Short-term aerobic training and circulatory function in women: age and hormone-replacement therapy

Abstract

The physiological basis of training responses in women, and particularly older women, is not well understood. Short-term aerobic training (STAT) was used to probe the effects of age and hormone-replacement therapy (HRT) on women's ability to rapidly change peak uptake ( VO(2max)), plasma volume and cardiac function. A total of 39 females participated in the STAT programme: 15 younger (Y; aged 19-29 years), 12 postmenopausal women undergoing HRT and 12 non-medicating postmenopausal (PM) women (aged 60-75 years). Training consisted of ten sessions of cycling over a 2-week period, which progressed in duration from 20 to 60 min and in intensity from 60-75% of maximum heart rate. Plasma volume (PV; as determined by Evan's Blue dye dilution), VO(2max) (cycle ergometry) and cardiac function (radionuclide ventriculography) were analysed using analysis of covariance or repeated measures ANOVA. All groups demonstrated similar increase in VO(2max) (Y, 13%; PM, 17%; HRT, 13%), but without a significant change in left-ventricular ejection fraction and diastolic function or volumes during supine exercise. PV expansion was observed among the Y group (7%; P <0.05) but not the PM group (2%; P >0.05) or women undergoing HRT (1%; P >0.05). Age and hormone-replacement status did not affect the magnitude of VO(2max) change. This study suggests that STAT improves VO(2max), independent of central adaptations.

Maximal and submaximal aerobic fitness in postmenopausal women: influence of hormone-replacement therapy

“…Although this comparison is not always found in the literature, our results are consistent with those from studies of long-term HRT users (Green et al 1998;Katyal et al 2003;Lee et al 1997;Snabes et al 1996) and 2 short-term crossover studies (Katyal et al 2003;Lee et al 1997). One study reported a higher resting stroke volume (Pines et al 1991) and one a higherpeak exercise cardiac output in women taking HRT (Green et al 1998).…”

“…In our study, the average duration of HRT use was 9.4 ± 5.3 years. There appears to be no difference in _ V O 2 max between non-HRT users and short- (Kirwan et al 2004;Snabes et al 1996) and long-term HRT users (Green et al 1998;Johnson et al 2002;Katyal et al 2003;McCole et al 2000;Moreau et al 2002Moreau et al , 2003. Erickson et al (2007) reported no difference in _ V O 2 peak between short-, mid-, and long-term HRT users.…”

“…This study was not a randomized trial, and the sample size might not have had adequate power to detect small differences between those taking and not taking HRT. Previous studies of sedentary women have found no difference between HRT and non-HRT groups (Johnson et al 2002;Katyal et al 2003;Kirwan et al 2004;McCole et al 2000;Moreau et al 2003;Snabes et al 1996); however, other differences between the groups made comparisons difficult. Jurca et al (2004) reported a significantly greater _ V O 2 max in a sample of sedentary women taking HRT, but in their study, the mean BMI was 32 kgÁm -2 (obese) and the mean systolic blood pressure was elevated (140 mm Hg).…”

Effect of Exercise Training on Peak Aerobic Power, Left Ventricular Morphology, and Muscle Strength in Healthy Older Women

“…The few studies performed to date (24)(25)(26) have focused on aerobic based exercise interventions. Overall, the findings of these studies suggest that the increase in VO 2peak associated with AT is due to the improvement in peak arteriovenous oxygen difference, as no significant change was found for heart rate (24,25), end diastolic volume (24), end systolic volume (24), stroke volume (24,25), ejection fraction (24,26), or cardiac output during peak exercise (24,25). Failure of older women to increase their stroke volume after AT has been linked to the inability of the senescent female heart to develop eccentric hypertrophy (27).…”

Efeitos da terapia de reposição estrogênica nas respostas hemodinâmicas e neurais ao exercício físico agudo em mulheres no período pós-menopausa

“…O fato da terapia estrogênica não ter influenciado as respostas de capacidade aeróbia máxima (VO 2máx ), confome verificado em estudos prévios 65,66 .…”