—it’s about consistency. Chronic sleep deprivation (less than 6 hours per night) is linked to:

Higher all-cause mortality
Impaired glucose tolerance
Increased risk of obesity, heart disease, stroke, and dementia
Poor emotional regulation and mental health
Decreased physical performance and recovery

But perhaps the most powerful argument for sleep is this:

That tells us something profound:

Sleep is so essential to human health and survival that nature hasn’t found a way around it. It’s hardwired into our biology because it supports every system that keeps us alive and thriving.

Why Sleep is Non-Negotiable

It’s not just about how much sleep you get—it’s about consistency. Chronic sleep deprivation (less than 6 hours per night) is linked to:

Higher all-cause mortality
Impaired glucose tolerance
Increased risk of obesity, heart disease, stroke, and dementia
Poor emotional regulation and mental health
Decreased physical performance and recovery

But perhaps the most powerful argument for sleep is this:

That tells us something profound:

Sleep is so essential to human health and survival that nature hasn’t found a way around it. It’s hardwired into our biology because it supports every system that keeps us alive and thriving.

What Happens When You Sleep

Sleep isn’t a passive state. It’s a carefully choreographed sequence of stages, each delivering distinct and vital physiological benefits:

Stage 1 & 2 (Light Sleep): These initial stages serve as a bridge between wakefulness and deeper sleep. During light sleep, your heart rate slows, body temperature drops, and muscles begin to relax. This phase also helps regulate mood and initiates the body’s repair mechanisms. It’s essential for preparing the brain and body to enter the more restorative stages ahead.
Stage 3 (Deep Sleep): Often called slow-wave or restorative sleep, deep sleep is where the most significant physical restoration happens. Growth hormone is released to promote tissue repair and muscle growth, the immune system strengthens, and bone metabolism is supported. Deep sleep also plays a role in clearing metabolic waste from the brain, which is critical for cognitive function and long-term brain health.
REM Sleep (Rapid Eye Movement): This stage is marked by increased brain activity resembling wakefulness, but the body remains relaxed. REM sleep is vital for learning, memory consolidation, emotional processing, and creativity. During REM, the brain processes and integrates new information, supports emotional resilience, and facilitates problem-solving abilities.

Throughout a typical night, the body cycles through these stages about 4 to 6 times in a repeating pattern. Each cycle lasts approximately 90 minutes, with deep sleep dominating earlier cycles and REM sleep lengthening toward morning.

Disrupting this natural rhythm by cutting sleep short or experiencing fragmented sleep prevents your body from completing full cycles. Unlike some other bodily processes, you cannot simply “catch up” on lost sleep by sleeping longer the next night. Missing deep or REM sleep has immediate and cumulative effects on physical recovery, cognitive function, mood regulation, and immune health.

In short, maintaining the full sequence and duration of sleep cycles is essential for overall health, performance, and longevity.

What Happens When You Sleep

Sleep isn’t a passive state. It’s a carefully choreographed sequence of stages, each delivering distinct and vital physiological benefits:

Stage 1 & 2 (Light Sleep): These initial stages serve as a bridge between wakefulness and deeper sleep. During light sleep, your heart rate slows, body temperature drops, and muscles begin to relax. This phase also helps regulate mood and initiates the body’s repair mechanisms. It’s essential for preparing the brain and body to enter the more restorative stages ahead.
Stage 3 (Deep Sleep): Often called slow-wave or restorative sleep, deep sleep is where the most significant physical restoration happens. Growth hormone is released to promote tissue repair and muscle growth, the immune system strengthens, and bone metabolism is supported. Deep sleep also plays a role in clearing metabolic waste from the brain, which is critical for cognitive function and long-term brain health.
REM Sleep (Rapid Eye Movement): This stage is marked by increased brain activity resembling wakefulness, but the body remains relaxed. REM sleep is vital for learning, memory consolidation, emotional processing, and creativity. During REM, the brain processes and integrates new information, supports emotional resilience, and facilitates problem-solving abilities.

In short, maintaining the full sequence and duration of sleep cycles is essential for overall health, performance, and longevity.

