Exercise and incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and site-specific cancers: prospective cohort study of 257 854 adults in South Korea.

OBJECTIVE

The objective of this study was to examine the longitudinal associations of exercise frequency with the incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and 10 different cancer outcomes.

DESIGN

A prospective cohort study.

SETTING

Physical examination data linked with the entire South Korean population's health insurance system: from 2002 to 2015.

PARTICIPANTS

257 854 South Korean adults who provided up to 7 repeat measures of exercise (defined as exercises causing sweat) and confounders.

PRIMARY OUTCOME MEASURES: Each disease incidence was defined using both fatal and non-fatal health records (a median follow-up period of 13 years).

RESULTS

Compared with no exercise category, the middle categories of exercise frequency (3-4 or 5-6 times/week) showed the lowest risk of myocardial infarction (HR 0.79; 95% CI 0.70 to 0.90), stroke (HR 0.80; 95% CI 0.73 to 0.89), hypertension (HR 0.86; 95% CI 0.85 to 0.88), type 2 diabetes (HR 0.87; 95% CI 0.84 to 0.89), stomach (HR 0.87; 95% CI 0.79 to 0.96), lung (HR 0.80; 95% CI 0.71 to 0.91), liver (HR 0.85; 95% CI 0.75 to 0.98) and head and neck cancers (HR 0.76; 95% CI 0.63 to 0.93; for 1-2 times/week), exhibiting J-shaped associations. There was, in general, little evidence of effect modification by body mass index, smoking, alcohol consumption, family history of disease and sex in these associations.

CONCLUSIONS

Moderate levels of sweat-inducing exercise showed the lowest risk of myocardial infarction, stroke, hypertension, type 2 diabetes, stomach, lung, liver and head and neck cancers. Public health and lifestyle interventions should, therefore, promote moderate levels of sweat-causing exercise as a behavioural prevention strategy for non-communicable diseases in a wider population of East Asians.