Too much sleep

Our bodies have what is called a circadian rhythm, which is basically a 24-hour cycle of biological and mental processes. According to the National Institute of General Medical Sciences, circadian rhythms are driven by our biological clocks, but are also influenced by our environment with light being a major factor. When your body is in an environment with little light, it signals the production of melatonin in the brain, which makes you sleepy. It also works in reverse; the presence of light will trigger you to  wake. People who suffer from jet lag or shift work disorder experience a disruption of their circadian rhythm.

We know that getting too little sleep is bad for our minds and bodies, but is getting large amounts of sleep better? Getting a good 7-9 hours of sleep is a challenge for most people, and the luxury of taking naps is something most of us can't afford. Just as getting too little sleep can lead to many health problems, getting too much sleep is also bad. Many of the same ill effects can be seen if you get too much sleep compared to too little. Increased risk of depression, obesity, and even diabetes have all been linked to inappropriate amounts of sleep. Oversleeping can have other short-term side effects like headaches or even fatigue, but adhering to a schedule that promotes healthy sleep according to your circadian rhythm and practicing good sleep hygiene (see image) can easily prevent you from sleeping too much. For people with sleep disorders, regulating sleep is much harder.

Sometimes excessive sleepiness can be caused by depression, medication, or even head injuries, but there are also some disorders that cause excessive sleepiness. There is a simple test called the Epworth Sleepiness Scale (ESS) - as described by Murray W. Johns - that can provide a measure of a person's general level of sleepiness and may help in diagnosing excessive sleep disorders. Narcolepsy and Idiopathic Hypersomnia are two such disorders.  Narcoleptic people experience cataplexy which is a sudden extreme "sleep attack" that involve loss of muscle control and are involuntary and irresistible. These attacks last about 15 minutes and have a refreshing effect on the person. This sudden muscle weakness is sometimes caused by strong emotion or surprise, and excessive daytime sleepiness is also symptoms of narcolepsy. An article in the Annual Review of Genomics & Human Genetics says that there is a 20-40 times increased risk of being diagnosed with narcolepsy if you have a first degree relative with the disease.

Idiopathic Hypersomnia literally means sleeping too much without a cause. Individuals who suffer from this disease also suffer from many of the same problems that narcoleptic people do, but do not experience cataplexy and do not feel rested after naps or after a full 7-9 hours of sleep. Those who have idiopathic hypersomnia sleep up to 14-18 hours a day, and continue to feel extremely drowsy when awake.

With both of these disorders, quality of life is diminished. Anxiety, depression, lack of energy, loss of appetite, and troubles with memory are some of the difficulties they face. In some cases, especially for those who are narcoleptic, simple tasks like driving or working are virtually impossible. If you think you may be sleeping too much on a regular basis, seeing your doctor should be a priority.

Citation:

• Chabas D, Taheri S, Renier C, Mignot E. THE GENETICS OF NARCOLEPSY. Annual Review Of Genomics & Human Genetics [serial online]. September 2003;4(1):459-483. Available from: Science & Technology Collection, Ipswich, MA. Accessed November 26, 2012.
• Johns, Murray W. "A New Method for Measuring Daytime Sleepiness: The Epworth Sleepiness Scale." Sleep 14.6 (1991): n. pag. American Sleep Disorders Association and Sleep Research Society, 1991. Web. 26 Nov. 2012. <http://epworthsleepinessscale.com/wp-content/uploads/2008/12/a-new-method-for-measuring-daytime-sleepiness-the-epworth-sleepiness-scale2.pdf>.