3 May, 2021
As I’ve discussed in previous articles, including Sleep and food – what’s the connection? and Get a good night’s sleep – at last!, Australia has a sleep problem.
Somewhere between 13 and 33% of the Australian population suffers from regular insomnia (difficulty in either getting to sleep or sleeping through the night), and many more experience intermittent bouts of insomnia due to disruptions to daily routines, or periods of stress. Furthermore, insomnia worsens as we age, especially for women.
Amongst the 10 tips for a better night’s sleep that I share in Get a good night’s sleep – at last!, is the recommendation to engage in regular physical activity.
All you sleep-deprived people are probably groaning right now, “But I’m too tired to exercise!” Yep, I hear you. It’s hard to motivate yourself to get up early for a walk, or hit the gym on your way home from work, when you can’t remember the last time you had a decent night’s sleep and woke up feeling refreshed.
And some of you might be retorting, “I tried exercising, but it didn’t help me sleep any better.” I hear you too. A study published recently by a team of researchers from the University of Tsukuba in Japan, validates your experience, but also suggests that you should persist with exercise anyway.
Why? Because exercise improves the quality of your sleep, whether or not you notice it.
The study, ‘Exercise improves the quality of slow-wave sleep by increasing slow-wave stability‘, measured the sleep quality of young men who were healthy but relatively inactive, using not just standard polysomnography (sleep study) techniques, but a novel computational method for analysing brain signals, called coefficient of variation of the envelope (CVE).
The study used a randomised crossover design, meaning that each participant served as his own control. Participants attended the sleep laboratory on two separate occasions, which were spaced one week apart, to have their overnight sleep studies performed. On one of those occasions, they performed an hour of vigorous exercise (running on a treadmill at 60% V˙O2max, for the nerds), beginning 6 hours before bedtime.
While the participants did not report sleeping any better after exercising, the researchers measured several distinct differences in their polysomnography readings:
- Sleep latency was reduced, meaning participants fell asleep faster after exercise. This is a godsend for people who suffer onset insomnia, the type of sleep disorder in which people find it hard to get off to sleep.
- Slow wave sleep (SWS) latency was reduced in the first sleep cycle, meaning that participants went into deep, restorative sleep faster, after exercise
- Rapid eye movement (REM) sleep latency was reduced, meaning participants completed their first period of restorative sleep faster, and moved into their first phase of intense dreaming sooner, indicating higher sleep efficiency.
- Coefficient of variation of the envelope (CVE levels) during SWS were lower, again indicating greater sleep efficiency.
To put it all in plain English, exercise allows your body to get more out of sleep in a shorter period of time. The physical demands of exercise are a hormetic stress – a beneficial type of stress, summed up by the maxim “what doesn’t kill you makes you stronger”, which causes your body to adapt in ways that improve its efficiency, and your health.
The researchers noted that one of the reasons the relatively unfit men who participated in this experience may not have noticed improved sleep quality after their exercise bout, was muscle soreness from unaccustomed exercise.
Insomniacs would be well advised to bear this in mind before rushing out to put these study findings to work in their own lives. Start slowly if you have been sedentary for a long time, and especially if you are chronically tired and/or recovering from illness.
A stroll around your neighbourhood or through a park, or a gentle yoga class, are ideal ways to ease back into physical activity. You can build up your exercise intensity, duration and frequency as your fitness level builds and the effects of exercise on your sleep quality start to pay dividends.
Putting aside the fancy-schmancy high-tech gadgetry that the Japanese team used to measure sleep quality in participants, the most important take-away of this new study is that exercise works when it comes to getting a better night’s sleep.
Now, how will you put this finding to work in your own life?
Leave A Response