Effects Of Upper And Lower Body Fatigue Resistance Exercise Order On Myocardial Energy Expenditure

The rate pressure product [RPP = Systolic blood pressure × heart rate] has been used as an index of myocardial oxygen consumption (MVO2) and a measurement of cardiac stress. Myocardial energy expenditures during resistance exercise (RE) do reflect the metabolic strain experienced by the cardiac tissue. To date, however, little is known about the order of lower and upper body fatigue REs on myocardial energy expenditure (i.e. RPP). PURPOSE: To determine the difference of upper (UF) and lower (LF) body fatigue REs order on RPP. METHODS: 21 untrained college students (10 males, 11 females; Age: 21.1 ± 0.2 years) participated in the study. Exercise intervention consisted of 2 days (at least 72 hours apart) of 3 sets to failure chest and leg press exercises (8RM, 2 min inter-set and 5 min inter-exercise rest), randomly assigned in either UF first or LF first. HR and SBP were obtained on the right arm with an automated blood pressure machine at both pre-exercise and immediate post set completion. RPP was then calculated by absolute RPP [RPPa = systolic blood pressure × heart rate] and relative RPP [RPPr = RPPa/total weightlift]. A two-way repeated measure ANOVA was used to compare the difference of exercise order and gender on RPPa, RPPr and lift numbers (LN), with Tukey HSD Post Hoc test performed when necessary. Statistical significance was set at the P < 0.05 level. RESULTS: Except for the LN, both in men and women, UF first RPPa (29321 ± 2665 vs. 33542 ± 2080, p < 0.05) and RPPr (0.28 ± 0.1 vs. 0.36 ± 0.19, p < 0.05) were significantly greater than that of LF first exercise. However, women significantly increased RPPr than men both in UF first (0.48 ± 0.19 vs. 0.23 ± 0.07, p < 0.05) and LF first exercise (0.35 ± 0.1 vs. 0.21 ± 0.05, p < 0.05). On the other side, RPPa was significantly increased (16545 ± 3977 vs. 12776 ± 3419, p < 0.05) in men than in women when did LF first. CONCLUSION: In a fatigue RE training session, cardiac tissue experienced more metabolic stress in doing upper body first exercise. Moreover, women experienced more cardiac stress than men. Thus, upper body RE could be performed first when attempting to train cardiac tissue, but for women, especially individuals with compromised cardiovascular systems, should be cautious when doing RE.