MANY of us have very demanding jobs that have us working late into the night and arising early in the mornings to beat the traffic for work or to take children to school. Others arise early in the mornings for exercise and then preparation for work.

All the above ensures that our body is not getting the minimum seven hours of sleep it needs each night, to keep healthy and reduce the risk of premature death (mortality).

While sleep requirements vary slightly from person to person, most healthy adults need between seven to nine hours sleep each night to function at their best. Children and teenagers require even more.

Our sleep requirements tend to decrease with age, however, most older individuals still need at least seven hours of sleep for maximum efficiency. The minimum amount of sleep that older people should get is six hours each night.

Sleep deprivation

Sleep experts say that if you feel drowsy during the day, it is a sure sign that you did not have enough sleep the night before. Further, the amount of sleep a person needs will increase if he or she has been deprived of sleep in previous days.

Getting too little sleep creates a ‘sleep debt’, which is much like having an overdraft at the bank. Eventually, your body will demand that the debt be repaid.

A little known fact is that sleep deprivation will kill you more quickly than would food deprivation. Normal falling asleep at nights should take around 10 to 15 minutes. If you fall asleep in less than five minutes, it is likely that you are sleep deprived.

When we are sleep deprived, our judgement, reaction time and other body functions are impaired.

People have memory problems, they feel depressed, their immune system is depressed, thereby increasing their chances of becoming sick, and their threshold for pain is lowered.

In fact, individuals who were tested by using a driving simulator or by performing an hand-eye coordination task did as badly as or worse than people who were intoxicated. Sleep deprivation magnifies the effects of alcohol on the body, and so a fatigued person who drinks alcohol becomes much more impaired than an alcoholic who is well rested.

Fatigue and accidents

While not measured or evaluated in this country, driver fatigue was responsible for an estimated 83,000 motor vehicle accidents during the period 2005-2009 in the USA, according to the statistics of their National Highway Traffic Safety Administration. However, some researchers believe the numbers are actually much higher.

Since drowsiness is the brain’s last step before falling asleep, driving while drowsy often leads to disaster. Further, caffeine and other stimulants cannot overcome the effects of severe sleep deprivation.

The guidelines of the USA National Sleep Foundation state that you are probably too drowsy to drive if you have any of these signs:

a) Have trouble keeping your eyes focused;

b) Can’t stop yawning;

c) Can’t remember driving the last few miles;

c) Have trouble holding your head up;

d) Daydreaming or having wandering thoughts; or

e) Drifting in and out of lanes.

Dysania

Dysania is the term used for the state of finding it very difficult to get out of bed in the mornings.

Some people find it difficult to get out of bed every now and then, but those suffering from dysania find it particularly difficult every day and is most likely a form of chronic fatigue syndrome.

Getting adequate sleep is essential, and it has been found that humans are the only mammals that willingly delay sleep, much to our detriment.

The benefits of sleep include improvements in the functioning of growth and stress hormones, our immune system, our appetite, our breathing, our blood pressure, and our cardiovascular health.

On the other hand, inadequate sleep increases our risk for obesity, heart disease and infections.

Multiple studies have found that short sleep duration is associated with a higher mortality risk.

So how might you reduce that risk by getting sufficient sleep each week? Can a very hectic workweek that causes too little sleep be counteracted by sleeping for some extra hours on Saturdays?

A solution

Recent research into this possibility has provided “yes” as the answer. A cohort study of more than 40,000 adults under the age of 65 years found that, compared to those who slept seven hours daily on the weekend, those who slept an average of only five hours or less each night over the weekend had an increased mortality risk (risk of death) of 52 per cent.

Interestingly, the mortality rate among the adults who had shorter sleep hours during weekdays but longer sleep hours on weekends did not differ significantly from those who were averaged seven hours of sleep per night consistently.

So, the take-home message is that catching up on sleep over the weekend can be a sound health practice for all groups of people.

Dr Derrick Aarons MD, PhD, is a consultant bioethicist and family physician; a specialist in ethical issues in health care, research, and the life sciences; the health registrar and head of the health secretariat for the Turks & Caicos Islands, and a member of UNESCO’s International Bioethics Committee (IBC).