What Happens When You Sleep

Sleep isn’t a passive state. It’s a carefully choreographed sequence of stages, each delivering distinct and vital physiological benefits:

Stage 1 & 2 (Light Sleep): These initial stages serve as a bridge between wakefulness and deeper sleep. During light sleep, your heart rate slows, body temperature drops, and muscles begin to relax. This phase also helps regulate mood and initiates the body’s repair mechanisms. It’s essential for preparing the brain and body to enter the more restorative stages ahead.
Stage 3 (Deep Sleep): Often called slow-wave or restorative sleep, deep sleep is where the most significant physical restoration happens. Growth hormone is released to promote tissue repair and muscle growth, the immune system strengthens, and bone metabolism is supported. Deep sleep also plays a role in clearing metabolic waste from the brain, which is critical for cognitive function and long-term brain health.
REM Sleep (Rapid Eye Movement): This stage is marked by increased brain activity resembling wakefulness, but the body remains relaxed. REM sleep is vital for learning, memory consolidation, emotional processing, and creativity. During REM, the brain processes and integrates new information, supports emotional resilience, and facilitates problem-solving abilities.

In short, maintaining the full sequence and duration of sleep cycles is essential for overall health, performance, and longevity.

What Happens When You Sleep

Sleep isn’t a passive state. It’s a carefully choreographed sequence of stages, each delivering distinct and vital physiological benefits:

Stage 1 & 2 (Light Sleep): These initial stages serve as a bridge between wakefulness and deeper sleep. During light sleep, your heart rate slows, body temperature drops, and muscles begin to relax. This phase also helps regulate mood and initiates the body’s repair mechanisms. It’s essential for preparing the brain and body to enter the more restorative stages ahead.
Stage 3 (Deep Sleep): Often called slow-wave or restorative sleep, deep sleep is where the most significant physical restoration happens. Growth hormone is released to promote tissue repair and muscle growth, the immune system strengthens, and bone metabolism is supported. Deep sleep also plays a role in clearing metabolic waste from the brain, which is critical for cognitive function and long-term brain health.
REM Sleep (Rapid Eye Movement): This stage is marked by increased brain activity resembling wakefulness, but the body remains relaxed. REM sleep is vital for learning, memory consolidation, emotional processing, and creativity. During REM, the brain processes and integrates new information, supports emotional resilience, and facilitates problem-solving abilities.

In short, maintaining the full sequence and duration of sleep cycles is essential for overall health, performance, and longevity.

How to Improve Sleep Quantity (and Quality)

Getting enough sleep isn’t just about clocking hours—it’s about cultivating habits that promote consistent, restorative sleep night after night. You don’t need perfect sleep every single night, but you do need reliable, good-enough sleep most of the time to function and recover well. Here’s how to naturally increase both how long and how well you sleep:

Set a Consistent Wind-Down Time
Create a nightly routine that signals your body it’s time to relax. Ideally, start winding down 60–90 minutes before bed by doing calming activities—reading, gentle stretching, or meditation. Doing this consistently (even on weekends) helps train your brain to anticipate sleep, making it easier to fall asleep and stay asleep.
Dim Screens and Avoid Blue Light Before Bed
Electronic devices emit blue light, which tricks your brain into thinking it’s daytime by suppressing melatonin—the hormone that helps you feel sleepy. Aim to reduce screen time at least 1–2 hours before bedtime or use blue light filters/glasses if you must use devices. This supports your body’s natural melatonin production and circadian rhythm.
Lower Caffeine Intake, Especially in the Afternoon
Caffeine blocks adenosine, a chemical that builds up in your brain to make you feel sleepy. Even if you feel fine, caffeine consumed after early afternoon can reduce your ability to fall asleep or achieve deep sleep stages. Consider limiting caffeine intake after 2 p.m., or switching to herbal teas or decaf in the afternoon and evening.
Optimise Your Sleep Environment
Your bedroom should be a sanctuary for sleep. Keep it cool (around 16–19°C or 60–67°F), dark (use blackout curtains or eye masks), and quiet (earplugs or white noise machines can help). A comfortable mattress and pillows tailored to your preference also support uninterrupted rest.
Limit Alcohol Consumption
While alcohol may help you fall asleep faster, it disrupts your sleep architecture by reducing the amount of deep sleep and REM sleep you get. This can lead to poorer quality sleep, more awakenings, and feeling less refreshed. If you drink, aim to do so earlier in the evening and in moderation.
Get Morning Light Exposure
Natural sunlight in the morning helps reset and anchor your internal clock, reinforcing your circadian rhythm. Aim to spend 15–30 minutes outside soon after waking, or sit by a bright window. This helps regulate sleep timing and can improve alertness during the day and sleep quality at night.
Treat Sleep Like TrainingThink of sleep not as a passive activity but as an essential “training session” for your body and brain. Just like you wouldn’t skip warming up or cooldown in exercise, don’t neglect your sleep preparation. Protect it fiercely by avoiding late-night stimulants or stressors, and prioritising recovery. Your daytime performance, mood, and health all depend on it.

