We spend approximately one third of our lives doing it. It is unsurprising therefore that sleep is one of the most valuable and underrated tools we have to help us improve our health and wellbeing.
Why do we sleep?
This is a question which has baffled scientist for years. Though the exact reason is not known, it is widely accepted that sleep is necessary for the maintenance of cognitive functions such as memory, speech, creative and flexible thinking.
It is less likely that sleep is needed for the body to recuperate from our daily activities, as the amount of energy saved by sleeping for eight hours is approximately 50kcal, the same amount of energy in half a slice of bread.
A good way to understand the role of sleep is to examine the effects of sleep deprivation. A lack of sleep has serious effects on our brain’s ability to function. Many of us may be well acquainted with the results of pulling an all-nighter: grumpiness, grogginess, irritability and forgetfulness.
After just one night without sleep, concentration becomes more difficult and attention span shortens considerably. Interestingly , 17 hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol level of 0.05% (two glasses of wine)! This is the legal drink driving limit in the UK!
In 1910 the average time people slept for was about nine hours. Over the last century it has fallen to between six and seven hours. Many factors have influenced this such as: heat and light in homes, various forms of entertainment available throughout the night, busy lifestyles, long working hours and long commuting times. Many city workers will be out of the house for 12 hours or more a day, if they sleep for eight or nine hours, it leaves them very little time to do anything else during the working week.
So why does it matter?
Sleep deprivation not only has a detrimental effect on cognitive functioning, but also on emotional and physical health. Research also suggests that a lack of sleep may increase the risk of obesity, as hormones that play a key role in controlling appetite and weight gain are released during sleep. Your ability to metabolise glucose deteriorates by up to 40% and the associated rises in cortisol (stress hormone) makes weight gain through fat storage more likely.
Sleep deprivation also leads to increases in sympathetic nervous system activity (similar to a “fight or flight” response),which can lead to rises in blood pressure and damage to the heart and kidneys. It is unsurprising then that disorders such as sleep apnoea, which result in excessive daytime sleepiness, have been linked to increased stress and high blood pressure.
Quality of sleep is also crucial. Our bodies have biorhythms, which tell us when to wake and when to sleep. The natural pattern would be to sleep for two or three hours after lunch and again for five or six hours at night. This is why concentration is poor immediately after lunch and improves by the mid-afternoon. It is also the reason that more accidents happen both on the roads and at work at this time of day.
The most important point in the day for setting our body clock, is the time that we get up in the morning. If you want to catch up on sleep, the worst thing that you can do is to have a “lie-in” for more than one or two hours. This is simply because you are shifting your waking time and biorhythms.
[stextbox id=”warning” shadow=”true” color=”ff0000″]WW TIP #1: If you need extra sleep, you should try to go to bed earlier for a few evenings and if you do decide to sleep in late at the weekend, it should only be for one or two hours.[/stextbox]
Sleep hygiene refers to a variety of different practices that are necessary to have adequate, quality nighttime sleep and full daytime alertness. Many of these points will seem like common sense, but it is surprising how many of these important measures are ignored by many of us.
- # Avoid prolonged napping during the day as it can disturb the normal pattern of sleep and wakefulness.
- # Avoid stimulants such as caffeine, nicotine, and alcohol too close to bedtime.
- # Alcohol causes initial drowsiness, but as the body metabolises it and levels start to drop a rebound stimulant effect can occur in the early hours. Both alcohol and prescription sedatives (like Valium) can affect normal sleep architecture. These substances can shorten the amount of time spent in deep sleep, which is essential for feeling rested.
- # Exercise can promote good sleep. Vigorous exercise should be taken in the morning or late afternoon. A relaxing exercise, like yoga, can be done before bed to help initiate a restful night’s sleep. Body temperature gradually decreases at night and this drop signals the initiation of sleep. Vigorous exercise at night can elevate core body temperature, which can have a negative affect on the ability to fall asleep.
[stextbox id=”warning” color=”ff0000″]WW TIP #2: A cold shower immediately after strenuous exercise taken at night can help lower core body temperature, making it easier to fall asleep.[/stextbox]
- # Food can be disruptive right before sleep; stay away from large meals close to bedtime. Also dietary changes can cause sleep problems, if someone is struggling with a sleep problem, it’s not a good time to start experimenting with spicy dishes. Remember, chocolate contains a caffeine-like stimulant called theobromine.
- # Establish a regular relaxing bedtime routine. Try to avoid emotionally upsetting conversations and activities before trying to go to sleep. Don’t dwell on, or bring your problems to bed.
- # Associate your bed with sleep. It’s not a good idea to use your bed to watch TV, listen to the radio, or read. Blue light emitted from consumer electronics such as laptops, deceive our minds that it is still daytime, preventing the secretion of melatonin, an important hormone in the initiation of sleep.
- # Make sure that the sleep environment is pleasant and relaxing. The bed should be comfortable, the room should not be too hot or cold, or too bright.
It is essential to acknowledge the need for adequate sleep and to recognise the difference that it can make to your performance. An extra couple of hours a night can improve your mental abilities the following day, allowing you to function more effectively.