Sleep drive is the homeostatic regulatory process which balances our need for sleep. It is also referred to as sleep pressure or sleep load. In effect it means, the longer we stay awake the greater our desire for sleep as the ‘pressure’ builds up whilst we are awake then reduces whilst we asleep until it lowers to a point which causes us to wake up. We can think of sleep drive as an appetite for sleep. The stronger your appetite then the easier it is to sleep.
- High sleep drive (high sleep pressure) = sleepy
- Low sleep drive (low sleep pressure) = alert
The homeostatic sleep drive (pressure) and circadian rhythm (wakefulness) are synchronised as illustrated above. Both wakefulness and sleep drive increase during day time with wakefulness overriding the drive for sleep. Sleep onset occurs when sleep pressure drive is high and wakefulness is dropping, due to external cues stimulating the hormone melatonin production. Morning awakening occurs sometime after wakefulness begins to rise and sleep pressure drive is low. Times are for example only.
It is easier to fall asleep when sleep drive is high due to this build up of sleep pressure.

Sleep Drive can be affected by:
- Long afternoon naps, which lowers sleep drive, then falling asleep at ‘normal’ bedtime will be harder.
- Not keeping a regular sleep schedule.
- Falling asleep in front of the TV and then waking later to go to bed.
- Going to bed when not feeling sleepy.
- Not getting up in the morning (sleeping in late)
Sleep Restriction
Intentionally staying up longer (sleep restriction) can help to increase our sleep drive thereby helping to fall asleep quicker and staying asleep throughout the night.
It’s important to note, if you have a client who has trouble feeling sleepy at bedtime due to a low sleep drive then introducing the concept of sleep restriction can be something to explore BUT please don’t let the client stay awake for hours on end to increase sleep drive! Typically staying awake for an extra 30 minutes is suggested and not going below 5.5 hours of sleep a night. Also this is a short term strategy of say a week or two of going to bed 30 minutes later until sleepiness builds up then adjust bedtime back to get the quantity of sleep needed.