Everyone has days when they feel tired. Maybe you’ve had a few late nights, or you’re stressed at work. A little sleepiness isn’t usually a cause for concern. However, if your sleepiness is affecting your everyday life, it might be time to talk with a doctor to rule out an underlying cause.

About 33%Trusted Source of the U.S. population self-reports living with excessive sleepiness, which is characterized by constant feelings of drowsiness and low energy. Different factors can contribute to excessive sleepiness.

You may have an underlying condition, such as sleep apnea or narcolepsy, that’s keeping you from getting the rest you need. Or, your tiredness may be a side effect of medication or lifestyle choices.

Depending on the cause, excessive daytime sleepiness may not improve on its own. If left untreated, it can interfere with the quality of your life.

Here are a few clues it’s time to seek medical attention for chronic drowsiness.