To achieve the same heart-health benefits, men may need to exercise twice as much as women, according to a large study that suggests physical activity (PA) guidelines should be adapted based on biological sex.
Researchers from Xiamen University and Sun Yat-sen University in China analysed data from activity trackers worn by over 80,000 middle-aged UK Biobank volunteers, who were observed for nearly eight years. None of the participants had coronary heart disease (CHD) at the start of the study.
The team found that women who exercised for 250 minutes reduced their CHD risk by 30%, whereas men needed to exercise for 530 minutes per week – more than double – to achieve the same benefit. Women who met the recommended 150 minutes of moderate exercise per week had a 22% lower risk of developing heart disease compared to a 17% reduction observed in men.
“Compared with male individuals, females derive equivalent health benefits with only half the exercise time”, the authors write in Nature Cardiovascular Research. “The findings might have potential to encourage females to engage in physical activity”.
The study also examined a subgroup with established CHD. Among this group, women who met the exercise target were three times less likely to die during the follow-up period than men who achieved a similar level of activity. However, the authors noted that women are less likely than men to meet the exercise target.
Current NHS and WHO guidelines recommend that adults do at least 150 minutes of moderate-intensity exercise (such as brisk walking or gardening) or 75 minutes of vigorous-intensity activity per week, regardless of sex.
Similar universal guidelines are endorsed by the American Heart Association (AHA) and the European Society of Cardiology (ESC). However, the study authors caution against a one-size-fits-all approach, stating that despite uniform recommendations, ‘a substantial gender gap persists in exercise capacity and guideline adherence’, requiring further exploration.
While the precise reason for the greater benefit to women remains unclear, scientists have suggested that sex hormones, muscle fibre composition and energy metabolism may be responsible.
“Physiologically, circulating oestrogen levels are much higher in females than in males, and oestrogen can promote body fat loss during exercise”, said Dr Jiajin Chen, one of the study’s authors and a researcher at the Institute of Cardiovascular Diseases in China, in an interview with ABC News.
Dr Emily Lau, a women’s cardiovascular specialist at Massachusetts General Hospital, told The Guardian that the study “provides further evidence that one size really does not fit all. It is time to embed sex-specific strategies into guidelines and to develop tailored interventions”.
However, the authors caution that their findings should be interpreted carefully, citing several limitations. These include the lack of diversity among the UK Biobank participants, who were mostly white, wealthy, and healthy; the small number of deaths analysed in the heart disease subgroup; and the observational nature of the research, which prevents direct causality being proven.
“Biological experiments are needed to explore the mechanisms underlying sex difference in PA benefits”, they conclude.
Nevertheless, the results highlight a critical gap in prevention strategies. Globally, cardiovascular disease remains the leading cause of death in women, accounting for one in three female deaths. This is partly because women are often diagnosed later than men. Ultimately, the study strongly suggests that exercise guidelines should be adapted according to sex and age in order to more effectively prevent cardiovascular-related deaths worldwide.
