Body clock: Best times to eat, sleep and exercise

  • Article by: ALLIE SHAH , Star Tribune
  • Updated: July 21, 2013 - 9:10 AM

Want to maximize your health? Here are the best times to eat, sleep, exercise – and do everything else.


An analog Minerva stopwatch

Photo: Carlos Gonzalez, Star Tribune

CameraStar Tribune photo galleries

Cameraview larger

When it comes to healthy living, there’s no shortage of competing views on how to fight flab, run faster, sleep sounder and feel happier.

But what if when you exercise — and eat and sleep — is just as important as how?

Mounting evidence suggests that our bodies perform differently at different times of the day. Like all living things, we have an internal clock that affects our hormonal responses, body temperature, heart rate and sleep cycles. It’s determined by something called circadian rhythms, which follow the 24-hour pattern of the Earth’s rotation.

Does this sound a bit mystical? Maybe. But health experts say knowing your body’s clock can help you synchronize your daily activities for optimal health. Mastering these internal rhythms can pay dividends — from controlling your weight to sleeping better to improving your overall mood.


“Whether you are a yeast in beer or a fly or a dog or a fish, we all have this innate 24-hour circadian rhythm,” said Dr. Michael Howell, a neurologist at the University of Minnesota. “What your body is doing at 8 o’clock in the morning is different than what your body is doing at 10 o’clock in the morning. Your gut responds differently to food at different times of the day, and we have different capacities for exercise at different times of the day.”

What happens if you disrupt these natural rhythms? You might be setting yourself up for a host of health problems.

The well-timed sleep

For many people, a good night’s sleep is the hallmark of optimal health.

There’s no perfect time to wake up, Howell said, because sleep cycles vary dramatically from person to person. But finding the time when you naturally wake up is crucial to getting good rest. Sleep problems more often stem from mistimed sleep than from anything else.

Nighttime, Howell said, isn’t the only time our bodies crave sleep. Our energy level and body temperature takes a natural dip in the middle of our waking day, making us tired. Before industrialization, most people did not work a conventional eight to nine hours in a row without pausing for rest, he said.

Although most modern work schedules do not make it possible to accommodate a midafternoon power nap, the most refreshing sleep comes from having slept six hours at night and then napping for up to two hours in the afternoon, Howell said.

Nap times vary, depending on when you get up in the morning. “It’s usually 6 hours after your normal wake-up time,” he explained, “so if you wake up at 7 a.m. then your natural time to fall asleep is at one in the afternoon.”

Fitting in fitness

Martha Mattheis, a lawyer from Carver County, is an avid long-distance runner and has completed 17 marathons. She enjoys running in the morning, but has tried running at different times of the day.

She’s made a discovery: “I think I run faster in the afternoon,” she said, “because I am warmed up and I’ve had quite a load of caffeine on board.”

Some physiologists back up the idea that afternoons are the perfect time to tackle high-intensity exercise.

“That’s because you have the day to warm up as opposed to waking up with stiff joints, and blood flow [in the morning] might not be quite what it is at the end of the day,” said Paul Mellick, assistant professor in the Department of Health and Human Performance at the University of St. Thomas.

  • related content

  • The body clock-driven day

    Saturday July 20, 2013

    Getting our daily habits in sync with our natural body clock can help us live healthier. We culled advice from...

  • get related content delivered to your inbox

  • manage my email subscriptions


Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters