Introduction:
Aging is associated with increased cardiovascular disease risk including reduced aerobic capacity and increased metabolic risk factors. Aerobic exercise training improves the risk for cardiovascular disease. The optimal exercise regimen for older adults, however, remains unknown. We tested the hypothesis that high-intensity interval training (HIIT) would be more effective than isocaloric moderate-intensity continuous training (MICT) in improving aerobic capacity and metabolic risks factors in older adults.
Methods:
Thirty eight sedentary older adults (age 65±1.0 yrs; mean±SE), free of cardiovascular disease, were randomly assigned to HIIT (n=13), MICT (n=13) or non-exercise control group (n=12). HIIT consisted of cycling at alternating intensities of 90 and 70% maximal heart rate for 40 minutes while MICT consisted of cycling at 70% maximal heart rate for 47 minutes. HIIT and MICT were performed on Airdyne bicycles, 4 days/week for 8 weeks, under supervision. Aerobic capacity was assessed by peak oxygen consumption during an incremental treadmill test. Metabolic risk factors included fasting lipid profile, glucose, insulin, and insulin resistance (homeostasis model assessment; HOMA-IR). Body composition was assessed using dual-energy x-ray absorptiometry. All measures were obtained at baseline and following the intervention.
Results:
Peak oxygen consumption increased by 2.8 ml/kg/min (23.0±1.6 vs. 25.7±1.5, pre- vs. post-intervention;
P
<0.05) in HIIT, but did not change in MICT and control group (26.0±1.5 vs. 26.2±1.4 and 23.5±1.4 vs. 24.0±1.4, respectively;
P
>0.05). Insulin and HOMA-IR improved only in HIIT (-1.9±0.6μU/ml and -0.42±0.16,
P
<0.05; respectively) and these changes were negatively associated with the change in peak oxygen consumption (r=-0.37,
P
<0.05 for both). Overall, lipids, body weight, body fat, and fat-free mass did not change in response to the intervention in any of the groups (P>0.05).
Conclusions:
HIIT but not MICT improves aerobic capacity and glucose control in healthy older adults without affecting lipids or body composition.
Impact of common cardio-metabolic risk factors on fatal and non-fatal cardiovascular disease in Latin America and the Caribbean: an individual-level pooled analysis of 31 cohort studies
