Objectives: The objective of this study was to assess sex differences in PPG responses to short stair stepping bouts, and to describe their intensity and metabolic cost.
Design: Crossover trial.
Methods: 34 participants (age: 25.9±5.5y; women=14) underwent 4 oral glucose tolerance tests (OGTT) during rest or with stair-stepping bouts at self-selected, moderate pace for 1, 3, and 10min. Blood was collected every 15min during the OGTTs and assessed for glucose. Participants also underwent maximal aerobic capacity assessment. Expired gases were collected during capacity testing, and each stair-stepping bout.
Results: Normalized to body weight there was no significant interaction for sex with stair-stepping trials (p=0.445, ηp2=0.03), or time (p=0.069, ηp2=0.09), or trial by time (p=0.264, ηp2=0.04). Women had higher mean glucose values than men (15(CI=3, 27)%, p=0.015). iAUC also showed no interaction of sex*trial (p=0.059, ηp2=0.09). Women had higher iAUC values (meanΔ=-29(-48, -11)%, p=0.003). There was a main effect for trial with 10min showing the largest reduction from control for women (e.g. AUC -10(-6, -13)%, p<.001) and men (-8(2, 13)%, p=.010). Metabolic cost of the stair stepping bouts showed no interaction of sex*trial (p=0.715, ηp2=0.01) and no difference between sexes (meanΔ=-1.3(-5.9, 3.4)%, p=0.571). Intensity was higher for women for the 3min (60±11 vs. 48±9%VO2max, p=0.003) and 10min (67±8 vs. 54±12%VO2max, p=0.002) bouts. Moreover, both sexes underestimated the true intensity of stepping.
Conclusions: Both sexes had similar responses to short bouts of exercise, which they perceived as less intense than indicated by objective assessment. Stair stepping reduces postprandial glucose response with similar effectiveness for both sexes. ClinicalTrials.gov Identifier: NCT03400774.
Keywords: Blood glucose; Diabetes; Exercise; Hyperglycemia; Metabolic response; Sex differences.
Copyright © 2018. Published by Elsevier Ltd.