What is the one thing we spend more of our lives doing than any other single thing? It is something that we do every day and we largely take for granted.
The answer, is of course, sleep.
In the hierarchy of the body’s needs, sleep is number three after air and water. The body can go much longer without food than it can go without sleep. Whilst it is very rare for people not to eat when they are hungry, it is fairly common for people to not go to bed when they are tired.
Over the course of the twentieth century the average number of hours slept per night fell from over nine to under eight. One of the main reasons people tend to sleep less is actually because they can. The advent of electricity has meant that we can stay in well-lit environments 24 hours per day. Today there is much to keep us entertained after dark whereas, a century ago, there were not too many options after dark other than to go to sleep.
One of the commonest complaints I hear as a doctor, is tiredness and the commonest reason for this, is lack of sleep. A person, who needs eight hours sleep a night and gets seven, will by the end of one week, be a whole nights sleep in arrears. This continues to accumulate over time but it won’t be until, perhaps months down the track that symptoms begin. The body is remarkable at compensating for the less than ideal ways in which we sometimes treat it.
Sleep patterns are also influenced by societal attitudes. We tend to judge our success by our busyness and number of things we have to do. With this mindset, sleep is seen as expendable. Sleep time is “cribbed “ from, to do other things, which are seen as more important.
Various studies have shown the importance of sleep. At UCLA, it was demonstrated that there was an increase in silent inflammation of the body in people who did not get an adequate amount of sleep. Slow or silent inflammation is a critical component in the development of heart disease, stroke and various autoimmune conditions. A Japanese study showed lack of sleep as a separate risk factor for heart disease.
People who get adequate sleep tend to eat less junk food and it has also been shown that lack of sleep correlates with higher rates of obesity. On top of this inadequate sleep impacts on our immune system making us more susceptible to viruses.
Our children need sleep too. Teenagers who do not want to get out of bed may not be as lazy as we like to portray them as. It is likely they do need the sleep. Most interestingly was an American study which showed that when a county in Kentucky decided to push back the start of middle and high school by an hour, traffic crash rates for drivers aged 17 to 19 dropped 16.5% and of course, the students reported getting more sleep.
For adults NASA tests have shown that after 20 hours continuously awake, an adult’s reaction time is comparable to a blood alcohol reading of 0.05, which is the cut off for drink driving in most countries.
The case is clear. You would not dream of deliberately not breathing enough air or not drinking if thirsty. Sleep needs to be seen in the same light. Sleep is not something to relegate to the “I will do it after everything else is done pile”. It is a pillar of health and needs to be treated with respect. In simplest terms this means you need to set aside the eight hours that your body needs for sleep – for sleep and not anything else.