Efficacy of HIIT and HIRT in Older Adults, The

Moderate intensity continuous exercise (MICE) improves aerobic and functional fitness and prevents chronic disease and premature morbidity. Aerobic and functional fitness are validated clinical indicators of chronic disease risk. High intensity interval training (HIIT) is a time efficient and safe alternative to MICE that has positive effects on some chronic diseases and risk in younger healthy populations. Limited research has investigated HIIT in older, at-risk populations; and the health benefits of including resistance training into HIIT approaches (HIRT) is even more limited in older, at-risk adults. The purpose of this research was to determine the aerobic and functional fitness efficacy of HIIT and HIRT exercise interventions compared to MICE in older adults at-risk for chronic disease. Forty-eight adults (≥65 years) were recruited and randomized into three 8-week exercise intervention groups: MICE (active control), HIIT, and HIRT. Aerobic (VO2max) and functional fitness (functional movement screen, FMS; timed-up-and-go, TUG; floor transfer time, FTT) were measured at baseline and after 8-weeks. VO2max improved similarly in all groups (HIIT 2.2±0.3; HIRT=3.5±0.7. MICE 2.1±0.5 ml/kg/min, P<0.01). Both high-intensity groups improved in FTT (HIRT=17%, P<0.01; HIIT=12%, P<0.05) and FMS (HIRT=17%, HIIT =10%, P<0.01). Only HIRT improved in TUG (10.6%) and balance (9%). No injuries or adverse events occurred in any group. HIRT and HITT are as safe and efficacious as MICE in older adults for improving aerobic and functional fitness. HIRT appears to elicit additional functional fitness benefits, but both high-intensity approaches are safe and effective alternatives for older adults' with or at-risk for developing chronic disease.