Maximal cardiac function in sedentary normal men and women: comparison of age-related changes

Abstract

The normal range of maximal values for oxygen consumption, heart rate, cardiac index, and stroke index during treadmill exercise testing are presented for 98 men and 104 women for ages 20-75 yr. These variables decrease with age in both sexes, but men show a significantly greater reduction than women with respect to oxygen consumption (P = 0.05), heart rate (P less than 0.02), and cardiac index (P less than 0.02). Comparison of the normal ranges of oxygen consumption, cardiac index, and stroke index indicated that men have significantly higher values than women (P less than 0.001). The normal range of heart rate was higher in younger men than women, but because of a more rapid decline with age in men, the older women had higher heart rates than the older men. Invasive measurements of cardiac index in 12 normal men and 11 normal women were within the defined normal range. These measurements showed that there was a greater increase in stroke index from supine rest to maximal upright exercise in men compared with the increase in women (means +/- SD, 12 +/- 9 m/m2 vs. 2 +/- 7 ml/m2, P less than 0.01).

Exercise‐induced aortic flow parameters in early postmenopausal women and middle‐aged men

“…The heart rate results in the current report concur with those of prior studies which show higher values in women both at rest and during dynamic exercise [15][16][17]. However, our blood pressure results do not agree with previous data.…”

Modelling the influence of fat-free mass and physical activity on the decline in maximal oxygen uptake with age in older humans

“…The reduction of aerobic power with advancing age might be either a consequence of the loss of cardiovascular function (Hossack & Bruce, 1982;Hagberg et al 1985;Lakatta, 1993;Petrella et al 1994) or the loss of muscle mass (Fleg & Lakatta, 1988;Winter et al 1991;Toth et al 1993;Jackson et al 1995;Johnson et al 2000). In order to study this question we extended our previous analyses of the data based on 146 women and 152 men, between 55 and 86 years of age.…”

“…The continued decline in ýOµ,max suggests a decline in muscle oxidative power and loss of cardiovascular capacity not accounted for by our techniques. The reduction in maximal heart rate with advancing age, the loss of stroke volume (Hagberg et al 1985) attributed to a reduction in total blood volume (Davy & Seals, 1994), reduced diastolic function (Petrella et al 1994), increased afterload and a reduction in contractility during exercise (Lakatta, 1993) have been implicated in the reduction of aerobic power (Hossack & Bruce, 1982;Hagberg et al 1985). In addition, Hagberg et al (1985) examined the haemodynamic responses of master athletes, young athletes and older sedentary subjects during both submaximal and maximal exercise and found that the maximal arteriovenous oxygen difference was lower in sedentary older subjects than in the other subject groups.…”

Reduced muscle oxidative capacity is independent of O2 availability in elderly people

“…Although the mechanistic basis for this age-related decline in physical performance is complex, alterations in the capacity to transport, exchange, and utilize O 2 are believed to play a major role. Indeed, it is well known that aging is associated with reduced maximal heart rate (Fleg et al 1995) and cardiac output (Hossack and Bruce 1982), as well as peripheral hemodynamic alterations such as reduced limb blood flow, and vascular conductance Proctor and Parker 2006;Russell et al 2003). In combination, these age-related changes likely alter both convective and diffusive components of O 2 transport to skeletal muscle and contribute to a reduction in exercise capacity .…”