This feeling of exhaustion even has an official name. As Timothy H. Monk, PhD, DSc, wrote in a report for the Western Psychiatric Institute and Clinic of the University of Pittsburgh Medical Center, it’s called the post-lunch dip in performance.

As GetVoIP’s blog explains, if you skip breakfast and then have a large lunch full of carbs, you’re almost guaranteed to experience a post-lunch dip. Yet, some post-lunch dip sufferers may have nothing to blame but their biology.

Your body’s internal clock is its circadian rhythm and there are different types of rhythms called chronotypes. Chronotypes help explain when you feel the most alert and most sleepy. Some people with certain chronotypes might not ever feel tired after lunch (lucky them), but other people feel drowsy particularly from 2 p.m. to 4 p.m. David Dinges, a professor and sleep scientist at the University of Pennsylvania School of Medicine, told The New York Times in 2007 that about 15 to 20 percent of people are “closet nappers,” people who give in to their urge to rest in the afternoon.

Although wanting to snooze during the workday might make you feel lazy, Dinges noted that it’s a natural occurrence and resting when your body wants could help with your overall work performance. Yet, napping during the workday is not a feasible option for many people, so GetVoIP provided some tips on how to boost your energy if you can’t squeeze in a power nap during a break.

The article notes how the three essentials for maintaining energy are to eat well, get enough sleep, and exercise. But you can gain energy at work even if you have been slacking in those departments — and without guzzling an unhealthy energy drink. Although you’d probably feel strange doing jumping jacks at your desk, the article recommends getting your blood pumping. That means you could step out of the office for a quick walk or take the stairs to get the energy flowing. Keep healthy snacks on hand to munch on when you’re fading, and drinking green tea or water will also help. And you can even redecorate your desk with plants to fill your workspace with natural energy. You can find more tips on GetVoIP’s blog that will keep you energized all work day-long.

So while you may never be able to completely control your sleepiness at work, there are ways to ward off those closing eyes to make the most of your workday — no matter your pesky chronotype.