Why is sleep important and how much sleep do you need?

by Dr. Silberstein

Sleep is such a fundamental part of life – we spend about a third of our life sleeping. But why do we sleep, and is sleep necessary?
 
Try this – ask a friend why she goes to sleep every night, and she might say “because I’m tired” or “it’s bedtime.” Now try asking her what is the purpose of sleep, and your friend will most likely not have an answer. However, if you ask your friend (or yourself) how she feels when she can’t get a good night’s sleep, she’d likely say she feels lousy in the morning. Indeed, sleep loss (due to occasional stress, jet lag, or a fun night out with friends) often results in difficulty concentrating, slower reaction time, frustration and irritability, and difficulty doing one’s job properly. 
 
While science has not fully answered the question “why do we sleep exactly?” we do know sleep is essential to our physical and mental health and well-being. It is believed that sleep plays important roles in maintaining the body and mind (for example, the repairmen of damaged bodily tissues). Sleep conserves energy, improves immunity, and regulates body temperature. In addition, sleep deprivation studies have shown that different sleep stages (or “types” of sleep) serve different functions and purposes. For example, some sleep stages are involved with the restoration of physical energy and help us feel refreshed in the morning, while other stages are involved with storing and retaining new memories.
 
 People often wonder if they are getting enough sleep. The amount of sleep a person needs varies widely by age and from one person to the next. Some people do fine with just 4-5 hours of sleep a night, while others need 10 hours to feel and function their best. In general, though, the average adult needs 7-9 hours of sleep per night.
 
If you feel refreshed and alert in the morning, you’re probably getting enough sleep. If, however, you experience any of the following, your sleep may be insufficient in quality and/or quantity*:

• Not feeling refreshed in the morning
• Feeling like you didn’t get any/enough sleep
• Dozing off when you need to stay awake, such as during a work meeting or while driving.
• Falling asleep when you want to stay up, such as when watching TV

 
To summarize, even if we don’t fully understand the processes involved with sleep, we do know that good, sufficient sleep is necessary for one’s physical and mental health, for optimal cognitive functioning, for learning, as well as many other essential functions.
 
*This list is non-comprehensive and is not intended for diagnostic purposes; if you suspect having a sleep disorder, you should consult a health-care provider.