Want to get fitter in the gym? Maybe you need to think outside the gym, literally.
She trains an eclectic group of women—stay-at-home moms to competitive athletes—and once they establish a sleep routine, results follow.
That's because adequate sleep triggers testosterone, which builds muscle, while not sleeping enough can spur a release in cortisol, the hormone that breaks down muscle, says Christopher Winter, M.D. who studies the link between fitness and sleep.
Here are a few tips for keeping yourself fitter and far from fatigue.
Your body pumps out the majority of the strength- and muscle-building hormone testosterone during the first three hours of your regular sleep pattern, says Winter.
Miss that window and, even if you log eight hours, you still lose the night's most important muscle-building moment.
First establish a consistent sleep schedule—go to bed at 10 and wake at five or six, for example.
Then stick to it, limiting your late nights to a few a month.
Find out the best way to get a better night's sleep:
That 7 p.m. boot-camp class not only helps you pack on lean muscle but is also a fun way to work off the day's stress.
The problem: It amps your central nervous system for hours. "You can't immediately go from 100 to zero," says MacDonald.
"If you don't establish a routine to relax each night, your sleep will suffer."
An hour before bed, take a bath and read a book, says MacDonald.
Then instead of reaching for a glass of pinot, try a protein shake. Alcohol can interfere with your ability to sleep, says Winter, while protein gives your body muscle-building blocks, says Krista Scott-Dixon, Ph.D., a nutritionist at Precision Nutrition.
Even the faintest light can blunt the release of the sleep hormone melatonin, says Winter.
With that in mind, MacDonald has all her clients turn their bedrooms into modern-day Paleolithic caves.
"If you draw the shades and turn out the lights, you shouldn't be able to see anything," she says.
Hang light-blocking curtains over your windows and remove electronics like TVs and computers—their LED blue lights are particularly gnarly sleep saboteurs, according to a study in Proceedings of the National Academy of Sciences.
Can't be far from your phone? Put it facedown or in "do not disturb" mode.
This article originally appeared in the June 2017 issue of Women's Health. For more great advice, pick up a copy of the issue on newsstands now!