Key Takeaways
- You burn about 400-500 calories every night while sleeping for 8 hours. That’s almost the same as your body burns when you’re just sitting quietly during the day.
- Your sleep quality matters. Deep sleep burns fewer calories, but it’s better for your health. When you toss and turn all night, you actually burn more calories. But you’ll feel tired and hungry the next day.
- Age changes things. As you get older, your body naturally burns fewer calories. Poor sleep makes this worse, especially for seniors.
We spend a third of our lives asleep, yet the body never truly powers down. Peer-reviewed calorimetry shows an average sleeper burns hundreds of calories each night—only slightly fewer than at full rest.
Medically reviewed by the Amerisleep Expert Review Board, this guide explains how sleep stages, age, body composition, and bedroom temperature tweak overnight energy use—and offers research-backed tips to optimize both sleep and metabolism.
How Many Calories Do You Burn While Sleeping?
Sleep stages differ not just in brain waves but in how the body conserves energy.
Dr. Stuart Peirson, Circadian Neuroscientist
Whole-body calorimetry
shows
the average sleeper expends ≈ 0.95 × BMR across the night. Deep NREM dips to ~0.88 × BMR, while brief awakenings
can spike
to 1.05 × BMR. For our reference adult, that equals ≈ 420 kcal over eight hours.
Another example is 50–60 calories / hour being what a 154-lb adult
burns
while asleep.
Calorie Burn in Kids & Teens
Dr. Nilong Vyas: Children’s
REM-rich sleep
expends a larger share of daily energy—vital for growth and brain development.
The Brain’s Night-Time Energy Needs
Dr. Jing Zhang: During REM, cerebral glucose uptake rivals
waking levels,
explaining the small metabolic uptick despite
muscle atonia.
Notable Findings
| Topic | Takeaway | Primary Study |
|---|---|---|
| Sleep vs. BMR | Overnight energy expenditure equals basal metabolic rate, though metabolic rate drops significantly below BMR during the deepest sleep periods | |
| Deep vs. REM | REM sleep burns ~4% more calories than deep NREM sleep stages. | |
| Aging | Poor sleep quality in older adults is strongly associated with elevated overnight metabolic rate, suggesting that age-related sleep deterioration may drive higher nighttime energy expenditure. | |
| Sleep Loss | 5 nights × 4 h sleep ↓ next-morning RMR 2.6 % | |
| Bedroom Temperature | Each 1°C core-temp rise ↑ metabolism 7–12% (based on Q10 principles) |
How Sleep Stages & Quality Influence Energy Use
Poor, fragmented sleep keeps your body in an active state—costing extra calories while robbing recovery.
Dr. Jordan Burns, DC, MS
REM sleep burns about 4% more calories than deep NREM. Older adults often experience lighter sleep and more awakenings, with poor sleep quality strongly
associated
with elevated overnight metabolic rate relative to BMR.
Age, Sex & Body Composition
- Age: BMR
drops 4.6%
4.6% from ages 20-30 to 50-65, yet this
observed
decline occurs independent of body composition and activity levels in middle-aged adults. - Sex: Men burn more absolute calories (lean mass), but women show larger appetite-hormone swings
under sleep loss
- Body Composition: Obese individuals
keep
higher absolute burn yet see a faster overnight decline in sleeping metabolic rate.
Hormonal and psychological shifts that accompany aging or stress also affect how our metabolism responds to sleep.
Dr. Colleen Ehrnstrom, PhD, ABPP
Thermoregulation & the Ideal Bedroom Temperature
Temperature and comfort influence sleep posture and muscle recovery, both of which play a role in overnight energy use.
Dr. Jennifer Miller, PT, DPT
Every 1 °C increase in core temperature can raise
can raise
metabolic rate 7–12 %. Sleeping in a 66 °F (19 °C) room
increases
energy expenditure and activates non-shivering thermogenesis. Women in the luteal phase (core T° + 0.3 °C) burned 6.9 % more overnight.
Sleep Deprivation, Hunger Hormones & Weight Gain
Fourteen days of 4-hour sleep restriction
increased
daily caloric intake by 308 kcal without changing energy expenditure, resulting in 0.5 kg greater weight gain and an 11% increase in visceral fat accumulation—the dangerous abdominal fat linked to cardiovascular disease.
Sleep loss increases ghrelin and decreases leptin—two hormones that drive hunger and reduce metabolic control.
Shawna Robins, Nutritionist
FAQs
Does sleeping burn fat?
Sleep burns a mix of carbohydrates and fat; deep, uninterrupted sleep favors slightly more fat oxidation than fragmented or REM-heavy sleep.
How do I calculate my nightly calorie burn?
Use the equation above: BMR × 0.95 × (hours slept / 24), adjusted for sleep quality.
Do colder bedrooms really help?
Yes. A 66 °F bedroom activates calorie-burning brown fat.
Why do I burn more if I keep waking up?
Brief awakenings raise metabolic rate close to waking levels; fragmented sleep therefore expends extra energy—though it harms recovery and hunger hormones.
Do women and men burn calories differently at night?
Women typically burn slightly fewer total kcal (less lean mass), due to the fact that they are overall smaller with men. But women show larger hormonal changes when sleep-deprived. Men’s absolute burn is higher.
Ready to Optimize Your Sleep Environment?
Even when you’re fast asleep, your body is still busy burning calories. What does this mean for you?
- Good sleep is better than burning extra calories. Don’t try to sleep poorly just to burn more energy
- Keep your bedroom cool for better sleep and a small calorie boost
- Focus on sleep quality over quantity – 7-8 hours of solid sleep beats 10 hours of tossing and turning
- Poor sleep makes you hungrier the next day, which can lead to weight gain
The best approach? Get 7-8 hours of quality sleep in a cool, dark room. Your body will burn calories naturally while you rest, and you’ll wake up feeling refreshed instead of tired and hungry.
Remember: good sleep isn’t just about burning calories – it’s about giving your body time to repair, your brain time to recharge, and your hormones time to balance. That’s worth way more than a few extra calories burned from restless sleep.
Methodology
Data sources: Multiple original peer-reviewed studies (1997 – 2024) indexed on PubMed. Only whole-body indirect calorimetry or metabolic-chamber data considered. Reference adult: 70 kg / 154 lb with BMR ≈ 1,500 kcal ⁄ day. Energy-expenditure values normalized to kcal / hour.