How to Improve Sleep Quantity (and Quality)

Set a Consistent Wind-Down Time
Create a nightly routine that signals your body it’s time to relax. Ideally, start winding down 60–90 minutes before bed by doing calming activities—reading, gentle stretching, or meditation. Doing this consistently (even on weekends) helps train your brain to anticipate sleep, making it easier to fall asleep and stay asleep.
Dim Screens and Avoid Blue Light Before Bed
Electronic devices emit blue light, which tricks your brain into thinking it’s daytime by suppressing melatonin—the hormone that helps you feel sleepy. Aim to reduce screen time at least 1–2 hours before bedtime or use blue light filters/glasses if you must use devices. This supports your body’s natural melatonin production and circadian rhythm.
Lower Caffeine Intake, Especially in the Afternoon
Caffeine blocks adenosine, a chemical that builds up in your brain to make you feel sleepy. Even if you feel fine, caffeine consumed after early afternoon can reduce your ability to fall asleep or achieve deep sleep stages. Consider limiting caffeine intake after 2 p.m., or switching to herbal teas or decaf in the afternoon and evening.
Optimise Your Sleep Environment
Your bedroom should be a sanctuary for sleep. Keep it cool (around 16–19°C or 60–67°F), dark (use blackout curtains or eye masks), and quiet (earplugs or white noise machines can help). A comfortable mattress and pillows tailored to your preference also support uninterrupted rest.
Limit Alcohol Consumption
While alcohol may help you fall asleep faster, it disrupts your sleep architecture by reducing the amount of deep sleep and REM sleep you get. This can lead to poorer quality sleep, more awakenings, and feeling less refreshed. If you drink, aim to do so earlier in the evening and in moderation.
Get Morning Light Exposure
Natural sunlight in the morning helps reset and anchor your internal clock, reinforcing your circadian rhythm. Aim to spend 15–30 minutes outside soon after waking, or sit by a bright window. This helps regulate sleep timing and can improve alertness during the day and sleep quality at night.
Treat Sleep Like TrainingThink of sleep not as a passive activity but as an essential “training session” for your body and brain. Just like you wouldn’t skip warming up or cooldown in exercise, don’t neglect your sleep preparation. Protect it fiercely by avoiding late-night stimulants or stressors, and prioritising recovery. Your daytime performance, mood, and health all depend on it.

How to Improve Sleep Quantity (and Quality)

Set a Consistent Wind-Down Time
Create a nightly routine that signals your body it’s time to relax. Ideally, start winding down 60–90 minutes before bed by doing calming activities—reading, gentle stretching, or meditation. Doing this consistently (even on weekends) helps train your brain to anticipate sleep, making it easier to fall asleep and stay asleep.
Dim Screens and Avoid Blue Light Before Bed
Electronic devices emit blue light, which tricks your brain into thinking it’s daytime by suppressing melatonin—the hormone that helps you feel sleepy. Aim to reduce screen time at least 1–2 hours before bedtime or use blue light filters/glasses if you must use devices. This supports your body’s natural melatonin production and circadian rhythm.
Lower Caffeine Intake, Especially in the Afternoon
Caffeine blocks adenosine, a chemical that builds up in your brain to make you feel sleepy. Even if you feel fine, caffeine consumed after early afternoon can reduce your ability to fall asleep or achieve deep sleep stages. Consider limiting caffeine intake after 2 p.m., or switching to herbal teas or decaf in the afternoon and evening.
Optimise Your Sleep Environment
Your bedroom should be a sanctuary for sleep. Keep it cool (around 16–19°C or 60–67°F), dark (use blackout curtains or eye masks), and quiet (earplugs or white noise machines can help). A comfortable mattress and pillows tailored to your preference also support uninterrupted rest.
Limit Alcohol Consumption
While alcohol may help you fall asleep faster, it disrupts your sleep architecture by reducing the amount of deep sleep and REM sleep you get. This can lead to poorer quality sleep, more awakenings, and feeling less refreshed. If you drink, aim to do so earlier in the evening and in moderation.
Get Morning Light Exposure
Natural sunlight in the morning helps reset and anchor your internal clock, reinforcing your circadian rhythm. Aim to spend 15–30 minutes outside soon after waking, or sit by a bright window. This helps regulate sleep timing and can improve alertness during the day and sleep quality at night.
Treat Sleep Like TrainingThink of sleep not as a passive activity but as an essential “training session” for your body and brain. Just like you wouldn’t skip warming up or cooldown in exercise, don’t neglect your sleep preparation. Protect it fiercely by avoiding late-night stimulants or stressors, and prioritising recovery. Your daytime performance, mood, and health all depend on it.

