Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, C043

Oral Communications

Two popular high intensity interval training protocols elicit similar health benefits in a controlled but real world environment.

K. L. Hesketh1, S. Shepherd1, M. Cocks1, A. Wagenmakers1, J. Strauss1

1. Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom.

Introduction: Currently 40% of the UK do not meet the physical activity guidelines with a ‘lack of time' the most commonly cited barrier to sufficient physical activity. In laboratory based training interventions, high intensity interval training (HIT) offers a time-efficient alternative to moderate intensity continuous training (MICT), but its success requires expensive specialised cycle ergometers and vigorous encouragement from the researchers. Furthermore, over 100 different HIT protocols have been investigated, potentially leading to confusion within the literature and a misleading public health message. Aim: To investigate whether two popular HIT protocols, performed using readily available cycle ergometers and without encouragement improve aerobic exercise capacity, arterial stiffness, glycaemic control and body composition. Methods: Seventy nine sedentary males (n=26) and females (n=53) aged 18-65 participated (28±1 y, BMI 25±0.4 kg.m-2) in the study. In a randomised cross-over design, participants completed either 6 weeks of 30HIT (4-8x30s sprint with 120s active recovery) or 60HIT (6-10x60s sprint with 60s active recovery). Participants then completed a 4-week washout period before completing the alternative intervention. Training sessions were completed on a Wattbike, 3 times per week. VO2peak, body composition (DXA), glycaemic control (oral glucose tolerance test (OGTT)) and arterial stiffness (aortic pulse wave velocity (aPWV)) were assessed pre and post each 6-week training phase. Results: VO2peakincreased post intervention in 30HIT (36±1 to 39±1 and 60HIT (36±1 to 39±1<0.001). Body fat percentage decreased pre to post training in 30HIT (1.0%±0.5%) and 60HIT (1.7%±0.6%) (P=0.002). Arterial stiffness improved post intervention, aPWV decreased in 30HIT (5.9±0.2 to 5.7±0.1 m/s) and 60HIT (5.9±0.1 to 5.71±0.1 m/s) (P<0.003). During the OGTT there was a trend towards a reduction in glucose area under the curve pre to post (P=0.083). No differences between the intervention groups were observed for any variable (P>0.05). Conclusion: 6 weeks of 30HIT and 60HIT induce comparable improvements in aerobic capacity, body composition and arterial stiffness. Importantly, these favourable improvements were achieved using self-selected exercise intensities and without researcher encouragement. Therefore, this data suggests that either 30 or 60 second interval interventions could be used to improve health outcomes in a sedentary population in the real world.

Where applicable, experiments conform with Society ethical requirements