Exercise may counteract health harms of too little sleep

·3-min read
A female listening to music and jogging across a bridge in Portland, Oregon.
Regular exercise has been linked to a reduced risk of depression, heart disease and even cancer. (Posed by a model, Getty Images)

Exercising regularly may counteract the effects of too little sleep, research suggests.

Insomnia is thought to affect up to a third of British adults. The odd night tossing and turning does not have any lasting health consequences. Chronic sleep issues, however, have been linked to heart disease, cancer and even an early death.

With a sedentary lifestyle associated with these same complications, scientists from the University of Sydney investigated whether exercise and sleep have a combined impact on our health.

The team analysed more than 380,000 middle-aged people over an average of 11 years.

Read more: Exercise 'partly reverses' a fatty diet

Results, published in the British Journal of Sports Medicine, suggest exercising at or above the recommended activity levels may reverse the health implications of insomnia.

This comes after scientists from the University of Sheffield reported strenuous exercise increases the risk of motor neurone disease among people who are already genetically vulnerable.

Sleepless young woman suffering from insomnia or nightmares close up, bad dreams, tired depressed female covering eyes with hands, lying on pillow in bed, feeling headache or migraine
A third of British adults endure insomnia to some extent. (Stock, Getty Images)

The scientists analysed participants, average age 55, of the UK Biobank study.

The participants provided information on their weekly exercise, measured via Metabolic Equivalent of Task (MET) minutes – roughly equivalent to the calories burned per 60 seconds of physical activity.

Six hundred MET minutes a week is equivalent to 150 minutes of moderate intensity activity or more than 75 minutes of vigorous intensity exercise a week – the minimum recommendations made by the NHS and World Health Organization (WHO).

Read more: Prescribed sleep pills ineffective long term

The participants' physical activity was categorised as: high (1,200 or more MET minutes a week), medium (600 to less than 1,200), low (one to less than 600) or no exercise.

Their sleep quality was also scored according to their shut eye duration, snoring and daytime fatigue.

The participants were followed for around 11 years up to May 2020 or their death, whichever came first.

The lower the participants' sleep score, the higher their risk of death from any cause.

Those who did no moderate or vigorous exercise and slept badly were 57% more likely to die over the study period than the participants with a high activity level and healthy shut eye habits.

The inactive-poor sleepers were also 67%, 45% and 91% more likely to die from heart disease, any cancer or lung tumours specifically, respectively.

Inactivity was found to "amplify" poor sleep across all the causes of death, aside from stroke.

Read more: Sleep for six to seven hours a night to maximise heart health

The young, female participants with a healthy body mass index were more likely to sleep well.

The same was also true for the participants who were financially comfortable, active, ate more fruit and vegetables, spent less of their day sat down and had no mental health issues.

Not smoking, working shifts or drinking excessively were also linked to sleeping well.

The scientists have stressed this was an observational study, and therefore does not prove cause and effect. The participants also self-reported the data at just one time point.

Nevertheless, the team concluded: "Physical activity levels at or above the WHO guideline (600 metabolic equivalent task mins/week) threshold eliminated most of the deleterious associations of poor sleep with mortality."

The results suggest both physical activity and sleep quality should be targeted to improve health.

"As emerging evidence supports a synergistic effect of sleep and [physical activity] on health outcomes, future trials concurrently targeting both behaviours are warranted," added the scientists.

Watch: Jennifer Garner and her mother share their exercise routine

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