How to Improve Sleep Quantity (and Quality)

Set a Consistent Wind-Down Time
Create a nightly routine that signals your body it’s time to relax. Ideally, start winding down 60–90 minutes before bed by doing calming activities—reading, gentle stretching, or meditation. Doing this consistently (even on weekends) helps train your brain to anticipate sleep, making it easier to fall asleep and stay asleep.
Dim Screens and Avoid Blue Light Before Bed
Electronic devices emit blue light, which tricks your brain into thinking it’s daytime by suppressing melatonin—the hormone that helps you feel sleepy. Aim to reduce screen time at least 1–2 hours before bedtime or use blue light filters/glasses if you must use devices. This supports your body’s natural melatonin production and circadian rhythm.
Lower Caffeine Intake, Especially in the Afternoon
Caffeine blocks adenosine, a chemical that builds up in your brain to make you feel sleepy. Even if you feel fine, caffeine consumed after early afternoon can reduce your ability to fall asleep or achieve deep sleep stages. Consider limiting caffeine intake after 2 p.m., or switching to herbal teas or decaf in the afternoon and evening.
Optimise Your Sleep Environment
Your bedroom should be a sanctuary for sleep. Keep it cool (around 16–19°C or 60–67°F), dark (use blackout curtains or eye masks), and quiet (earplugs or white noise machines can help). A comfortable mattress and pillows tailored to your preference also support uninterrupted rest.
Limit Alcohol Consumption
While alcohol may help you fall asleep faster, it disrupts your sleep architecture by reducing the amount of deep sleep and REM sleep you get. This can lead to poorer quality sleep, more awakenings, and feeling less refreshed. If you drink, aim to do so earlier in the evening and in moderation.
Get Morning Light Exposure
Natural sunlight in the morning helps reset and anchor your internal clock, reinforcing your circadian rhythm. Aim to spend 15–30 minutes outside soon after waking, or sit by a bright window. This helps regulate sleep timing and can improve alertness during the day and sleep quality at night.
Treat Sleep Like TrainingThink of sleep not as a passive activity but as an essential “training session” for your body and brain. Just like you wouldn’t skip warming up or cooldown in exercise, don’t neglect your sleep preparation. Protect it fiercely by avoiding late-night stimulants or stressors, and prioritising recovery. Your daytime performance, mood, and health all depend on it.

Get started

Understanding Your Results

Wearables track total sleep time based on a mix of movement, heart rate variability, and skin temperature. But remember, time in bed doesn’t equal time asleep—your tracker estimates when you’re truly asleep.

Sleep Duration Ranges (Adults):

Sleep category	Range	Interpretation
High Risk	<6 hours	Chronic sleep deprivation high likely to impact recovery and long-term health
Suboptimal	6-7 hours	Sleep deprivation likely to impact health and recovery
Optimal	7-9 hours	Optimal range for most adults allowing for peak recovery
High Recovery/ Demand	>9 hours	Sleep need indicating recovery demand or other issues (e.g. illness or depression)

Look at your trends over weeks, not nights. One bad night doesn’t ruin your health, just like one great night won’t fix chronic sleep debt.

