1. Separate Effects of Intensity and Amount of Exercise on Interindividual Cardiorespiratory Fitness Response.
- Author
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Ross R, de Lannoy L, and Stotz PJ
- Subjects
- Adult, Exercise Test methods, Female, Humans, Male, Middle Aged, Monitoring, Physiologic methods, Physical Exertion, Sedentary Behavior, Treatment Outcome, Exercise Therapy methods, Obesity, Abdominal physiopathology, Obesity, Abdominal psychology, Obesity, Abdominal therapy, Physical Fitness
- Abstract
Objective: To determine the separate effects of exercise intensity and amount on interindividual cardiorespiratory fitness (CRF) response., Participants and Methods: Participants were 121 (75 females, 62%) sedentary, middle-aged (mean [SD] age, 53.2 [7.5] years), abdominally obese adults who completed at least 90% of 5 weekly exercise sessions prescribed over a 24-week intervention. Participants were randomly assigned to (1) low-amount, low-intensity exercise (LALI) (180 and 300 kcal per session for women and men, respectively, at 50% of CRF [VO 2peak]; n=39), (2) high-amount, low-intensity exercise (HALI) (360 and 600 kcal per session for women and men, respectively, at 50% of CRF; n=51), or high-amount, high-intensity exercise (HAHI) (360 and 600 kcal per session for women and men, respectively, at 75% of CRF; n=31). Cardiorespiratory fitness was measured using a treadmill test at 4, 8, 16, and 24 weeks. The study duration was September 1, 2009, through May 31, 2013., Results: Cardiorespiratory fitness increased within all 3 groups at 24 weeks (P<.001). At 24 weeks, 38.5% (15 of 39), 17.6% (9 of 51), and 0% (0 of 31) of the participants within the LALI, HALI, and HAHI groups, respectively, were CRF nonresponders. At a fixed exercise intensity, increasing exercise amount reduced the rate of nonresponse by 50% (P=.02). At a fixed amount of exercise, increasing the exercise intensity eliminated nonresponse (P=.001). Exposure to exercise decreased the number of CRF nonresponders between 4 and 8 weeks for LALI and by 16 weeks for HALI but plateaued thereafter. For HAHI, the number of CRF nonresponders decreased continually over the 24 weeks., Conclusion: For a fixed amount of exercise, increasing exercise intensity consistent with consensus recommendations eliminated CRF nonresponse. Low-intensity exercise may not be sufficient to improve CRF for a substantial proportion of sedentary obese adults., (Copyright © 2015 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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