Increasing Non-Exercise Physical Activity With Training Reduces Chance Of Non-Response To Exercise

Abstract

Evidence of cardiorespiratory fitness (CRF) non-response is growing in both clinical and exercise training studies. Along with aerobic training, an increase in non-exercise physical activity may reduce CRF non-response contingency. PURPOSE: To determine if increases in non-exercise physical activity mitigates CRF non-response to exercise training among sedentary, overweight/obese adults. METHODS: Thirty-six adults (age: 54.19±7.14 years; BMI: 35.83±4.66 kg/m2; 77.8% female) were assessed from a previous exercise study (>70% adherence to 4 weekly sessions across 24 weeks). Participants were randomized to an aerobic training group or an aerobic training and increasing non-exercise physical activity group (increase 1,000 to 3,000 steps per day from baseline). Both groups performed the same supervised aerobic training (50-75% VO2 max) for 24 weeks at a dose of 12 kcals per kg per week. CRF non-response was determined via calculated delta (∆) values (follow-up minus baseline values) for absolute VO2 max (L/min) and participants were categorized as non-responders via technical error (TE) (∆<0.71 L/min) and classical measures (∆<0 L/min). Pearson Chi-square test of independence was conducted for categorical variables (i.e. responders vs. non-responders) in TE and classical non-responders, separately. A binary multivariable logistic regression was used to estimate odds of CRF non-response based on baseline demographic factors (age, race, BMI, fitness, waist circumference). RESULTS: Participants increasing non-exercise physical activity with aerobic training were significantly more likely to increase CRF based on TE analysis, X2 (2, N=36) =10.99, p=.004, compared to aerobic training alone. Whereas, classic non-response did not show a significant relationship X2 (2, N=36) =2.77, p=.251. Baseline age (p<.05) was a significant predictor of TE response, while baseline BMI (p<.05) was a significant predictor for classic response. CONCLUSION: Increasing non-exercise physical activity concurrent with aerobic training may improve likeliness of increasing CRF and, thus, reduce risk of cardiovascular disease and mortality. Supported by a grant from the American Heart Association (13SDG17140091).