Affiliation:
1. Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences University of Agder Kristiansand Norway
2. School of Sport, Exercise and Rehabilitation Sciences University of Birmingham Birmingham UK
3. Centre for Human Brain Health University of Birmingham Birmingham UK
4. School of Health and Welfare Halmstad University Halmstad Sweden
5. School of Psychology University of Birmingham Birmingham UK
Abstract
ABSTRACTBackgroundThis study aimed to investigate the effectiveness of a 6‐month home‐based high‐intensity interval training (HIIT) intervention to improve peak oxygen consumption (V̇O2peak) and lactate threshold (LT) in older adults.MethodsTwo hundred thirty‐three healthy older adults (60–84 years; 54% females) were randomly assigned to either 6‐month, thrice‐weekly home‐based HIIT (once‐weekly circuit training and twice‐weekly interval training) or a passive control group. Exercise sessions were monitored using a Polar watch and a logbook for objective and subjective data, respectively, and guided by a personal coach. The outcomes were assessed using a modified Balke protocol combining V̇O2peak and LT measures. General linear regression models assessed between‐group differences in change and within‐group changes for each outcome.ResultsThere was a significant between‐group difference in the pre‐to‐post change in V̇O2peak (difference: 1.8 [1.2; 2.3] mL/kg/min; exercise: +1.4 [1.0; 1.7] mL/kg/min [~5%]; control: −0.4 [−0.8; −0.0] mL/kg/min [approximately −1.5%]; effect size [ES]: 0.35). Compared with controls, the exercise group had lower blood lactate concentration (−0.7 [−0.9; −0.4] mmol/L, ES: 0.61), % of peak heart rate (−4.4 [−5.7; −3.0], ES: 0.64), and % of V̇O2peak (−4.5 [−6.1; −2.9], ES: 0.60) at the intensity corresponding to preintervention LT and achieved a higher treadmill stage (% incline) at LT (0.6 [0.3; 0.8]; ES: 0.47), following the intervention.ConclusionThis study highlights the effectiveness of a home‐based HIIT intervention as an accessible and equipment‐minimal strategy to induce clinically meaningful improvements in cardiorespiratory fitness in older adults. Over 6 months, the exercise group showed larger improvements in all outcomes compared with the control group. Notably, the LT outcome exhibited a more pronounced magnitude of change than V̇O2peak.