STUDY FINDS HIGH PHYSICAL ACTIVITY LEVELS MAY COUNTER SERIOUS HEALTH HARMS OF POOR SLEEP

WASHINGTON

A new study has found that those who had both the poorest sleep quality and who exercised the least were most at risk of death from heart disease, stroke, and cancer, prompting the researchers to suggest a likely synergy between the two activities.The findings of the study were published in the British Journal of Sports Medicine. Both physical inactivity and poor sleep are independently associated with a heightened risk of death and/or cardiovascular disease and cancer. But it’s not clear if they might exert a combined effect on health. To explore this further, the researchers drew on information provided by 380,055 middle-aged (average age 55) men and women taking part in the UK Biobank study. The UK Biobank is tracking the long-term health of more than half a million 37-73-year-olds, who were recruited from across the UK between 2006 and 2010.Participants supplied information on their normal weekly physical activity levels, which were measured in Metabolic Equivalent of Task (MET) minutes. These are roughly equivalent to the amount of energy (calories) expended per minute of physical activity.

For example, 600 MET minutes a week is the equivalent of 150 minutes of moderate-intensity activity, or more than 75 minutes of vigorous-intensity physical activity a week. Physical activity levels were categorised as: high (1200 or more MET minutes/week); medium (600 to less than 1200); or low (1 to less than 600); and no moderate to vigorous physical activity, according to World Health Organization guidelines.

Sleep quality was categorised using a 0-5 sleep score derived from chronotype (‘night owl’ or ‘morning lark’ preference), sleep duration, insomnia, snoring, and daytime sleepiness: healthy (4+); intermediate (2-3); or poor (0-1).A dozen physical activity and sleep pattern combinations were derived from the information supplied.

Participants’ health was then tracked for an average of 11 years up to May 2020 or death, whichever came first, to assess their risk of dying from any cause as well as from all types of cardiovascular disease; coronary heart disease; stroke; all types of cancer; and lung cancer. During the monitoring period, 15,503 died: 4095 were from any type of cardiovascular disease and 9064 were from all types of cancer.Of these, 1932 people died from coronary heart disease, 359 from a brain bleed (haemorrhagic) stroke, 450 from a blood clot (ischaemic) stroke, and 1595 from lung cancer.

Some 223,445 (59 per cent) participants were in the high physical activity group; 57,771 (15 per cent) in the medium group; 39,298 (10 per cent) in the low group; and 59, 541 (16 per cent) in the no moderate to vigorous physical activity group.More than half (56 per cent) the participants had a healthy sleep pattern; 42 per cent were classified as having intermediate quality sleep, and 3 per cent were classified as poor sleepers.