Six weeks of high intensity interval training (HIIT) preserves aerobic capacity in sedentary older males and male masters athletes for four years: A reunion study.

Herbert, Peter and Hayes, Lawrence and Beaumont, Alexander J. and Grace, Fergal M. and Sculthorpe, N.F. (2021) Six weeks of high intensity interval training (HIIT) preserves aerobic capacity in sedentary older males and male masters athletes for four years: A reunion study. Experimental Gerontology, 150: 111373. ISSN 0531-5565

Abstract

Long-term implications of acutely increased cardiorespiratory fitness following short-term exercise interventions in older adults are unknown. In this study, we examined peak oxygen uptake (VO2peak) four 'free-living' after a high intensity interval training (HIIT) intervention. Seventeen lifelong exercisers (LEX) and 17 previously sedentary (SED) males (55-74 years of age in 2012) were tested four years (phase D) after our previous experiment which included 6-weeks of aerobic moderate intensity exercise (phase B), followed by 6-weeks of HIIT (phase C). At all stages, a standard incremental exercise protocol on a cycle ergometer was completed to determine VO2peak. SED (P = 1.000, Cohen's d = 0.01) and LEX (P = 1.000, Cohen's d = 0.11) VO2peak at phase D was not different from phase A (enrolment). SED experienced a large decrease in VO2peak from phase C to phase D (32 ± 6 ml·kg·min-1 to 27 ± 6 ml·kg·min-1 [P 2peak from phase C to phase D (42 ± 7 ml·kg·min-1 to 39 ± 9 ml·kg·min-1 [P 2peak than SED (P 2peak over the four years from 39 ± 7 ml·kg·min-1 to 36 ± 9 ml·kg·min-1 (N = 25, P 2peak from 30 ± 7 ml·kg·min-1 to 25 ± 9 ml·kg·min-1 (N = 9, P = 0.003, Cohen's d = 0.62). Four years after completing a brief period of aerobic exercise and HIIT, older males demonstrated a preservation of VO2peak, irrespective of training status (LEX or SED). However, LEX exhibited greater VO2peak than SED after 4-years of unsupervised 'free-living'. Finally, those who discontinued exercising experienced a greater reduction in VO2peak. These findings infer that to maintain aerobic capacity, 6 weeks of HIIT every four year may be sufficient, but to attenuate the decline, exercise should be maintained.