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The Real Reason You Feel Sleepy in the Afternoon
by Michele Bender

If you’re longing for a latte by 4:00pm, blame your body clock. “A sense of sleepiness can occur seven to nine hours after our wake up time due the brain’s drop in alertness,” explains Fitbit sleep advisor Allison T. Siebern, PhD, consulting assistant professor at Stanford University Sleep Medicine Center and director of the Sleep Health Integrative Program at the Fayetteville VA Medical Center in North Carolina. Another reason you’re feeling fatigued? Your body builds up adenosine, a chemical that accumulates in your system to cause sleepiness, as the day progresses, says Siebern. In other words, the longer you’re up, the wearier you become.

And that’s not all. In the early afternoon, your biological clock sends signals that are similar to (but not as strong as) those it transmits at bedtime. “Most notably, your internal body temperature starts dipping,” explains Michael Grandner, PhD, MTR, a Fitbit sleep advisor and director of the Sleep and Health Research Program at the University of Arizona College of Medicine. “The brain seems to read these drops in body temperature as a signal to conserve energy and prepare for rest and sleep.”

Unfortunately, a mid-day slump can leave you guzzling too much caffeine or reaching for sugary snacks to give you a pick me up.  To avoid potentially unhealthy habits, try these lid-lifting tips instead.


No matter how busy you are, taking a few minutes to head outside into the sunlight can make you more productive. “Getting just 15 to 20 minutes of solid daytime sun (even if it’s cloudy) can send a strong activating signal to the clock in your brain,” explains Grandner. “This can give you an energy boost, especially if you’ve been cooped up all day.” Allowing your eyes to see the sunlight tells your brain it’s time to be awake and alert.


When you’re feeling weary, exercising may be the last thing you feel like doing, but a brisk, 10-minute walk can get your blood and energy flowing. If possible, do this outdoors so you reap the benefits of sunlight along with your stroll. “Or plan to workout right before this afternoon dip typically occurs,” suggests Siebern. This way you get a lift ahead of when you feel you need one. If you can’t spare ten minutes, at least get up from your desk and move around to boost circulation.


Snoozing mid-day isn’t just for the pre-school set. “The human body was built to take a brief rest in the afternoon. So if you can, give it what it wants!” says Grandner. “In fact, data show that even a brief, 20-minute nap can be enough to boost mental and physical performance and meet the need for sleep.” If you’re logistically able to hit the hay, be sure to limit it to twenty minutes, a length of time that should leave you feeling refreshed, not groggy.


It’s okay to sip your favorite coffee drink in the a.m., but limit the amount of coffee, tea, energy drinks, chocolate or coffee-flavored snacks you enjoy after lunch. “Some people are more sensitive to caffeine—and with its long half-life, it could impact that night of sleep,” says Siebern. And if you’re tossing and turning at night, you will be even more tired the next day. That said, everyone is different so it may be trial and error to determine if you can make an afternoon Starbucks run or not.


Think coffee is the only drink that perks you up? Think again. Drinking enough water is another way to get a mid-day lift. “People get tired when they are dehydrated,” explains Grandner. “Staying well hydrated can make you feel more awake and alert.” Aim for the general recommendation of eight 8-ounce glasses of H20—and more if you exercise.


Take a break to chat with someone in person—whether it’s a friend, co-worker, or bank teller. “Some social interaction can help give your mind a break and help it focus on another person. That water cooler conversation may be enough to break up the monotony of your workday,” explains Grandner. Can’t have an in-person conversation? Try FaceTime or a phone call (not a text) to get your social fix.

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This information is for educational purposes only and is not intended as a substitute for medical diagnosis or treatment. You should not use this information to diagnose or treat a health problem or condition. Always check with your doctor before changing your diet, altering your sleep habits, taking supplements, or starting a new fitness routine.