Lifting twice a week tracked with better cholesterol ratio

Resistance exercise is widely credited with cardiometabolic benefits over and above those of aerobic training, but much of that evidence rests on questionnaires that also ask people to estimate their moderate-to-vigorous activity. Self-reported activity is prone to bias, and if the people who lift also happen to walk, cycle and move more, credit given to the weights room may really belong to their aerobic minutes. Measuring moderate-to-vigorous physical activity with a worn device instead of a questionnaire is a stricter test of independence. This analysis asked whether the link between how often adults lift and their blood pressure, cholesterol ratio and blood sugar survives that test.

The researchers ran a cross-sectional analysis within the 1970 British Cohort Study, including up to 4,881 participants aged 46-48 with outcome-specific analytical samples. Resistance exercise frequency was collected by self-report and grouped against a 'no resistance exercise' reference, while moderate-to-vigorous physical activity was captured objectively using thigh-worn accelerometry. Three cardiometabolic outcomes were examined: systolic blood pressure, the ratio of total to HDL cholesterol, and HbA1c. Multivariable linear regression expressed results as percent differences, first adjusting only for sex and device-measured activity, then adding smoking status, alcohol consumption, educational attainment, self-rated health and disability.

In the models adjusted only for sex and accelerometer-measured activity, resistance exercise frequency was inversely associated with all three outcomes. Systolic blood pressure was lower by 1.28% at 2-4 times a month and 1.12% at twice a week or more; the total-to-HDL cholesterol ratio was lower by 5.00% and 7.04% respectively; and HbA1c was lower by 3.04% and 3.03%. After adding behavioural and health-related covariates, most of these associations were attenuated. Only the cholesterol ratio held up at the highest training frequency, at 3.99% lower for those lifting at least twice weekly, meaning the blood pressure and HbA1c signals did not survive full adjustment.

Previous work suggesting resistance exercise benefits cardiometabolic health independent of aerobic activity relied largely on self-reported activity data, and this analysis was designed to check that claim against device measurement. The finding partly confirms and partly complicates the picture: independence from objectively measured aerobic activity held for all three markers, but independence from broader behavioural and health characteristics held only for the lipid ratio. Because the design is cross-sectional, it cannot separate the possibility that lifting improves lipids from the possibility that healthier people lift more. Prospective and interventional data would be needed to establish direction and to explain why lipids behaved differently from glucose and blood pressure.

This is a reason to think regular strength work sits alongside a more favourable cholesterol profile in middle age, and that the link is not merely a by-product of lifters also doing more aerobic exercise. It is weaker evidence that lifting frequency alone explains differences in blood pressure or long-term blood sugar, since those associations largely disappeared once smoking, drinking, education and general health were taken into account. The signal appeared at a fairly modest frequency rather than requiring high volumes. As a snapshot of one cohort in their late forties, it describes a pattern rather than proving a cause.