Reader Comments

Sleep Wave

by Alisa Princy (2020-01-02)

The Harvard Business Sleep Wave Review review found that a week of sleeping 4 or 5 hours a night induces performance impairment equivalent to a blood alcohol level of 0.1% (the UK drink driving limit is 0.08%). So whilst we applaud those who work long hours we would be less impressed if we saw our colleagues tucking in to a couple of pints of beer before work every day. The problem is that fatigued people do not believe their performance is impaired even though objective scores show it is. In respect of obesity are if we are tired we crave high-carbohydrate, sugary and fatty foods to give us a boost. We may also crave caffeine, which can turn into a vicious downward spiral as caffeine impact our ability to sleep at night - the half life of a cup of coffee can last up to 6 hours. By not getting enough sleep we don't produce sufficient growth hormone to counter cortisol (associated with stress) which is also responsible for release of sugar into the blood stream. Excess sugar is then converted to fat and is stored around our waists. Research conducted by Warwick and UCL (as presented last year) studied 10,308 Civil Servants between 1985 and 1988 and again in 1992. They found that the risk of dying of fatal heart disease doubles among people who cut the hours of sleep from 7 to 5 hours. There has been some considerable research around fatigue and safety in industrial settings, particularly where shift work is involved (see Loughborough Sleep Research Centre and Surrey Sleep Research Centre here in the UK). We also understand that fatigue leads to a great many car accidents every year. Fatigue was highlighted as key reasons for other major disasters such as the Exxon Valdez, Three Mile Island, Chernobyl, Challenger Space Shuttle and the Selby rail crash. What other research has there been showing that fatigue impacts performance? Studies at the University of Pennsylvania split 48 adults into 3 groups, each of which slept for either 4, 6 or 8 hours a night. Tasks were then undertaken to test motor skills and memory. By the 14th day the 4-hour sleepers were 14x more likely to make errors and the 6-hour sleepers 11x more likely to make errors than the 8-hour group.