I don’t know about you, but when 3 o’clock or so hits, nothing feels better than getting under the covers. Just as my motivation to get anything productive done hits its daily low, it seems like I suddenly can’t stop yawning. Yet, at the same time, I know all too well that a nap might backfire when I’m trying (and sometimes failing) to fall asleep later that night.

Feeling like I need a nap almost daily surely means something’s wrong, right? Here’s what a sleep expert has to say.

Why you may want to nap daily

Regularly craving your pillow in the middle of the day can be a signal that you’re overworking your body or have an emotional or physical problem at hand. While there are many possible causes, ranging from depression to a chronic illness, some of the main ones include:

1. Inadequate sleep

While this one sounds a bit obvious, you may not realize how much it’s at play. Sleeping a few hours and tossing and turning are only part of the equation. “You may be getting enough restful sleep at night, but the amount of work and the intensity of the work that you’re doing during the day is too high to match the amount you’re recovering at night,” explains Dave Rabin, MD, PhD, a neuroscientist, board-certified psychiatrist, co-founder and chief innovation officer at Apollo Neuroscience, which has developed the first scientifically-validated wearable technology that’s meant to support sleep.

Everything from moving throughout our day, to thinking, stressing, breastfeeding, and, you know, staying alive through organ functioning requires substantial energy. Your body is working harder than you probably realize! Plus, all bodies have different needs: While six or seven hours a night may cut it for your friend, you may need eight to 10.

2. Nutrient deficiencies

While carbs, fat, and sugar are important parts of your diet, they can also cause tiredness. “These kinds of foods can actually cause a quick ramping up of energy in the body, which can be very stimulating but can also result in a crash afterwards,” Dr. Rabin says. Protein, on the other hand, is more likely to give you sustainable energy, he adds.

Additionally, lacking iron, vitamin B12, and vitamin D can leave you feeling zapped. If you think this might be behind your afternoon snooze, try to incorporate more dairy products, red meat, eggs, rice, beans, fish, and orange juice into your diet. Additionally, having a bedtime snack with fiber, magnesium, and/or melatonin is a smart idea to get solid hours at night.

Eating foods your body doesn’t like can hurt you, too, even if you’re not full-blown allergic. “When you’re lactose intolerant…what happens is the lactose gets passed down to your gut and actually takes a large toll on the gut and inflames the inner gut lining, which then prevents the absorption of other nutrients and other foods,” Dr. Rabin explains. “So, we are not absorbing nutrients as well, which means our bodies are spending more energy to work through the inflammation and still not picking up as much energy when they pull in the nutrients.”

3. Caffeine tolerance

Your cups of black coffee may not do you the perking-up favors you’ve heard it does, either. “People who drink caffeine all the time can become very tolerant to it,” Dr. Rabin says. “When I was in medical school, I drank so much coffee that it was becoming the opposite of helpful. I would have a cup of coffee and immediately I would feel tired.”

Research backs this up. According to a report in Sleep Medicine Reviews, studies have shown that regular caffeine intake is associated with disturbed sleep and daytime sleepiness. “The risks to sleep and alertness of regular caffeine use are greatly underestimated by both the general population and physicians,” the abstract reads.

4. Mental or physical health conditions

Lastly, various health conditions—such as depression, hypothyroidism, and multiple sclerosis (MS)—can impact your napping habits in various ways, too, Dr. Rabin notes.

• Depression: “One of the main reasons why people who have depression may be sleeping all the time is because they don’t have the motivation to engage in their normal activities since they don’t get fulfillment out of these things,” Dr. Rabin explains. That daily nap could be a distraction from reality, or “something to do” when nothing else interests the person.
• Hypothyroidism: The thyroid is very important to regulating energy in the body, Dr. Rabin says, and hypothyroidism means the thyroid hormones are low. “If the body is driven by low thyroid hormones, which impacts metabolism, the metabolism slows down. This is a big part of why people feel more tired,” he says.
• MS (and other chronic conditions): Similar to other autoimmune illnesses, MS can take a toll on your body. “We try to combat and help to do things to give people more energy, but generally speaking, folks with chronic inflammatory diseases do end up sleeping more because those conditions are very taxing on the body,” Dr. Rabin says.

These are only a few examples. If you have a mental or physical health condition and are worried it could be causing your daily nap, consider talking to your health provider.

What to know about the effects of a daily nap

While naps can be a sign that something is up with your body, they aren’t all bad. (Phew). Dr. Rabin says a power nap as short as 20 minutes can replenish energy, and one close to 90 minutes (or an entire REM cycle) can be helpful, too. In other words, there’s no need to feel bad about taking an afternoon snooze.

What you want to be wary of, though, is if it’s messing with your daily life or signaling another issue at hand. Dr. Rabin points to too much sitting, drinking too much caffeine or alcohol, and not getting enough of the right nutrients, to start. He encourages optimizing those areas.

“Again, napping daily isn’t necessarily a bad thing if that’s a choice that you’ve made to do, but it’s important to understand why you’re making that choice,” he says.

And hey, remember that people of some cultures nap every afternoon—aka “siestas”—which can improve your memory, reasoning, endurance, heart health, and stress levels, to start.

Best napping practices

Few things are quite as frustrating as catching up on sleep with a nap, only to have it mess with your nighttime sleep cycle, leaving you awake at 2 a.m. What’s the best strategy for getting all the benefits without it coming back to bite you?

Dr. Rabin recommends getting your nap in before 3 p.m. or 4 p.m. (or at least four to five hours before your bedtime). He also suggests sleeping no longer than 90 minutes, max. “Once our nap starts to get longer than 90 minutes, it starts to fool our body into thinking that we’re in a sleep cycle. (Even 90 minutes could be pushing it),” he says.

These rules aren’t hard and fast for everyone, though. “I know people who can nap at any time and can still go to bed at night just fine, and I know people that can’t, so it’s a very, very personal thing,” Dr. Rabin says.

Ultimately, if you enjoy a daily nap that makes you feel better, great! But if it comes alongside stress, self-medication, or restless nights, you may want to look into alternatives, and make sure there’s nothing serious that’s sapping your daily energy.

“If we don’t do anything about the root cause issue, it can really throw off our circadian cycles and make things challenging for us,” Dr. Rabin adds. “It’s very important to think about why we’re napping and why we’re forming patterns around napping, because this will help us understand how to get the most out of naps, sleep, and energy levels.”