The average person spends around a third of their life asleep. In this time, our bodies are able to replenish energy stores and make repairs, while our minds organise and store the memories of the day before. The amount of sleep you need depends on your age, sex, health and other elements, and sleep cycles change as we grow older.
However, here is a general guide.
Remember though that there is no magic number for how much sleep you should get, it is whatever is natural for you. We all feel tired at times but it is important that it is not disruptive to your daily life and general health. It’s important not to get too hung up on your sleep quantity but focus on sleep quality instead.
The Sleep Cycle
When we first fall asleep we enter non-rapid eye movement sleep (NREM). This is divided into three stages, with each becoming progressively deeper. NREM1 and NREM2 are light phases of sleep, from which we can be easily roused. NREM3 becomes deeper, and if woken up, we can feel disorientated. Following on from this is rapid eye movement sleep (REM), the stage at which we dream.
Each sleep cycle lasts around 1 and a half hours, and in order to feel fully rested and refreshed when we wake up, we must experience all four stages. A full night’s sleep will include of five or six cycles, while a disturbed, restless night consists of fewer.
Ideally, our circadian rhythm will climb in the morning and make us feel alert and refreshed. It then peaks in the evening, and after being awake for around 15 hours, we will feel the pressure to sleep again. As the night draws in, our circadian rhythm drops to its lowest level, and we are able to close our eyes and fall asleep.