Type of exercise:
The initial 20 minutes of each session were spent walking or jogging. Subjects could then use the stationary bike, stair stepper or cross-country machine. The exercise was to be carried out 3 days each week for a minimum of 30 minutes at a workload that produced a heart rate corresponding to 60%-80% of subjects VO-2 max achieved on the graded exercise test at baseline. Progressive increases in the exercise duration and/or intensity were made at intervals over the course of training by adjusting the exercise workload to maintain the subject's heart rates within the initially prescribed ranges. Warm up and cool down exercises were performed in addition to the 30 minute aerobic exercise. Polar Vantage XL Heart Rate monitors were used during each exercise session so the subjects could be coached to keep their heart rates within the appropriate training range.
The study was a randomized, wait-listed, controlled clinical trial that began enrolling in 1995 prior to the widespread use of HAART. the last subject completed the exercise protocol in 1998. Study subjects were HIV infected adults recruited from the Infectious Disease Clinic and an associated AIDS Clinical trials Unit at a large midwestern academic medical center and from local service & social groups of HIV infected persons. 60 adults were randomized to the exercise or no exercise arms with CD4s 200-500. The exercise group completed a 12 week supervised exercise program. Control subjects continued usual activity and were enrolled in program after 12 weeks.
49 (82%) subjects completed the initial 12 weeks of the study: 19 exercise subjects and 30 no-exercise subjects. The exercise subjects participated in a minimum of 28 (78%) of the possible 36 sessions.
The exercise intervention did have a significant effect on weight, BMI, triceps skinfold, sum of the central skinfolds, sum of the peripheral skinfolds, circunfrance of the abdomen at the abdominal girth, and waist-to-hip ratio after controlling for the initial baseline values and covariates. Neither exercise nor no-exercise group had a significant change from baseline in total kilocalroies consumed, or in the percentage of carbohydrates, or protein as reported in their 4 day food diary. However, the exercise subjects did significantly reduce the percentage of fat in their diet from 35% at baseline to almost 30% at week 12, compared to no-exercise subjects who reduced percentage of fat from 36.5% to 34.6% from baseline to week 12.
Significantly decreased from baseline were: weight, body mass index, tricep skinfold, central skinfolds, peripheral skinfolds, waist at abdominal girth waist-to-hip ratio. CD4 count and percentage and HIV RNA did not change. Exercise capacity increased 11% for subjects in exercise group showing exercise improves energy and fatigue and allows for increased capacity in daily living activities. The authors said that although they were able to demonstrate a significant reduction in waist circumfrance, because the study included only 14 persons on HAART more study work needs to be done. The authors said "it would be important to assess whether central fat can be preferentially reduced without exaggerating the loss of peripheral fat
(Editorial note from Jules Levin: I don't think being on HAART would in general reduce the loss of fat in the periphery seen with exercise like this. I think such exercise entails a risk that fat loss in periphery (lipoatrophy) is a risk for some individuals byut maybe not for all. So, caution is advised: if undertaking such aerobic exercise, if you already have fat loss in the periphery, it could be increased).