While much focus has been placed on attaining optimum levels of performance through better exercise routines, nutrition and recovery techniques, it is only recently that attention has turned to the role sleep has to play.
Research at Stanford University found that achieving nine hours of effective sleep improved basketball players’ performance by as much as 10%. This figure is attributed to both the physiological and psychological effects of sleep – with the mental repair work carried out during sleep deemed to be every bit as important as the increased energy levels and ability to train harder one would associate with improved performance.
The brain’s ability to coordinate the body’s actions and movements are influenced by the different phases of sleep we all experience. It has been found, for instance, that high levels of physical activity causes the production of new brain cells, which become functional within days.
Sleep deprivation affecting the metabolism
Further studies in the US at the Chicago Medical School showed that students deprived of sleep metabolized glucose less efficiently over time, while levels of cortisol were higher. These cortisol readings can be linked to memory impairment, age-related insulin resistance and slower physical recovery from exercise.
These findings support the growing body of research that linking sleep deprivation with weight problems and even obesity in wider society.
“We have done a series of studies looking at weight and sleep, and studying the metabolic rate,” says Dr Shahrad Taheri, Consultant Endocrinologist at Birmingham Heartlands Hospital. “We discovered that people who sleep for significantly less than seven hours a night often end up being obese.”
It also seems that people who sleep for fewer than four hours a night are 73% more likely to gain excess weight, as the body’s reaction is to crave up to an extra 900 calories a day.
During a typical night’s sleep, the average person loses around 1 litre of water through breathing and perspiration. But overheating at night can more than double this figure.
Dr Daniel McNally, director of the Sleep Disorders Center at the University of Connecticut Health Center says:
“Your body temperature tracks your circadian rhythm, so as night begins, your body temp falls and it reaches a minimum right after you go to bed. If you are in an environment where you can’t lose body heat, for instance if it’s hot and humid, you won’t sleep well.”
The consequences for professional athletes are even more significant. The effects of dehydration on performance and recovery are well documented, and by failing to take into account the sleeping environment, sports men and women can drastically reduce their ability to perform at their best.
Hidden sleep deficit
The problem with sleep deprivation is that sufferers often don’t know they are building up a sleep deficit. The human brain is remarkably adept at reacting to the strains put on it, and for most of us a gradual reduction in sleep is something we learn to come to terms with. A slow increase in fatigue or irritability and a gradual drop in concentration, energy or memory span can all begin to seem the norm – that is, until an improvement in sleep pattern reveals how much poorer our performance had been.
Director at Northumbria University’s Centre for Sleep Research, Professor Jason Ellis, says: “The number of people suffering from sleep problems is significant. An estimated 50% of the UK population have some problem sleeping.”
It is important, too, to draw the distinction between hours lying in bed and hours of quality sleep. Nine hours lying on an uncomfortable mattress in a warm room with a TV or computer playing can be significantly less productive than a shorter period of time spent enjoying high quality sleep.
Professor Ellis has worked closely with Mammoth Technologies in the development of their mattresses. At Northumbria’s Sleep Laboratory – the largest of its kind in Europe – Professor Ellis and his team have performed clinical trials into “Sleep Efficiency”, “Sleep Enjoyment” and “Sleep Onset Latency” (how quickly people fall asleep), analysing brainwaves during the different phases of sleep and assessing the factors that can positive and negative impacts on sleep.
During tests involving several mattress brands, participants were found to be more likely to get to sleep quicker and experience fewer awakenings over the course of a night on a Mammoth than on a competitor mattress – an increase in efficiency of 7%. Participants also rated their sleep as 20% more enjoyable over the course of the trial.