Exercise and sleep

STUDY:STRENGTH TRAINING

AND AEROBIC EXERCISE CAN IMPROVE SLEEP

An American study looked at how different types of exercise can affect sleep patterns, even for people living with diabetes, writes MARIAN BRENNAN

Getting more sleep isn’t usually the first thing people think about when they start an exercise regime. But we’re increasingly coming to understand that improving our level of fitness has wide-reaching health benefits. Sleeping well is closely linked to health and well-being, with poor sleep being associated with an increased risk of overall mortality and a range of long-term health conditions, including diabetes. As you may have seen in our special Sleep issue (Diabetes Matters, Spring 2021), getting a good night’s sleep is proving harder and harder. Around a third of Americans report getting too little sleep or insomnia (which is defined as waking more than three times a night). Changing how you exercise is one of the simplest and easiest ways to improve your sleep. Traditionally, studies have focused on what is called moderate-to-vigorous aerobic activity (MVPA), which might include running, cycling or walking. A recent study from American journal Sleep Health turned its attention to emerging evidence that musclestrength training (MSE) may have additional benefits. An earlier review of that evidence from 2018 showed that, when compared to no exercise, undertaking MSE led to significant improvements in sleep quality and a range of other benefits. The new study set out to examine what benefits there might be for people who combine moderate-to-vigorous activity with strength training. While it was already known that doing so reduces your risk of dying from cancer and improves your cardiac and mental health, there was little known about specific benefits for sleep.

For the sake of the study, sleep health was measured as having five components – short sleep, long sleep, poor quality sleep, observed snoring and observed breathing stoppage. The study looked at 47,564 adults and found that, for those aged 18-64, sleep health – with the exception of short sleep – was noticeably better for those who were following a MVPA and MSE program. For those aged above 65, the news was even better – the risk for all five components was significantly reduced. This improvement was measurable even for those living with long-term conditions such as hypertension, depression or diabetes. The defined list of aerobic exercise included jogging, walking, tennis and soccer – but not milder activity such as bowling, golf, gardening or house maintenance. Muscle strengthening activities included using your own body weight like yoga, sit-ups or push-ups and using weight machines, free weights or elastic bands. Participants were asked to self-report poor sleep (“Over the past two weeks, on how many days have you had trouble falling asleep or staying asleep or sleeping too much?”) and whether anyone had told them they either snored loudly or stopped breathing during their sleep.

Sleep health – with the exception of short sleep – was noticeably better for those who combined aerobic exercise with strength training.

This new study is seen as being important because it is the first to demonstrate a measurable improvement in sleep health for people who combine an aerobic exercise and strength training program. The authors say their data consistently showed a favourable association between a mixed program and the components of sleep measured above. At this stage, it’s unclear exactly why this mixed program does improve sleep. Clinical studies have shown, however, that combining MSE and aerobic MVPA does have positive effects on cardiometabolic bio-markers and indicators of mental health. Both forms are also known to improve depression and anxiety symptoms, which are also associated with sleep. One possible explanation for the improvements, of course, is that working out more – and in two different styles – uses up more energy. Basically, when you wear your body out through a combination of different activities, you feel more ready for sleep.