Did you know that a complete night’s sleep includes five or six sleep cycles? The Sleep Council says that each cycle lasts up to 1.5 hours and consists of three stages of non-rapid eye movement sleep and one stage of REM sleep when we dream. To feel completely rested, we need to have had all four stages in all sleep cycles.
A study conducted in 2018 by the Onassis cardiac surgery centre in Athens found that six to eight hours sleep is the amount adults need for a healthy heart. People sleeping less or more than that number are said to be at a higher risk of coronary artery disease or a stroke.
Healthline.com reveals that a lack of sleep can also cause impaired focus and decision making, as well as a high risk of obesity, diabetes and Alzheimer’s. Sleep deprivation can affect how we regulate our emotions, immune system, metabolism and internal body clock. On the up side, getting the correct amount of sleep, helps our bodies to restock our energy supply and lets our brains process the day’s activities.
The amount of sleep we need as adults doesn’t vary hugely as an adult, but there is a slight difference when you hit 65. According to The Sleep Council, the 18-65 group needs between seven and nine hours a night, whereas those over 65 only need seven to eight. But why is this? Surely we should sleep for longer with more time on our hands?
A 2016 study in Russia by Arcady Putilov found that older people were tired at different times of the day to younger people. Putilov thinks this may be because the slow-wave activity timings in our brains change as we age, and circadian rhythms and the release of melatonin weaken.
If you struggle getting off to sleep or staying asleep, you might need to change your daily routine or environment. It’s best to stick to a set sleep schedule, even at the weekends, to regulate your body clock. Daily exercise is known for aiding restful sleep, as is avoiding caffeine. Get yourself into the habit of relaxing before bed, perhaps with a bath, a warm milky drink or by reading a book. Banish electronic devices from the bedroom and ensure your room is a quiet and neither too warm or cold.
By age, how much sleep we need, on average, a night…
Age 1–2 years old: 14–15 hours a night
Age 1-3 years old: 12-14 hours a night
Age 3-6 years old: 10-12 hours a night
Age 7-12 years old: 10-11 hours a night
Age 13-17 years old: 8-9 hours a night
Age 18-65 years old: 7-9 hours a night
Age 65+ years: 7-8 hours a night