I would argue that sleep is probably the most important thing for your health, particularly as you age. I’m a huge believer in exercise and diet for health and I regularly take supplements and have done for many years but the one thing that has the greatest effect on your over well being is sleep. Sleep is vital for human beings in so many ways. We are hard wired from an evolutionary perspective to sleep when it is dark. The onset of the light bulb, and more recently TV and the internet, mean we get less and less sleep than we have ever before throughout human history.
Many people get less than 6 hours sleep a night and often times the quality of that sleep is poor. It is commonly accepted by the medical profession that a healthy amount is 7-8 hours of restful sleep each night. However, it makes sense to get more sleep in the winter when the days are shorter and slightly less in the summer when the days are much longer.
Your sleep patterns are influenced by the hormone melatonin, which is released from the pineal gland in your brain. When light hits your eyes it effectively tells your pineal gland to stop producing melatonin which makes you sleepy. At the end of the day as light levels drop your melatonin levels begin to rise which will ultimately help you fall asleep.
There are two phases of sleep namely Rapid Eye Movement (REM) and non Rapid Eye Movement (NREM). NREM sleep makes up about 75% of our sleep and is split into four phases. You start off in Phase 1 which is a light sleep and move into Phase 2 where your breathing and heart rate begin to slow and you become disengaged with your surroundings. Phase 3 and 4 are your deepest and most restorative sleep where your body releases hormones such as Human Growth Hormone which is responsible for much of your cellular repair.
REM sleep, which makes up about a quarter of your nightly sleep, is characterised by darting eyes and dreaming and this is where your mental or emotional processing is believed to take place. Your periods of REM sleep get longer and deeper through the night.