Equipment-free, unsupervised high intensity interval training elicits significant improvements in the physiological resilience of older adults

Abstract

Background Reduced cardiorespiratory fitness (CRF) is an independent risk factor for dependency, cognitive impairment and premature mortality. High-intensity interval training (HIIT) is a proven time-efficient stimulus for improving both CRF and other facets of cardiometabolic health also known to decline with advancing age. However, the efficacy of equipment-free, unsupervised HIIT to improve the physiological resilience of older adults is not known. Methods Thirty independent, community-dwelling older adults (71(SD: 5) years) were randomised to 4 weeks (12 sessions) equipment-free, supervised (in the laboratory (L-HIIT)) or unsupervised (at home (H-HIIT)) HIIT, or a no-intervention control (CON). HIIT involved 5, 1-minute intervals of a bodyweight exercise each interspersed with 90-seconds recovery. CRF, exercise tolerance, blood pressure (BP), body composition, muscle architecture, circulating lipids and glucose tolerance were assessed at baseline and after the intervention period. Results When compared to the control group, both HIIT protocols improved the primary outcome of CRF ((via anaerobic threshold) mean difference, L-HIIT: +2.27, H-HIIT: +2.29, both p < 0.01) in addition to exercise tolerance, systolic BP, total cholesterol, non-HDL cholesterol and m. vastus lateralis pennation angle, to the same extent. There was no improvement in these parameters in CON. There was no change in diastolic BP, glucose tolerance, whole-body composition or HDL cholesterol in any of the groups. Conclusions This is the first study to show that short-term, time-efficient, equipment-free, HIIT is able to elicit improvements in the CRF of older adults irrespective of supervision status. Unsupervised HIIT may offer a novel approach to improve the physiological resilience of older adults, combating age-associated physiological decline, the rise of inactivity and the additional challenges currently posed by the COVID-19 pandemic. Trial registration This study was registered at clinicaltrials.gov and coded: NCT03473990.

Body composition, cardiorespiratory fitness, and neuromuscular adaptations induced by a home-based whole-body high intensity interval training

“… 26 , 48 , 49 Total lean mass was not significantly changed after WB-HIIT. This result is in agreement with previous studies showing mitigated effects of supervised 44 , 46 , 48 , 49 , 50 and home-based 26 , 27 , 30 WB-HIIT on total lean mass.…”

“…The VO 2 peak improvement after WB-HIIT is consistent with previous studies using either supervised 44 , 45 , 48 , 49 , 50 , 58 , 59 , 60 or home-based WB-HIIT. 26 , 28 , 30 The slight increase observed for VO 2 peak (5%) could be due to the short time spent at high intensity (see Table 3 ). This is in line with a recent study showing that oxygen consumption is lower during WB-HIIT compared to a running HIIT with a similar exercise to rest ratio.…”

“… 34 , 65 , 66 To our knowledge, only two studies assessed VT1 change after home-based WB-HIIT, and reported a significant increase. 28 , 30 Given the low impact of WB-HIIT on VO 2 peak, VT1 enhancement is most probably due to an improvement in muscle aerobic capacity, rather than a greater ability of the cardiorespiratory system to deliver oxygen to the muscles. 66…”

“… 25 However, only a few studies used home-based interventions. 26 , 27 , 28 , 29 , 30 In addition, none investigated the neuromuscular function (i.e., maximal strength and associated volitional drive, and endurance time during a submaximal contraction). There is then no evidence that home-based WB-HIIT could simultaneously improve body composition, cardiorespiratory fitness, and neuromuscular function.…”

Correction: Equipment-free, unsupervised high intensity interval training elicits significant improvements in the physiological resilience of older adults

“…After publication of this article [ 1 ], the authors reported that the wrong Supplementary file was originally published with this article; it has now been replaced with the correct file.…”