A comparison of the immediate effects of resistance, aerobic, and concurrent exercise on postexercise hypotension. The influence of resistance exercise (RE), aerobic exercise (AE), and concurrent exercise (CE) on postexercise hypotension (PEH) is not known. We investigated the immediate blood pressure (BP) lowering effects of exercise after RE, AE, and CE sessions among healthy subjects. Twenty-one men (20.7 ± 0.7 years) performed 4 experimental sessions each in a within-subject design: control (CTL-seated rest for 60 minutes), RE (3 sets at 80% 1RM for 8 exercises, including upper and lower limbs), AE (7-minutes warm-up followed by 50 minutes of cycle ergometer exercise at 65% VO₂peak and 3-minute cooldown), and CE (2 sets at 80% 1RM for 6 exercises among those which composed the RE session, plus 20 minutes of cycle ergometer exercise at 65% VO₂peak, 7-minute warm-up and 3-minute cooldown, exactly in this order). The total duration of each exercise session was approximately 60 minutes. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were assessed by ambulatory monitoring at rest (20 minutes) and every 10 minutes after the exercise during 120 minutes while in the laboratory. The duration of the decrease in SBP was longer after AE and CE (120 minutes) compared to RE (80 minutes); and for DBP after AE (50 minutes) compared to CE (40 minutes) and RE (20 minutes) (p< 0.05). The magnitude of the decrease in SBP and DBP was similar after all exercise sessions and significantly different from CTL (p < 0.05) (SBP: RE = 4.1 ± 2.0 mm Hg, AE = 6.3 ± 1.3 mm Hg, CE = 5.1 ± 2.2 mm Hg; DBP: RE = 1.8 ± 1.1 mm Hg, AE = 1.8 ± 1.0 mm Hg, CE = 1.6 ± 0.6 mm Hg). It was concluded that exercise sessions combining aerobic and resistance activities are as effective as AE sessions and more effective than RE sessions to promote PEH.

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The findings of previous studies that investigated the strength of the relationships between the percentages of maximal heart rate (%HRmax), heart rate reserve (%HRR), maximal oxygen uptake (%VO2max), and oxygen uptake reserve (%VO2R) have been equivocal. This inconsistency between studies could largely be due to differences in methodology. The purpose of this study was therefore to determine whether different VO2max test protocols and resting VO2 assessment influence the relationships between the %HRmax, %HRR, %VO2max, and %VO2R. Thirty-three young men performed maximal treadmill protocols [ramp, Bruce] to assess HRmax and VO2max. Resting VO2 was assessed as follows: a) resting VO2standard, using strict criteria [24h exercise abstention, alcohol, soft drinks, or caffeine; 8h fasting; 30min assessment]; b) resting VO2sitting and; c) resting VO2standing[both 5min before exercise testing]. The %HRR was closer to %VO2max than to %VO2R, especially in the ramp protocol (p<.05). In the Bruce protocol relationships were closer to the identity line, and there was no significant difference between %HRR and %VO2max or %VO2R. The VO2max was significantly higher in the ramp protocol compared to the Bruce protocol (p<.001). In both protocols resting VO2 assessment produced no significant differences in intercepts and slopes of %HRR-%VO2R relationships obtained from individual regression models.The %VO2R calculated using resting VO2standard was closer to %HRR compared to VO2sitting and VO2standing. The premise that %HRR is more strongly related to %VO2R than to %VO2max was not confirmed. The %VO2max should be used to prescribe aerobic exercise intensity since its association with %HRR was stronger than the %VO2R-%HRR relationship.Key words: aerobic training, physical fitness, health, linear regression, Bruce protocol, ramp protocol. 3 IntroductionExercise that is performed at an inadequately low relative intensity results in a level of physiological strain that is insufficient to stimulate favorable adaptation and enhanced fitness [27]. In the early stages of a training program, for example, previously sedentary individuals have been shown to enhance cardiorespiratory fitness by training at exercise intensities as low as 40% VO2max [5]. However, the minimal intensity that enhances cardiorespiratory fitness is positively related to the cardiorespiratory fitness of the individual [39]. The importance of exercise intensity in relation to enhancing cardiorespiratory fitness has been eloquently summarized in a review of the literature that concluded that exercise intensity, rather than training volume and frequency, was the most important factor in enhancing cardiorespiratory fitness [45]. However, relative high exercise intensities have been found to significantly reduce adherence to physical training programs [20].Accurate exercise intensity prescription is therefore important to ensure that exercise is effective in improving fitness whilst simultaneously promoting adherence to training programs. These two issues are fu...