woman with head on kitchen counter, pouring coffee and missing mug | causes of feeling tired all the time
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“I make sure to get enough sleep, but I still always feel tired. Why could this be?”

—Ariel B., Red Rocks Community College, Colorado

This is a very common dilemma. It can be helpful to determine whether you’re experiencing fatigue, somnolence, or a combination of both.

  • Fatigue means that you get tired more easily doing physical activity—even day-to-day activities, such as walking and climbing stairs—and that you just don’t have your usual energy supply.
  • Somnolence means that you’re sleepy and can fall asleep readily at times other than bedtime.

These are two different problems with two different sets of possible causes.

Some people can’t really distinguish whether they’re fatigued or somnolent. That’s OK, too. It just makes it less likely that there’s a single identifiable cause.

If you’ve been feeling unusually tired for two weeks or less, the list of possible causes is different than if it’s a long-standing problem.

So what are the possible causes? Sometimes we can identify a single cause, but most often there are a combination of factors. Here are some:

Poor sleep quality

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Many students overestimate the amount and quality of sleep they get. If you’re someone who needs nine hours a night and are consistently getting closer to seven, and those seven hours are on a variable schedule (sleeping in or waking early depending on that day’s schedule), you’re accumulating sleep debt.

The more sleep debt you accumulate, the groggier you feel. Chronic sleep debt can lead to poor concentration, decreased capacity for learning, increased risk of getting sick, decreased athletic performance, and more.

Aim for a consistent sleep schedule. Get up at the same time every day, and don’t sleep more than an hour later on weekends. (This is usually easier than going to bed at a consistent, early bedtime, and helps reset your body clock.)


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Taking vitamins or other supplements is unlikely to provide a benefit for your tiredness. Most of us get the nutrients we need from our diet. Rarely, malabsorption (the inability to absorb essential nutrients from foods because of a problem with the function of the gut) can cause fatigue. There are usually accompanying symptoms that a clinician can identify.


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Another common cause of feeling tired all the time is depression. Classic symptoms include anhedonia, the inability to take pleasure in things that used to be enjoyable, and hopelessness or feeling like there’s no point to getting out of bed in the morning. If this seems familiar, make an appointment with your school counseling center.


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One potential cause of increased fatigue among college students is mononucleosis (Epstein Barr virus infection). Mono is usually transmitted by saliva, like colds and many other viral infections. It often causes a terrible sore throat but sometimes presents as fatigue only. People typically complain of feeling drained, of needing to take long naps, and of diminished ability to exercise. Other illnesses, as well as certain medical conditions such as sleep apnea, can also cause fatigue. Sorting through the possibilities may take a few doctor visits and some lab testing.

When to seek help

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If you feel tired all the time, especially if the symptoms have lasted more than a week or are accompanied by other symptoms such as fever, diarrhea, rash, sore throat, cough, etc., contact your primary care provider or school health center and schedule an evaluation. This is especially important if the symptoms are hampering your academic, athletic, or social pursuits, or are otherwise getting in the way of your life.