Comparison Of Progressive High-intensity Aerobic Exercise And High-intensity Interval Training (HIIT) In Older HIV+ Adults

Abstract

HIV+ adults have 40% lower VO2peak (VO2) than age-matched healthy adults. High intensity aerobic exercise (AEX) increases VO2 in older adults. A growing body of evidence demonstrates that HIIT can serve as an effective alternative to AEX. However, data in older HIV+ adults for both modalities is very limited even though a quarter of HIV+ Americans are over 50 years old. PURPOSE: To examine the effects of progressive AEX+RT and HIIT+RT on VO2 and strength in HIV+ older adults vs. sedentary controls. METHODS: Sedentary HIV+ men 50+ years of age were randomized to AEX +RT or delayed entry control groups. AEX+RT group received 16-weeks (48 sessions) of supervised center-based training with progression to a target of 45 minutes of continuous exercise at 70-80% HRreserve. The RT protocol consisted of 6 exercises progressed to 80% of baseline 1-RM. Control participants remained sedentary. Both groups were tested at baseline and 16-weeks. The control group participants then started 16 weeks of HIIT in a cross over design. The HIIT group received the same duration of supervised training and identical RT protocol with repeated testing at 32 weeks. The HIIT protocol was performed using 4 intervals of 4 minutes of work (90-95% HRMax) separated by 3 minutes of active rest (50-60% HRmax) for a total time of 28 minutes. Paired t-test or Wilcoxon signed rank sum were used to test pre/post differences. Results are presented as mean ±SE or median (range). RESULTS: To date 8 patients have been enrolled and randomized to AEX+RT or Control with 16 week testing complete in all 8 and post-HIIT testing completed in 3. AEX+RT increased VO2peak (0.29 ±0.03 L/min, p= 0.03) and lower body strength (+37 % 1-RM, p=0.05). Post-hoc comparison showed that HITT+RT training had comparable increases in VO2peak (0.32 ±0.09 L/min, p=0.07) and lower body strength (+31 % 1-RM, p=0.05). There was a trend for increased lean mass (LM) measured by DXA after AEX+RT (1.2 kg (-1.8 to 6.1) and HITT+RT (1.5 kg (1.2 to 6.1) and decreased LM after the sedentary control period (-1.7kg (-4.1 to 1.6). Changes in cross-sectional area of the thigh support these findings. CONCLUSIONS: Progressive high-intensity AEX+RT was well tolerated and effective in older HIV+ men. HIIT may be a more time efficient option that can equally improve VO2 and strength in the growing population of older adults with HIV.