Five things you should know about sleep
A study in the American Journal of Clinical Nutrition found that eating high-glycemic carb such as jasmine rice or cereal around lunchtime can halve the time it takes to fall asleep because these foods increase the amount of the sleep hormone tryptophan circulating in the blood.
The Sleep Council, a trade association, recommends a “sleep sandwich” of banana (rich in magnesium and potassium, which help relax muscles), Marmite (rich in B vitamins, which assist the release of tryptophan in the brain) and lettuce.
Failing that, try eating two kiwi fruits, which are rich in the relaxing hormone serotonin, an hour before bedtime; this has been found to help people fall asleep 35% faster after four weeks.
At Stanford University’s sleep disorders clinic, Dr Cheri Mah analysed the sleep/wake patterns of five female athletes over three weeks and asked them to perform a series of athletic tests that included sprinting, tennis serves and other drills.
On average, the women were getting between six to eight hours’ sleep a night, which, considering their activity levels, was probably too little. When the same subjects were asked to extend their sleeping hours to 10 per night, their performance in the drills improved significantly and they were able to run faster, hit tennis balls more accurately and exhibit greater arm strength.
However, Dr Neil Stanley, a sleep consultant who was formerly the director of sleep research at the University of Surrey, says you will know if you get enough. “Everyone has a different sleep requirement and some get by on six to seven hours, others need nine,” he says. “If you wake up tired every morning, then you probably aren’t getting enough. It’s that simple.”
READ: Professor John Brewer on the importance of sleep for athletes
Men who slept less than five hours a night for just one week were shown to have lower levels of testosterone than when fully rested.
In the University of Chicago study of fit 24-year-old males, it was found that sleep deprivation caused a 10-15% drop in testosterone, a hormone essential for building muscle mass and bone density.
Dr Jonathan Leeder, an exercise physiologist at the English Institute of Sport in Manchester, has researched the effects of sleep loss and says both strength and endurance “can take a knock” as a result.
During deeper sleep, human growth hormone (HGH) produced by the pituitary gland is released into the blood. It is HGH that enables essential recovery processes such as repairing muscles and converting fat to fuel.
Consequently, too little sleep means the body produces less HGH and more of the stress hormone cortisol that Leeder says “definitely won’t help with muscle recovery and building”.
Got a sleep tracker on your GPS watch? You could do worse than turn it off. Dr Kelly Glazer Baron, an associate professor at Rush University and a researcher on the sleep disorders programme in the department of behavioural sciences, has shown that an obsession with sleep data is causing more insomnia than it is curing.
“For some people, sleep tracking became an obsession which interfered with sleep rather than made it better,” Baron says of her paper in the Journal of Clinical Sleep Medicine. Stanley says the data produced by sleep trackers is “meaningless”.
If you do just one thing to aid your sleep, make sure you try to get up at the same time every day, Stanley advises. Hitting the snooze button for a weekend lie-in is not the answer.
Sleep researchers at the University of Arizona showed that a one-hour lie in at weekends was enough to cause ‘social jet lag’, a phenomenon caused by a discrepancy between your body’s internal clock and your sleep schedule, that she linked to mood swings and fatigue.
