It is estimated that 12 million people in Germany suffer from daytime sleepiness. If daytime sleepiness is persisting over a longer period of time, then there is a good chance that the individual may suffer from a sleep disorder. It is not always obvious whether sleepiness may be simply related to a sleep deficit. Sleep deprivation is a common problem in our highly industrialized societies. So, if you suffer from unexplained daytime sleepiness or even from unintentionally falling asleep during the daytime, you should see a sleep specialist.
Since the field of sleep medicine is a relatively young medical specialty, consequences of insufficient sleep do not readily come to our attention. Insufficient sleep, no matter whether caused by a sleep disorder or sleep deprivation can have catastrophic consequences. You may remember the grounding of the tank ship Exxon Valdez. The main factor for this event was that the captain had transferred command to the third mate. And he was severely sleep deprived.
Sleep deprivation = Accident risk
Sleep loss is also referred to as sleep debt. The most important fact to know about sleep loss ist that it is cumulative. That means that if we only lose one hour of sleep every night, at the end of the week we have acquired a cumulative sleep debt of 7 hours. This roughly corresponds to one full night of sleep loss. Every sleep debt will cause the daytime symptom of sleepiness. And sleepiness leads to an impairment of reaction time. This for example can cause a driving accident or in the case of the Exxon Valdez a catastrophic event. A sleep debt can only be repaid by sleep.
The cause of daytime sleepiness
Daytime sleepiness can also result from having a sleep disorder. Many sleep disorders alter the normal structure of sleep so that it cannot counteract the physiologic period of sleep debt, i.e. the 2/3 of the day that we spend being awake. Sleep disorders can effect all ages and thus be found in children, adolescents, adults, and seniors.
The most common behavioral causes of daytime sleepiness
- Jet Lag
- Sleep debt (acute or cumulative)
- Substance abuse (alcohol, nicotine, drugs)
The most common sleep disorders causing daytime sleepiness
- Sleep apnea
- Periodic movements during sleep
- Restless Legs Syndrom and PLMD