Sleep Cycles: The Natural Way to Sleep
Modern sleep advice recommends we sleep in cycles rather than hours, as this is the natural way our bodies are designed to sleep in. Using sleep cycles could help get the right amount of sleep you need to function properly throughout the day, without feeling tired.
Our sleep expert, Dave Gibson, defines a sleep cycle and his tips to help you make sure you get enough sleep.
A sleep cycle lasts for 90 minutes; beginning with two stages of light sleep, then two stages of deep, physically restorative sleep and finally Rapid Eye Movement (REM) sleep, which is when we dream and restore our mental faculties. At the end of each cycle, we naturally enter a period of light sleep, often waking up without knowing it before going into another cycle. If you wake up in a middle of a cycle, especially from a stage of deep sleep, you can feel groggy, which we often put down to a lack of sleep.
We get relatively deeper non-REM sleep in the first third of the night and relatively more REM sleep in the last third of the night before daybreak. This shift from deep sleep to REM sleep happens at certain times of the night, irrespective of when you go to sleep. We need the correct ratio of both to feel refreshed when we awake in the morning. Therefore, if you go to sleep very late, you can often end up feeling foggy-headed the next day.
Here is how to use sleep cycles to make sure you get the right amount of sleep:
1. Aim to go bed when you first feel tired
Prehistorically, we would have felt sleepy and gone to bed sometime between dusk and dark, i.e. 8pm to 12pm. This is regarded as the optimal time to sleep to get the correct balance of REM and non-REM sleep.
2. Consider your hereditary sleep habit
We inherit our sleep genes, ‘chronotypes’, from our parents. These naturally determine when we want to sleep and whether we feel more alert in the day or prefer to be active in the night. You should work with these traits, as they can shift when you wake in your sleep cycle by as much as an hour.
3. Try to be consistent
As daylight hours only change by 2 minutes a day, our natural body clock is generally stable. Aim to have a regular sleep routine. Relax and unwind before getting into bed , be consistent with the time you go to sleep, as this will help you get to sleep more easily.
4. Aim to sleep in cycles
If you want to feel alert in the morning, it can be better to aim to sleep in cycles. For example, instead of aiming for 8 hours of sleep, try for 7.5 hours, as this equates to 5 full cycles. Similarly, 9 hours (6 cycles) is a natural break. If you are up late and know you are going to get less sleep than normal, it can better to aim for 6 hours of sleep (4 cycles), as it could help you feel more alert in the morning. You can then make up the sleep debt the following night or with a nap during the day.
5. Adjust your sleep time until you can wake without an alarm
Use this sleep cycle formula to work out the best time to get to sleep based on the time you need to wake up. For instance, if you need to get up at 6:30am, count 5 sleep cycles (7.5 hours) backwards, this means you would need to be asleep by 11pm. Try to go to bed before this time to give you time to nod off. Keep tweaking your bedtime until you can wake up naturally without an alarm, this means you are getting enough for your sleep.