Sex Dimorphism of VO Trainability: A Systematic Review and Meta-analysis.

BACKGROUND

Increases in maximal oxygen uptake (VO) are strongly associated with improved cardiovascular health.

OBJECTIVE

The aim was to perform a systematic review and meta-analysis to determine whether VO responses to endurance training (ET), the most effective intervention to improve VO, are influenced by sex.

METHODS

We conducted a systematic search of MEDLINE and Web of Science since their inceptions until February 2019 for articles assessing the VO response to a given sex-matched dose of ET in healthy age-matched men and women. Meta-analyses were performed to determine the mean difference between VO responses in men versus women. Subgroup and meta-regression analyses were used to assess potential moderating factors.

RESULTS

After systematic review, eight studies met the inclusion criteria. All studies implemented common modalities of ET in healthy untrained individuals, comprising a total of 175 men and women (90 ♂, 85 ♀). ET duration and intensity were sex-matched in all studies. After data pooling, ET induced substantially larger increases in absolute VO in men compared with women (mean difference = + 191 ml·min, 95% CI 99, 283; P < 0.001). A greater effect of ET on relative VO was also observed in men versus women (mean difference = + 1.95 ml·min·kg, 95% CI 0.76, 3.15; P = 0.001). No heterogeneity was detected among studies (I = 0%, P ≥ 0.59); the meta-analytical results were robust to potential moderating factors.

CONCLUSION

Pooled evidence demonstrates greater improvements in VO in healthy men compared with women in response to a given dose of ET, suggesting the presence of sexual dimorphism in the trainability of aerobic capacity.