Excessive Daytime Sleepiness: Why You Nod Off and What a Visit Can Find

What it involves

MedlinePlus defines drowsiness as feeling more sleepy than normal during the day, and says people who are drowsy may fall asleep when they do not want to, which can lead to safety concerns. It says excessive daytime sleepiness without a known cause may be a sign of a sleep disorder.

Who this is for

• Adults who fall asleep while reading, watching TV or sitting in meetings
• Patients who sleep a full night but wake unrefreshed
• People whose partner says they snore loudly or stop breathing in their sleep
• Drivers and shift workers who feel dangerously drowsy

What to expect

• Questions about how long and how well you sleep, whether you snore and whether you wake refreshed
• A review of medicines, alcohol use, work schedule, mood and other symptoms
• Blood tests that can include a blood count, blood sugar, electrolytes, calcium and thyroid levels
• A referral for a sleep study if the picture points to a sleep disorder

Sleepy versus tired

The MedlinePlus drowsiness article draws a useful line. Depression, anxiety, stress and boredom can all contribute to excessive sleepiness, it says, but they more often cause fatigue and apathy. Being sleepy means you could drop off if you sat still, while being fatigued means you feel worn out but could not sleep. The fatigue and tiredness guide covers the second pattern, and telling your provider which one fits you best points the evaluation the right way.

Common causes, as MedlinePlus lists them

MedlinePlus lists long-term pain, diabetes, long or changing work hours, insomnia, changes in blood sodium, sedating medicines such as sleeping pills and antihistamines, not sleeping long enough, sleep disorders such as sleep apnea and narcolepsy, high blood calcium and an underactive thyroid. The encyclopedia article on sleep disorders adds obesity that causes obstructive sleep apnea, fibromyalgia, viral illnesses such as mononucleosis and sedating medicines. That is a wide list, and a visit narrows it using your history and tests.

Sleep disorders in plain language

MedlinePlus says there are more than 100 sleep disorders, grouped into problems falling or staying asleep, problems staying awake, problems keeping a regular sleep schedule and unusual behaviors during sleep. Hypersomnia is the one marked by excessive daytime sleepiness. Sleep apnea, where breathing stops or gets very shallow during sleep, often shows up as loud snoring and daytime drowsiness, and the sleep apnea guide explains it. The insomnia guide covers the opposite problem, trouble falling asleep.

Medical conditions that hide behind sleepiness

Not every sleepy patient has a sleep disorder. An underactive thyroid, diabetes, a blood sodium or calcium imbalance and low blood counts can all leave a person dragging through the day, and the MedlinePlus list of tests for drowsiness includes a blood count, blood sugar, electrolytes, calcium and thyroid hormone levels. Restless sleep from other conditions matters too, and the restless legs guide and the fibromyalgia guide each describe conditions that fragment sleep.

What to bring and what the visit covers

MedlinePlus says the provider will ask how well and how much you sleep, whether you snore, whether you fall asleep when you do not plan to nap, and how you feel when you wake. Questions also cover mood, medicines and what you have already tried. A sleep diary for two weeks, a list of everything you take and a bed partner's description of your nighttime breathing make the visit far more useful. Treatment depends on the cause, and MedlinePlus says to talk with your provider before changing or stopping any medicine.

Safety first

MedlinePlus is direct on one point: do not drive when drowsy. If you have nodded off at a red light, drifted out of your lane or had a near miss, tell your provider at the first visit and avoid driving until you have been evaluated. Sudden sleepiness with confusion, slurred speech, weakness on one side or a severe headache needs 911 rather than an appointment. Daytime sleepiness that has built up over weeks or months is a good reason to book a visit this week.

Sources

• MedlinePlus: Drowsiness (medical encyclopedia)
• MedlinePlus: Sleep disorders (medical encyclopedia)
• MedlinePlus: Sleep Apnea (health topic)