Maybe you’re going through a particularly grueling period at work ― think tons of deadlines, responsibility on a major project or battling for a promotion. Simultaneously, you’re also feeling exhausted as hell.

Most people associate stress with feeling wired. But stress and fatigue also go hand in hand. It’s actually fairly common to feel the need to fall asleep when you’re incredibly high-strung, although nothing has been definitively confirmed in scientific literature as to why.

Experts do have some theories, however. Stress frequently impacts your sleep cycle, said Deirdre Conroy, clinical director of the Behavioral Sleep Medicine Clinic at Michigan Medicine’s Sleep Disorders Centers.

“When we’re under a lot of stress, the continuity and quality of the sleep can be affected,” Conroy said. “It might take longer to fall asleep, or we might have frequent or sustained awakenings during the night after we have fallen asleep.” Broken sleep can increase your feelings of fatigue during the day.

Stress can also interfere with the quality of sleep while you’re out, leading to “a higher percentage of light stages of sleep across the night,” according to Conroy. Since your body typically recharges during periods of deeper sleep ― repairing tissue, resting muscles and boosting immunity ― you might feel like you’re not getting enough sleep.

You might also experience standard insomnia some nights, which will make you feel poorly rested.

“Stress is a well-known contributor to insomnia,” said Aric Prather, an associate professor in the Department of Psychiatry and Weill Institute for Neurosciences at the University of California, San Francisco.

“Stress exposure can lead to more cognitive arousal, like rumination about what happened, and so on,” Prather continued. “Related to this, it’s thought that stress likely leads to increased activation of the sympathetic nervous system ― the fight-or-flight response ― and this can impair your ability to relax.”

When Stress Leads To Extreme Fatigue

Sleepiness is one thing, but some people experience intense fatigue during periods of high stress to the point where it can be debilitating. Experts have a few theories as to why, the first being that the fight-or-flight response simply taxes the body’s energy levels.

“Because it is so metabolically expensive to keep the body on high alert, sleepiness may occur so that the body can replenish that energy,” Prather said.

Others think that sleep is a coping mechanism for stress, because it can be so exhausting and unpleasant.

“Under periods of stress, many people choose to spend excess time in bed, and often fall asleep, as a way of escaping from the stress,” Prather explained. “Because sleep, at least in the short term, can provide some relief from the distress, sleeping behavior can be reinforced.”

Prather said that if you consistently use sleep as a means to escape stressful life periods, wanting to climb into your covers can become increasingly hard to resist ― and habitual.

The last theory is that your brain simply can only handle so much stressful content.

“There’s the possibility that the brain can only hold so much emotional information, and sleep helps clear some space and help figure out which daily experiences need to be put in long-term memory storage and what can be discarded,” Prather said. “Stress can produce high-arousal emotional information, and thus sleep may be needed earlier than usual.”

How To Handle Sleepiness When You’re Stressed

First and foremost, if you’re unsure whether your sleepiness is normal, you should get it checked out by a doctor.

“Routine blood tests collected at a doctor’s visit are very important if you are experiencing chronic symptoms of insomnia,” Conroy said. “Abnormal levels of hormones, like thyroid-stimulating hormone, can affect how we feel during our waking hours.”

Conroy also said to pay attention to your diet and fitness regimen. Skipping workouts and loading up on high-sugar or high-carb meals may make you sleepy or lead to an energy crash.

“Make sure you are drinking enough water, and have a regular exercise routine,” Conroy said.

You can also eliminate fatigue when you’re stressed by pacing your activities during your waking hours.

“Don’t overdo it or underdo it,” Conroy said. “Engage in some form of relaxation, and paying attention to avoid unhelpful thought patterns.” Thinking, “I’m never going to finish this,” or, “I am way too busy to take time out for myself” is going to keep you in the same, tired cycle.

Prather said that you should make sure to carve out some “me” time ― no matter how many deadlines you have, or how big the project.

“Stressors can feel all-consuming, but they don’t have to be,” Prather said. “Scheduling things that you enjoy, like yoga or getting out in nature, can be really revitalizing and stress-reducing.”

Yes: That midday break might help you go longer and be sharper. Prather said there’s “no sense ignoring how your body is feeling,” as it won’t go away by continuing to push yourself. Rest. Then, get back to it.