26 SHOULD TIME ELAPSED SINCE MENOPAUSE BE CONSIDERED DURING CARDIORESPIRATORY EXERCISE PRESCRIPTION IN POSTMENOPAUSAL WOMEN?

Abstract

The purpose of this study was to consider the menopausal characteristic of time elapsed since menopause (TM) and the cardiorespiratory exercise intensity guidelines of 40% 75% heart rate (HR) reserve (ACSM, 2010) and compare it to the specific cardiorespiratory training zone based on ventilatory threshold (VT). Sixty-one postmenopausal women (59.90±4.45 yr; 29.26±4.58 ml kg−1 min−1) were randomly assigned to this study. Data related to menopause was obtained through medical history; and aerobic power (VO2max) was assessed via sub-maximal modified Balke cycle ergometry (Monark E839). Throughout the tests, (HR) and gas-exchange variables were measured using a gas analyzer system (Cosmed K4b, Rome, Italy). First (VT1) and second (VT2) ventilatory thresholds were determined by time course curves of ventilation, O2 and CO2ventilatory equivalents. Exercise intensities of 40 and 75% HR reserve assessed by Karvonen’s formula were compared with HR at VT1 and VT2, respectively. A K-means clustering analysis was used to identify TM groups and differences were evaluated by paired t-test. For women with TM <15 yrs (n=50), HR at VT1 was significantly higher than 40% HR reserve (5.27%, p<0.05). Women with TM ≥15 yrs (n=11) presented differences in VT2 significantly lower than 75% HR reserve (−6.89%, p<0.01). Study indicates that cardiorespiratory exercise intensity for postmenopausal women should consider women’s time elapsed since menopause. The target zone lower limit could be adjusted to near 45% HR reserve for women with TM< 15; and for PM with TM ≥15 yrs an upper limit of 68% of HR reserve should be prescribed.