Authors
Catherine L. Jarrett, Elson S. Floyd College of Medicine, Department of Nutrition and Exercise Physiology, Washington State University, Spokane, WA
Brandon J. Sawyer, Department of Kinesiology, Point Loma Nazarene University, San Diego, CA
Wesley J. Tucker, Department of Nutrition and Food Sciences, Texas Woman’s University, Houston, TX
Dharini M. Bhammar, Center for Tobacco Research, Division of Medical Oncology, Department of Internal Medicine, The Ohio State University, Columbus, OH
Justin R. Ryder, Department of Surgery, Northwestern University Feinberg School of Medicine; Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL
Siddhartha S. Angadi, Department of Kinesiology, University of Virginia, Charlottesville VA
Glenn A. Gaesser, College of Health Solutions, Arizona State University, Phoenix, AZ
International Journal of Exercise Science 18(5): 852-863, 2025.
DOI: 10.70252/VNUF3861
Abstract
We hypothesized that an increase in nonexercise physical activity (NEPA), assessed by daily steps outside of steps accrued during supervised exercise training sessions, would be positively correlated with the change in VO2max. Females ages 18-45 yr (n = 44; 30 ± 7 yr; 67.7 ± 18.3 kg; 24.9 ± 6.4 kg/m2) completed 36 supervised training sessions on a motorized treadmill (3 sessions/week, 30 min/session) over 12 weeks, at 70% VO2max (80% max heart rate). VO2max was assessed at baseline, 4, 8, and 12 weeks, and steps outside of the supervised exercise sessions were recorded daily during each week of training with a hip-worn pedometer. For each participant, linear regression was used to determine the slope of steps/day during the 12 weeks of training. Mean VO2max increased by 8.2% (30.5 ± 5.9 ml/kg/min to 33.0 ± 5.9 ml/kg/min; range -2.65 ml/kg/min to +6.24 ml/kg/min; P < 0.001). Although mean (± Standard Deviation) steps/day did not change during the 12-week intervention, 25 participants decreased daily steps (-1624 ± 1210) and 19 participants increased daily steps (+1713 ± 1402). The change in VO2max was not different between the two groups (P = 0.74), and the correlation between Δ VO2max and the slope of the regression (steps/day) over the 12 weeks was not significant (R2 = 0.0005; P = 0.88 for ml/kg/min; R2 = 0.008, P = 0.59 for l/min). Change in NEPA, assessed by daily steps, does not impact the VO2max adaptation observed during a vigorous-intensity walking exercise program in females ages 18-45 yr.
Recommended Citation
Jarrett, Catherine L.; Sawyer, Brandon J.; Tucker, Wesley J.; Bhammar, Dharini M.; Ryder, Justin R.; Angadi, Siddhartha S.; Gaesser, Glenn A. (2025) “Change in Free-Living Daily Steps does not Affect VO2max Adaptation in Response to a Supervised Aerobic Walking Program in Females Ages 18-45,” International Journal of Exercise Science: Vol. 18 : Iss. 5, Pages 852 – 863.
DOI: https://doi.org/10.70252/VNUF3861