Drowsiness refers to feeling abnormally sleepy during the day. People who are drowsy may fall asleep in inappropriate situations or at inappropriate times.

Sleepiness - during the day; Hypersomnia; Somnolence

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. But 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)
• Long-term insomnia and other problems falling or staying asleep
• Changes in blood sodium levels (hyponatremia/hypernatremia)
• Medicines (tranquilizers, sleeping pills, antihistamines)
• 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 NOT stop taking or change your medicine without first talking to your provider.

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, and thyroid hormone levels)
• CT scan of the head
• Electroencephalogram (EEG)
• Sleep studies
• Urine tests (such as a urinalysis)

Treatment depends on the cause of your drowsiness.

Chokroverty S, Avidan AY. Sleep and its disorders. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 68.

Hirshkowitz M, Sarwar A, Sharafkhaneh A. Evaluating sleepiness. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 5th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 143.