Excessive daytime sleepiness (without a known cause) may be a sign of a sleep disorder.

Depression, anxiety, stress, and boredom can all contribute to excessive sleepiness. However, these conditions more often cause fatigue and apathy.

Drowsiness may be due to the following:

• Long-term (chronic) pain
• Diabetes
• Having to work long hours or different shifts (nights, weekends)
• Insomnia and other problems falling or staying asleep
• Changes in blood sodium levels (hyponatremia or hypernatremia)
• Medicines (tranquilizers, sleeping pills, antihistamines, certain painkillers, some psychiatric medicines)
• Not sleeping long enough
• Sleep disorders (such as sleep apnea and narcolepsy)
• Too much calcium in your blood (hypercalcemia)
• Underactive thyroid (hypothyroidism)

You can relieve drowsiness by treating the cause of the problem. First, determine whether your drowsiness is due to depression, anxiety, boredom, or stress. If you are not sure, talk with your health care provider.

For drowsiness due to medicines, talk to your provider about switching or stopping your medicines. But, do nots stop taking or change your medicine without first talking to your provider.

Do not drive when drowsy.

Your provider will examine you to determine the cause of your drowsiness. You will be asked about your sleep patterns and health. Questions may include:

• How well do you sleep?
• How much do you sleep?
• Do you snore?
• Do you fall asleep during the day when you do not plan to nap (such as when watching TV or reading)? If so, do you awake feeling refreshed? How often does this happen?
• Are you depressed, anxious, stressed, or bored?
• What medicines do you take?
• What have you done to try to relieve the drowsiness? How well did it work?
• What other symptoms do you have?

Tests that may be done include:

• Blood tests (such as a CBC and blood differential, blood sugar level, electrolytes, calcium, and thyroid hormone levels)
• CT or MRI scan of the head
• Electroencephalogram (EEG)
• Sleep studies
• Urine tests (such as a urinalysis)

Treatment depends on the cause of your drowsiness.

Sleepiness - during the day; Hypersomnia; Somnolence

Avidan AY. Sleep and its disorders. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 101.

Sharafkhaneh A, Hirshkowitz M. Evaluating sleepiness and fatigue. In: Kryger M, Roth T, Goldstein CA, Dement WC, eds. Principles and Practice of Sleep Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 207.

Vaughn BV, Basner RC. Sleep disorders. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 374.

Updated by: Linda J. Vorvick, MD, Clinical Professor Emeritus, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.