Let’s jump right in.
Total energy expenditure, the way our body uses calories, can be split into three main components:
1. The body’s resting metabolic rate (RMR); the energy we burn simply by existing, breathing, pumping blood, sleeping etc.
2. The body’s thermic effect of feeding (TEF); the energy we burn by eating and digesting food and drink.
3. The body’s thermic effect of activity (TEA); the energy we burn by exercise.
Given that RMR makes up 60-70% and is the largest component of our body’s total energy expenditure, science did a deep dive at the relationship between sleep and RMR.
The results suggest that in healthy adults, sleep restriction can have a considerable impact on our overall metabolism. This means that when we restrict sleep, it prompts our body to make changes to conserve energy (slow down the metabolism), making it more difficult for us to burn calories.
Sleep restriction can also make us eat more. This is because our body needs to get the fuel for it to function from somewhere! The fuel that our body would normally get from a restorative sleep is made up for by consuming extra calories in food. The combination of a longer awake period to eat more, and the result of lower metabolic rate from less sleep, puts adults who are habitually short sleepers at a higher risk for weight gain and obesity.
Have you been getting enough sleep? This study showed that after restricted sleep (6 hours or less) for 3 weeks, RMR returned to baseline levels after 9 nights of recovery sleep (10+ hours). If you’ve been getting some short nights, give yourself some nights to recover and get that RMR back to your baseline!
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Science, Feminism and Love.
Spaeth AM, Dinges DF, Goel N. Resting metabolic rate varies by race and by sleep duration. Obesity (Silver Spring). 2015 Dec;23(12):2349-56. Epub 2015 Nov 5.
Spaeth AM, Dinges DF, Goel N. Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults. Sleep. 2013;36(7):981-990. Published 2013 Jul 1.
