Are you sleepy or just tired?

The mortal urge for sleep frequently hits at the most inopportune times: on your commute to work, during the post-lunch slump, the exact moment you should depart in order to make it to an exercise class on time. The simple act of getting some shut-eye isn’t necessarily the best remedy for each of these bouts of languor. That’s because each lethargic experience isn’t created equally. In some instances, you may be feeling “sleepy”; in others, you may be “tired.”

There are different underlying reasons for both sleepiness and tiredness — and different ways they manifest in the body. It’s important to know the difference between the two “because they’re addressed differently,” says Abhinav Singh, a medical review expert at SleepFoundation.org and the medical director of the Indiana Sleep Center. “Sleepy and tired are just like hunger and thirst. Can they be close to each other? Sure they can,” he says. “But they are quenched by different things, like hunger with food, thirst with water.” There are ways to address sleepiness and tiredness, experts say, but first you need to know which sensation you’re experiencing.

Sleepiness is marked by drowsiness and a strong desire for sleep, says Shelby Harris, a clinical psychologist who specializes in behavioral sleep medicine. Signs of sleepiness include heavy eyelids, frequent yawning, nodding off, blurred vision, impaired coordination, slowed thinking, and increased irritability, Harris says. Sleepiness is caused by lack of sleep or poor sleep due to insomnia or sleep apnea or even being up all night with a sick toddler.

On the other hand, tiredness or fatigue is “a state of physical or mental exhaustion that typically comes along with a lack of energy,” Harris says. Tiredness can present with a heavy and weary sensation in your body, but you feel cognitively tapped out, too. Mental and emotional stress — say, from a long day at work — can make you tired. So can physical exertion, medical conditions like anemia or diabetes, or recovering from an illness, like the flu, says Beth Malow, the director of the Vanderbilt Sleep Division at Vanderbilt University Medical Center.

The inevitable “cure” for sleepiness is sleep. However, fatigue is usually not abated by sleep. You can be tired from a hard workout but won’t drift off to sleep if you sit down for a few minutes afterward. “I’m just so achy, I’m so tired all over — that’s fatigue,” Malow says. “While sleepiness is more about you’re apt to fall asleep, anytime, anywhere.”

It is possible to be both sleepy and tired, Singh says. If you’re sleeping only five hours a night and overextending yourself at work and socially, you can end up with an exhausting mix of both sensations. Symptoms include irritability, difficulty focusing, making mistakes at work, and increased hunger. If you find yourself canceling plans to stay in and watch TV to recuperate, only to fall asleep on the couch after a few minutes, that’s a sign you’re both sleepy and tired, Singh says.

To determine whether you’re tired or sleepy, you have to look at what is causing your desire to crawl into bed. When you wake up in the morning, evaluate how you slept, Singh says: Did you get the advised seven to nine hours of sleep? Were you uninterrupted during that time, or did you toss and turn or periodically wake up? If you share a bed with a partner, they can fill you in on whether you were restless overnight, snored, or slept soundly. Interruptions to your sleep will make you sleepy.

Another way to determine if you’re sleepy is to use the Epworth Sleepiness Scale, Malow says, where you can rank your likelihood of nodding off during activities like watching TV or as a passenger in a car. A score of 10 or higher indicates you need to get more sleep or higher-quality sleep.

Homing in on the underlying cause of tiredness is more difficult, since there are many contributors to fatigue, from side effects of medication to a day of back-to-back meetings. “I truly believe that people can feel fatigued from interacting with people all day and you hit this limit,” Malow says. In those situations, you may be tired, but not ready for bed and just want some time alone.

For ongoing bouts of fatigue, you’ll want to check with your doctor who’ll do tests to determine if you have thyroid disease, anemia, hormone imbalances, or infection. “Fatigue is more medical,” Malow says, “and sleepiness is more of a sleep disorder.” If you don’t have a primary care doctor or haven’t been to one in years, check your insurance carrier’s website for a physician in your area that’s accepting patients. If you don’t have insurance, free clinics or federally qualified health centers in your area provide medical care for no or low cost.

The most straightforward remedy for sleepiness is, well, to get some sleep. Try to squeeze in a 5- to 10-minute power nap if you can, Malow says. Parents of newborns or kids with irregular sleep patterns won’t be able to prioritize uninterrupted nights of sleep, but try to fit in a nap when time allows.

Many schedules don’t allow for midday snoozes. Harris suggests physical activity, like stretching, light exercises, or a walk outside, to help wake yourself up. If there are factors impacting your sleep — say you wake up frequently throughout the night or snore — you may want to seek out a sleep specialist, Malow says, who can help diagnose any sleep disturbances and treat you for them. You can find a sleep specialist by asking your primary care doctor for a referral or you can search through your insurance provider’s list of covered physicians online. The American Academy of Sleep Medicine also maintains a directory of sleep specialists and facilities.

Check with your insurance carrier to determine how much the appointment will cost, if it’s covered, or if you have to hit your deductible before they’ll provide a copayment. Depending on where you live, whether you have insurance, and if you’re doing a sleep study at home or in a lab, a sleep study can cost anywhere from $150 to $10,000, so make sure to ask about prices before booking any appointments or procedures.

For sporadic bouts of fatigue that aren’t influenced by underlying health issues, Harris suggests taking regular breaks at work, school, or in between tasks, getting exposure to natural light (especially in the morning), and staying hydrated. Any way you can lighten your mental load if your energy is zapped will help rejuvenate you. “Sitting down and resting and doing something that minimizes your energy load is really good,” Malow says. “Maybe not interacting with other people for 30 minutes or being able to put your feet up.”

Should none of these options ease your fatigue and you suspect a health issue is at play, Singh and Malow recommend seeking the help of a medical professional who can work with you to determine if you need a tweak in your nutrition, level of physical activity, or require medication to correct an imbalance.

“Everybody experiences tiredness and fatigue in different ways: Some people become more irritable, crabby, some people become more lethargic, some people become more forgetful,” Singh says. “It’s tough to say that everybody’s going to feel it in this algorithmic way. It’s very non-algorithmic when it comes to causes and treatment.”