If you’re struggling to get the scale moving in the right direction, the solution could be spending more time between the sheets. “You have to prioritize sleep,” says Dr. Charlene Gamaldo, medical director at the Johns Hopkins Center for Sleep.
Research published in the American Journal of Epidemiology followed 68,183 women for 16 years and found that women who slept fewer than six hours per night had a 32% higher risk of gaining significant amounts of weight — 33 pounds (or more) — than those who slept seven hours per night.
Gamaldo sites three main connections between sleep and weight:
1. SLEEP REGULATES HORMONES
Lack of sleep interferes with levels of the appetite-regulating hormones leptin and ghrelin. Research shows that the less you sleep, the hungrier you’ll feel. One study found that those who slept 4–6 hours per night had higher body mass indexes (BMI) than those who spent 7–9 hours sleeping per night.
Your levels of cortisol, the stress hormone, are also higher when you’re exhausted. “Sleep deprivation is a stressed state,” Gamaldo explains. “Your body feels like it needs to hold on to more calories to survive.”
While one or two sleepless nights won’t throw your hormones out of whack, Gamaldo notes that regularly spending fewer than six hours per night in dreamland triggers hormonal changes that lead to weight gain.
2. SLEEP AFFECTS WILLPOWER
Exhaustion tanks your willpower.
One study found that sleeplessness impaired activity in the frontal lobe, the region responsible for decision making; the reward centers of the brain were activated following one sleepless night and participants showed strong preferences for unhealthy foods like pizza and doughnuts over fruits and vegetables.
“Your judgment is impacted when you’re sleep deprived,” Gamaldo says. “It’s much harder to resist cravings for calorie-rich foods.”
In fact, a 2016 meta-analysis noted that a lack of sleep led study participants to consume an extra 385 calories per day, which could lead to more than one pound of weight gain per week.
3. SLEEP IS A FORM OF FASTING
Research about hormones and willpower aside, Gamaldo notes, “There is a very practical aspect to sleep. You cannot sleep and eat at the same time. For every hour you’re sleeping, you’re not eating or snacking.”
Despite the strong connections between sleeplessness and weight gain, more than 35% of adults sleep for fewer than seven hours per night and the National Sleep Foundation reports that 45% of Americans blamed poor or insufficient sleep for interfering with their daily activities.
To get a better night’s rest, Gamaldo suggests shutting down electronics an hour before bed; maintaining a bedtime routine that could include a warm bath and putting on a favorite pair of pajamas; and establishing a regular sleep/wake time.
“If you’re sleeping fewer than six hours per night — that’s the magic number — more than a couple of times a week, there are reasons to be concerned,” Gamaldo says. “Tonight is as good a night as any to prioritize getting your rest and start reversing the impact of not getting enough sleep.”
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