The amount of sleep that an individual requires each night is dependent on many factors such as age, gender, lifestyle factors such as stress, and your daily schedule. Genetics plays a role in both the amount of sleep a person needs, as well as his or her preference for waking up early (morning people) or staying up late (night owls). Our internal biological clock, which regulates the cycling of many functions including the sleep/wake cycle, can vary slightly from individual to individual. Although our internal clock is set to approximately 24 hours, if your clock runs faster than 24 hours, you tend to be a “morning person”; if your clock runs more slowly, you tend to be a “night owl”.
As a general guide, the amount of sleep certain age groups require is highlighted by the Sleep Spectrum below:
When we don’t get enough sleep, we accumulate Sleep Debt or sleep deprivation. The only way to “pay off” our sleep debt is to make it up by sleeping extra hours. Let’s consider the potential impact of a 2 hour disruption in the sleep cycle of a student who normally sleeps between 12-midnight until 8:00AM. If the student does to sleep at 2AM and still wakes up at 8AM, they are sleep deprived. To compensate for that loss, they may need as much as 4 hours of extra sleep the next day.
It’s like borrowing from a bank because the only way to get out debt is to pay it back.
An objective measure of a person’s sleep debt would be by the amount of time it takes for a wide awake person to fall asleep. A sleep deprived person will fall asleep within a minute, indicating a higher sleep debt.
An easier way to measure one’s sleep debt is simply observing whether one becomes sleepy during the day. This is largely caused by a substantial sleep debt.
A large sleep debt is associated with lower levels of…
- Alertness and ability to maintain focus and attention
- Cognitive performance: learning, memory, and creativity
- Energy & motivation
- Control, coordination, and impulsiveness
- Resistance to infections
You know you need more sleep when…
- It takes you at least an hour to fall asleep every night of the week
- You can’t get out of bed when the alarm sounds
- You worry about getting enough sleep most nights of the week
- When you wake up in the night, you can’t get back to sleep
- You use sleeping pills or alcohol to help you sleep
- You feel exhausted from lack of sleep
- You sleep in or take daytime naps to make up for lack of sleep
- You get drowsy during the day, or need caffeine to stay alert
Sleep & Academics
Several recent studies have clearly demonstrated that the loss of REM sleep creates a dramatic reduction in the retention of recently learned information. If the sleep cycle is reduced by even two hours, much of what was read or studied earlier that night may be lost. Consequently, learning efficiency is also reduced and grades may be negatively affected. Looking for explanations for academic difficulties or poor grades could be as simple as examining one’s sleep hygiene.
- You consistently do not get enough sleep, or the sleep you do get is not restful
- You struggle to stay awake while driving
- You have trouble staying awake when doing something passive, such as studying
- You have problems concentrating at work or at school
- Friends, or family members, tell you that you are often sleepy
- You begin to respond to things slowly
- You have trouble remembering things or have difficulty in controlling your emotions
- You feel the need to nap several times a day
To examine how much sleep debt you have, take the SLEEPINESS QUIZ
How Many Hours of Sleep Do I Need Each Night?
Although there is a recommendation that students get around 9 hours of uninterrupted sleep per night, individual needs may vary. There are a number of different activities that you can try to find out YOUR sleep needs.
Take a Sleep Vacation
During a two-week period, when you have a flexible schedule or perhaps are on vacation, pick a consistent bedtime and do not use an alarm clock to wake up. Chances are that for the first few days or week you will sleep longer because you’ll be paying off your “sleep debt” – the amount of sleep deprivation that you’ve accumulated over a period of time. If you continue going to bed at the same time and allowing your body to wake up naturally, you will eventually establish a pattern of sleeping, essentially the same amount of time each night, identifying your individual sleep need.