Understanding Your Results

Sleep Duration Ranges (Adults):

Sleep category	Range	Interpretation
High Risk	<6 hours	Chronic sleep deprivation high likely to impact recovery and long-term health
Suboptimal	6-7 hours	Sleep deprivation likely to impact health and recovery
Optimal	7-9 hours	Optimal range for most adults allowing for peak recovery
High Recovery/ Demand	>9 hours	Sleep need indicating recovery demand or other issues (e.g. illness or depression)

Look at your trends over weeks, not nights. One bad night doesn’t ruin your health, just like one great night won’t fix chronic sleep debt.

Understanding Your Results

Sleep Duration Ranges (Adults):

Sleep category	Range	Interpretation
High Risk	<6 hours	Chronic sleep deprivation high likely to impact recovery and long-term health
Suboptimal	6-7 hours	Sleep deprivation likely to impact health and recovery
Optimal	7-9 hours	Optimal range for most adults allowing for peak recovery
High Recovery/ Demand	>9 hours	Sleep need indicating recovery demand or other issues (e.g. illness or depression)

Look at your trends over weeks, not nights. One bad night doesn’t ruin your health, just like one great night won’t fix chronic sleep debt.

Understanding Your Results

Sleep Duration Ranges (Adults):

Sleep category	Range	Interpretation
High Risk	<6 hours	Chronic sleep deprivation high likely to impact recovery and long-term health
Suboptimal	6-7 hours	Sleep deprivation likely to impact health and recovery
Optimal	7-9 hours	Optimal range for most adults allowing for peak recovery
High Recovery/ Demand	>9 hours	Sleep need indicating recovery demand or other issues (e.g. illness or depression)

Look at your trends over weeks, not nights. One bad night doesn’t ruin your health, just like one great night won’t fix chronic sleep debt.

The Takeaway

Sleep isn’t a luxury—it’s a biological necessity that fuels every system in your body. From muscle recovery and weight regulation to immune function and mental clarity, the hours you sleep set the tone for the hours you’re awake.

Track your sleep like a performance metric. Aim for consistency, build habits that support it, and treat it as the ultimate recovery tool—not an afterthought.

The Takeaway

Track your sleep like a performance metric. Aim for consistency, build habits that support it, and treat it as the ultimate recovery tool—not an afterthought.

The Takeaway

Track your sleep like a performance metric. Aim for consistency, build habits that support it, and treat it as the ultimate recovery tool—not an afterthought.

The Takeaway

Track your sleep like a performance metric. Aim for consistency, build habits that support it, and treat it as the ultimate recovery tool—not an afterthought.

References

Walker, M. (2017). Why We Sleep. Penguin Random House.
Hirshkowitz, M., et al. (2015). National Sleep Foundation’s sleep time duration recommendations. Sleep Health, 1(1), 40–43.
Van Cauter, E., et al. (2008). Sleep and metabolic function. PLoS Med, 5(3): e57.
Medic, G., et al. (2017). Short- and long-term health consequences of sleep disruption. Nature and Science of Sleep, 9, 151–161.

References

Walker, M. (2017). Why We Sleep. Penguin Random House.
Hirshkowitz, M., et al. (2015). National Sleep Foundation’s sleep time duration recommendations. Sleep Health, 1(1), 40–43.
Van Cauter, E., et al. (2008). Sleep and metabolic function. PLoS Med, 5(3): e57.
Medic, G., et al. (2017). Short- and long-term health consequences of sleep disruption. Nature and Science of Sleep, 9, 151–161.

References

Walker, M. (2017). Why We Sleep. Penguin Random House.
Hirshkowitz, M., et al. (2015). National Sleep Foundation’s sleep time duration recommendations. Sleep Health, 1(1), 40–43.
Van Cauter, E., et al. (2008). Sleep and metabolic function. PLoS Med, 5(3): e57.
Medic, G., et al. (2017). Short- and long-term health consequences of sleep disruption. Nature and Science of Sleep, 9, 151–161.

References

Walker, M. (2017). Why We Sleep. Penguin Random House.
Hirshkowitz, M., et al. (2015). National Sleep Foundation’s sleep time duration recommendations. Sleep Health, 1(1), 40–43.
Van Cauter, E., et al. (2008). Sleep and metabolic function. PLoS Med, 5(3): e57.
Medic, G., et al. (2017). Short- and long-term health consequences of sleep disruption. Nature and Science of Sleep, 9, 151–161.