Many people are hoping to improve their fitness following a sedentary period, but what's the most effective way to exercise? Senior Sports Lecturer and Researcher Gavin Thomas talks to us about high-intensity interval training (HIIT) and how, when it comes to exercise, a little can go a long way: 

Since 23rd March 2020 the UK government has implemented a number of lockdowns and restrictions to help slow the spread of COVID-19. This culminated with the closing of exercise facilities and fitness centres and, as a result, many people have had to adapt their exercise regime. Regardless of the challenges and restrictions of lockdown, the majority of people in the general population do not achieve the minimum recommended levels of physical activity. 

So how can we get enough exercise?

One commonly reported barrier to becoming and remaining active is lack of time. However, a potential solution is high-intensity interval training (HIIT). HIIT is a form of exercise that involves alternating short periods of intense exercise, with recovery periods and can be completed using minimal equipment and space.

It might be time to dust off your bicycle...

HIIT has been proposed as a time-efficient alternative to long aerobic exercise recommendations. However, most HIIT protocols are not actually that time-efficient because of the need to implement long recovery periods following high-intensity efforts. On the plus side, there is evidence that HIIT protocols with as few as two maximal efforts remain effective at improving a range of health markers.

An example of a marker improved by HIIT is 'maximal aerobic capacity' (known as VO2max). VO2max refers to the maximum amount of oxygen that a person can utilise during intense exercise. This measurement as a health marker is considered the strongest predictor of cardiovascular fitness and future morbidity and mortality.

What does our research show?

In collaboration with a number of different universities, we recently asked groups of sedentary individuals to complete 2, 3 or 4 HIIT sessions a week, over a 6-week period. These sessions involved 10 mins of unloaded pedalling on a bike interspersed with two all-out maximal efforts ranging between 10 and 20 seconds. Interestingly, it didn’t matter if individuals performed 2, 3 or 4 HIT sessions a week, they all improved VO2max to a similar extent (Thomas et al. 2020).

Given the health risks associated with physical inactivity, this research demonstrates that if you have been sedentary during lockdown, incorporating HIIT sessions into your exercise regime could be an option to HIITing back at your fitness levels after lockdown!    

Gavin Thomas is a senior lecturer in sport and exercise science teaching primarily on the Sports Coaching and Physical Education FdSc and Sport and Exercise Science BSc (Hons). He is an accredited sport and exercise scientist by the British Association of Sport and Exercise Sciences (BASES) and a fellow of the Higher Education Academy. His research interests are varied and include; high intensity interval training, exercising in the heat, and the experiences and perceptions of women working as strength and conditioning coaches