The most common causes of excessive sleepiness are insufficient sleep, changes to sleep schedule, and sleep disorders like sleep apnea. But if you experience sleepiness on a regular basis, it's important to work with your doctor to rule out some of the other less common causes of sleepiness.
Certain brain and other medical conditions can make a person excessively sleepy. For example, a concussion can cause sleepiness or other disturbances in a person's sleep that result in daytime drowsiness. Neurological conditions such as Parkinson's disease can also cause sleepiness, and psychiatric disorders like anxiety and depression can often cause a person to sleep too little or too much.
Other medical conditions can affect a person's sleep directly, or simply cause enough discomfort to make a full night's sleep difficult. Medical conditions associated with excessive sleepiness include infections, asthma, gastrointestinal disorders, and metabolic abnormalities. In some cases, while people know they have one of these conditions, they don't realize drowsiness is a symptom. In other cases, a person may not be aware of the condition and drowsiness is the first sign.
This is why it's important to take symptoms of excessive sleepiness seriously. Good sleep is critical to your health and your ability to thrive in work, at school, and with your family and friends. Conversely, excessive sleepiness may signal an underlying condition that needs to be addressed and treated. Most of the time, sleepiness can be alleviated by making adjustments to the sleep environment and sleep habits. But sometimes the root of excessive sleepiness is a more serious condition that requires medical attention. If you feel sleepy on a regular basis, bring this to your doctor's attention at your regular well visit, or make an appointment to specifically talk about sleep. You can work together with your doctor to look at your symptoms, sleep and lifestyle habits, and health history to systematically go through all the potential causes of sleepiness and figure out how to help.