“A well-spent day brings happy sleep”, (Leonardo da Vinci)
No. 10 – Sleep
Sometime around the summer of 2002 I was roped into participating in a study by Charlie Pedlar. For three days, we carted down to the sleep laboratories at Surrey University and spent about an hour having wires glued to my head, jaw, chin, arm, leg before going off to bed. I can tell you, polysomonography, pneumography, pulse oximetry, accelerometry and aural temperature measurement is not the best recipe for a comfortable night’s sleep. Nevertheless, after suitable familiarisation, Charlie was looking into the effect of hypoxia on our sleep patterns, and found that whilst brain wave patterns during sleep remained unaffected, overall sleep was disturbed through changes to respiratory activity such as sleep apnoea episodes.
The advance of smaller, more user friendly actigraph watches over the last 5 years or so, has meant that global sleep performance, assumed from the movement patterns shown overnight, can now be assessed with some growing degree of confidence. Sleep latency (difference between bedtime and sleep onset), sleep duration (speaks for itself), sleep efficiency (sleep duration expressed as a percentage of time asleep from bedtime to sleep end) and fragmentation index (measure of restlessness), all estimated from movement patterns can offer tangible insight into the effectiveness of sleep.
Presenting this data to a coach can not only open up a useful discussion and therefore education process about this crucial area but also demonstrate, intuitively, areas that can be improved. Simple strategies such as establishing an evening routine with a regular bedtime, (where similar activities to cue the anticipation of sleep), avoiding activities with a high cognitive demand (i.e. no computer games well into the small hours), avoiding caffeine in the second half of the day, are simple ways in which athletes have been helped to improve their sleep. As you can see from the terminology, there this is an interesting psycho-physiology interaction at play.
Actigraphy also unveils interesting trends if worn throughout the day, showing what athletes are upto in afternoon between sessions. A common example is shopping, mulling around malls for hours on end. For some (not me) this might well offer transcendental utopian recovery, for others this will create stress levels similar to front-line combat (me). The additional demand of afternoon activity, on top of training sessions or more pertinently a missed chance for good recovery time, can further have a knock on to the requirement for rest overnight.
Jonathan Leeder undertook a comprehensive comparison of the sleep patterns of a number of high performance athlete groups and controls. He saw that whilst sleep duration was not different between the groups, the athletes show inferior sleep quality. It is not clear why this is the case. One might think that athletes have got more to recover from and with their regular routines you might expect their sleep to be more structured and predictable and therefore a higher quality. This paradox still needs to be resolved or understood more clearly, since the prescription of physical activity to the general population is a treatment method used for insomnia.
Nevertheless, athlete sleep measurement has opened up dialogue, education and consequent behavioural change over the last few years into this untapped area of such dominant and potent recovery. In future years this topic might sit slightly higher in the top 10 list, as our insights develop further, but for due to the pertinence to recovery, an advance in technology, sleep support warrants inclusion at number 10, in the top 10 of applications of sports physiology.
For more on sleep see our extensive blog series by Luke Gupta and Kevin Morgan