There are considerable data addressing sex-related differences in cardiovascular system aging and disease risk/progression. Sex differences in cardiovascular aging are evident during resting conditions, exercise, and other acute physiological challenges (e.g., orthostasis). In conjunction with these sex-related differences-or perhaps even as an underlying cause-the impact of cardiorespiratory fitness and/or physical activity on the aging cardiovascular system also appears to be sex-specific. Potential mechanisms contributing to sex-related differences in cardiovascular aging and adaptability include changes in sex hormones with age as well as sex differences in baseline fitness and the dose of activity needed to elicit cardiovascular adaptations. The purpose of the present paper is thus to review the primary research regarding sex-specific plasticity of the cardiovascular system to fitness and physical activity in older adults. Specifically, the paper will (1) briefly review known sex differences in cardiovascular aging, (2) detail emerging evidence regarding observed cardiovascular outcomes in investigations of exercise and physical activity in older men versus women, (3) explore mechanisms underlying the differing adaptations to exercise and habitual activity in men versus women, and (4) discuss implications of these findings with respect to chronic disease risk and exercise prescription.

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The aim of the present study was to determine if leg function is associated with ventilatory efficiency during exercise in healthy older adults. 24 women and 18 men aged 60–80 years performed treadmill exercise to fatigue for calculation of ventilatory efficiency using the ratio of ventilation to carbon dioxide at the anaerobic threshold (VE/VCO2@AT). On a separate day, participants performed leg strength testing and graded single-leg knee extension exercise. The VE/VCO2@ AT was higher in women than men (33 ± 3 vs. 30 ± 3; p = 0.03). After adjustment for age and VO2max, leg strength (knee extensor isometric force) was inversely associated with VE/VCO2@ AT in women (r = −0.44, p = 0.03) while no relationships were found for men. Strength-matched women and men had similar VE/VCO2@AT indicating that the correlation between leg strength and VE/VCO2@AT was strength-but not sex-specific. During knee extensor exercise, women with lower leg strength had increased VE/VCO2 slope across 0–15 W as compared to higher strength women (38 ± 8 vs. 31 ± 3; p < 0.05), while no differences were found for men. These results find leg strength to be associated with ventilatory responses to exercise in healthy older women, a finding that might be related to lower leg strength in women than men.

The authors examined interindividual and sex-specific variation in systolic (SBP) and diastolic (DBP) blood pressure responses to graded leg-extension exercise in healthy older (60–78 yr) women (n= 21) and men (n= 19). Maximal oxygen uptake (VO2max), body composition, physical activity (accelerometry), and vascular function were measured to identify predictors of exercise BP. Neither VO2maxnor activity counts were associated with the rise in SBP or DBP during exercise in men. The strongest predictors of these responses in men were age (SBP:r2= .19,p= .05) and peak exercise leg vasodilation (DBP:r2= –.21,p< .05). In women, the modest relationship observed between VO2maxand exercise BP was abolished after adjusting for central adiposity and activity counts (best predictors, cumulativer2= .53,p< .05, for both SBP and DBP). These results suggest that determinants of variation in submaximal exercise BP responses among older adults are sex specific, with daily physical activity influencing these responses in women but not men.

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