Short bursts of light exercise in the evening – such as walking around the house in between TV programmes – may improve sleep length, a study has found.
Experts currently recommend that people avoid intense exercise before bed because it increases both body temperature and heart rate, which can lead to poor sleep.
But the effects of light activity have not been studied as widely.
Researchers set out to discover its impact, recruiting 30 people aged 18 to 40, who clocked up more than five hours of sedentary time during the day and two hours in the evening, to do exercises such as squats and calf raises for two to three minutes, every 30 minutes.
After these activity breaks, participants slept for an additional 27 minutes on average, compared with prolonged sitting.
Jennifer Gale, of the department of human nutrition at the University of Otago in Dunedin, New Zealand, told The National the results show the activity breaks do not need to be long or intense.
“The main thing is to get up and move your body – this could be marching on the spot, walking up down a set of stairs, or dancing around the living room,” she said.
“Performing some activity to interrupt prolonged sitting is better than doing none. This does not need to be long or very intense – the key is to frequently get out of your chair and move your body.”
Each participant wore an activity tracker and spent two four-hour sessions in a laboratory environment on the same day of the week, starting in the late afternoon, separated by a minimum period of six days.
In one session participants remained seated for four hours, while in the second they did three minutes of simple resistance exercise every 30 minutes over the four-hour period. Afterwards participants returned to their normal life.
Each activity break included three rounds of three exercises: chair squats, calf raises and standing knee raises with straight leg hip extensions for 20 seconds each.
Before the experiment, participants spent an average of 7 hours 47 minutes asleep, 10 hours 31 minutes sitting down, and 4 hours 55 minutes engaged in vigorous physical activity a day.
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Three out of four slept for the recommended 7 hours a night, while 21 per cent slept less than that, and 4 per cent slept longer than 9 hours.
After completing the activities, the average sleep duration was 7 hours 12 minutes, compared with 6 hours and 45 minutes after prolonged sitting.
And while the time at which participants attempted to go to sleep was more or less the same, average waking times differed. Participants woke, on average, at 7.35am after the prolonged sitting intervention and 8.06am after regular activity breaks.
And researchers found another benefit, too.
“Other research by our group and others, that also interrupted evening sitting with two to three minutes of activity every 30 minutes, found improvements in the amount of sugar in the bloodstream after a meal,” said Ms Gale.
That is important because poor sleep is associated with an increased risk of cardiometabolic disorders, such as coronary heart disease and Type 2 diabetes, said researchers.
“So from these perspectives, two to three minutes of activity, every 30 minutes, seems like a good target,” she added.
“The main thing is any interruption to sitting is better than none and this can be whatever works best for you and your household.”
Evening exercise may help improve sleep but a study from last year found that taking exercise in the morning may be the most effective way to burn fat.
Researchers found that mice that exercised in an early active phase – which corresponds to morning exercise in humans – increased their metabolism more than mice that exercised at a time when they usually rest.