Influence of a Weight Loss Program on Cardiorespiratory Fitness in Obese Adults

Abstract

0523 Recent investigations show that improvements in cardiorespiratory fitness may help offset the health risks of being obese. PURPOSE: To examine changes in cardiorespiratory fitness and exercise tolerance in the moderately obese following participation in a behaviorally-based weight management program. METHODS: 101 overweight individuals (78 women and 23 men; age, 50.82 ± 7.9 yrs; weight, 90.3 ± 15.3kg; BMI, 32.5 ± 4.0; body fat (%BF), 37.9 ± 5.9%; VO2 max, 26.1 ± 6.5 ml.kg- 1.min-1) participated in a clinically based weight management program consisting of exercise, nutrition education and behavior modification. The program consisted of a 3-month intensive phase (2x/week for two hours), a 3-month tapering phase (8, 1- hour sessions) and a 6-month follow-up intervention delivered by mail. During the intensive program, subjects exercised 4 days/week (2 supervised, 2 unsupervised) at 60–70% of maximal heart rate; duration increased progressively from 15 to 45 minutes/day. Subjects underwent a maximal graded exercise test using a modified Naughton-Balke protocol at baseline, after the 3-month program and at 1 year. Heart rate and rating of perceived exertion (RPE) were recorded at each stage to determine responses to submaximal exercise. Weight and %BF were also determined at all three time points. RESULTS: Body weight and percent body fat were lower at 3 months and 1 year compared to baseline (86.0 ± 14.2, 88.0 ± 16.7kg; %BF, 35.45 ± 6.8, 35.7 ± 7.5% p<0.001). VO2max was higher than baseline at 3 months (28.5 ± 7.1 ml.kg-1.min-1 p <0.0001), but returned to baseline levels at 1 year (26.1 ± 6.5 ml.kg- 1.min-1). At both 3 months and 1 year, improvements were seen in exercise minutes to exhaustion (baseline, 8.9 ± 2.8; 3 months, 10.7 ± 3.3; 1 year, 10.1 ± 3.5 p <0.001). Submaximal exercise heart rates at stages 1–4 were significantly lower at 3 months and one year by approximately 10 bpm compared to baseline (p <0.001). RPE was also significantly lower during stages 1–4 at 3 months and one year compared to baseline levels (p<0.001). CONCLUSION: Obese men and women significantly improved their exercise tolerance and effort perception at submaximal workloads without large improvements in VO2max or BMI. When dealing with obese individuals, attention should be drawn to these positive effects as improvements in submaximal work capacity may have more relevance than increases in VO2max in counteracting the ill effects of obesity and improving quality of life.