May 19, 2026

expert reaction to study on amount of exercise done a week and benefits to heart health, using Mendelian randomisation

A study published in the British Journal of Sports Medicine uses Mendelian randomisation to look at associations between exercise and cardiovascular health.

Prof Aiden Doherty, Professor of Biomedical Informatics, University of Oxford, said:

“The press release does not accurately reflect the science in the paper. The data in the paper very clearly support current World Health Organisation physical activity guidelines. i.e. Achieving 150 minutes of moderate to vigorous intensity physical activity, irrespective of your physical fitness level, is associated with ≈8-9% lower risk of future cardiovascular disease. People who are able to do more activity have even lower risk, so every move counts.

However, it is misleading to say that people need to achieve >560 minutes (1hr 20mins per day) for health benefit.

“The underlying research is good, using world-leading datasets and well accepted methods. The authors’ conclusions in the scientific manuscript are fine (e.g. “Importantly, these findings simultaneously reinforce the public health value of the current 150 min/week guideline. The remarkably consistent relative risk reduction across all fitness strata (HR, 0.91–0.92) and the broadly overlapping CIs in figure 2A confirm that this threshold functions as a robust universal minimum that does not require fitness-­ based modification. Given that large proportions of the population do not yet meet even this benchmark77, the primary public health message remains straightforward: achieving 150 min/week of MVPA delivers meaningful cardiovascular protection regardless of fitness level.”) … the only problem is with the less careful wording in the abstract and press release text.

“We can’t give much weight to the figure of 560-610 minutes of exercise a week. Clearly there will be cardiovascular benefit for people who are able to do >1hr 20mins of moderate-to-vigorous intensity physical activity per day but this is not a sensible public health message. The public should continue to aim for at least 150 minutes of moderate to vigorous intensity of physical activity per week; more is better; every move counts.

“Public health guidelines are in a current state of transition to in future reflect evidence from studies with device-measured (rather than self-reported) physical activity levels. This exact same dataset has already been used many times (e.g.https://www.sciencedirect.com/science/article/pii/S0140673625022196?via%3Dihub… https://journals.lww.com/acsm-essr/fulltext/2026/01000/daily_steps_as_a_public_health_metric_for_physical.3.aspx).

“This work clearly contributes to the evidence base showing that it is important for people to be physically active. However, the suggested target is misguided. The public should continue to aim for at least 150 minutes of moderate to vigorous intensity of physical activity per week; more is better; every move counts.”

Prof Steffen Petersen, Professor of Cardiovascular Medicine, NIHR Barts Biomedical Research Centre, Queen Mary University of London (QMUL), said:

“This is a large, well‑conducted observational study using objective measures of both physical activity and cardiorespiratory fitness in the UK Biobank. UK Biobank is a prospective observational cohort study, but the authors used a causal inference method, Mendelian Randomisation, to get closer to causality. It shows that the amount of moderate‑to‑vigorous physical activity needed to achieve a given reduction in cardiovascular risk depends on an individual’s underlying fitness. The current recommendation of 150 minutes per week appears to be a sensible minimum threshold, but the findings suggest that higher volumes of activity are associated with greater risk reduction, particularly in people with lower fitness. A major strength of this work is the use of device‑measured activity and fitness rather than self‑report, which increases confidence in the observed dose–response relationships.”

‘Joint non-linear dose–response associations of device-measured physical activity and cardiorespiratory fitness with cardiovascular disease: a cohort and Mendelian randomisation study’ by Zhide Liang et al. was published in British Journal of Sports Medicine. at 23:30 UK time on Tuesday 19 May. 

DOI:10.1136/ bjsports-2025-111351

Declared interests

Prof Aiden Doherty: AD’s research team at Oxford is supported by a range of grants from the Wellcome Trust [223100/Z/21/Z, 227093/Z/23/Z], Swiss Re, GSK, Boehringer Ingelheim, Google, National Institutes of Health’s Oxford Cambridge Scholars Program, EPSRC Centre for Doctoral Training in Health Data Science (EP/S02428X/1),  British Heart Foundation Centre of Research Excellence (grant number RE/18/3/34214), Cancer Research UK, and funding administered by the Danish National Research Foundation in support of the Pioneer Centre for SMARTbiomed. 

Prof Steffen Petersen: Steffen Petersen, Professor of Cardiovascular Medicine at Queen Mary University of London, provides Consultancy for Circle Cardiovascular Imaging, Inc., Calgary, Alberta, Canada.