Interval training overview

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Interval training is any exercise session that involves a series of low- to high-intensity exercise workouts interspersed with periods of rest. The periods of intensity are typically at or close to anaerobic exercise, while the recovery periods involve activity of lower intensity. The main aim is to improve speed and cardiovascular fitness. However, it’s high-intensity interval training (HIIT) that's associated with the most health benefits, including improved fat-burning and cardiovascular endurance.

Stop start

‘High-intensity interval training involves alternating between very intense bouts of exercise and low intensity exercise,’ says fitness expert Marc Perry ( ‘For example, sprinting for 30 seconds, then walking for 60 seconds is a type of high-intensity interval training.’

A typical HIIT session can range from a few minutes to half-an-hour comprising a variety of exercises and equipment, for example: sprinting, cycling, box-jumps and rope-jumping. The period of effort and rest can vary. Athletics coach Peter Coe set his son, double Olympic gold medallist Seb Coe, training sessions of 200m runs with just 30 seconds rest in-between. In stark contrast Jamie Timmons, professor of systems biology at the University of Loughborough, suggests doing three sets of two minutes of gentle pedalling on an exercise bike followed by 20 seconds of flat-out sprint cycling.

Steady does it?

A common thought among fitness beginners is that the more endurance cardio you do, the more weight you will shed. However, if you subject your body to regular 30 minute runs then you’ll quickly reach a plateau ensuring you’re not gaining the maximum benefits possible from your cardio training.

HIIT produces improvements in fat burning, fitness levels and resting metabolic rates compared to lower-intensity steady cardio training, judging by the results of a study carried out by Jeffrey W. King of East Tennessee State University,

A study carried out at Bowling Green State University, the University of Alabama and the University of South Carolina revealed that HIIT is optimised at a 2:1 work-to-rest ratio of training at your maximum speed for a minute, with 30 seconds of rest in between the next one-minute burst. Over a ten-minute period this would bring about improved results than endurance training, according to a study by the American College of Sports Medicine which highlighted that two weeks of HIIT would amount to the same as six to eight weeks of traditional endurance workouts.

As an additional bonus, HIIT stimulates your production of human growth hormone (HGH) by up to 450%, which encourages your body to build more muscle. So, if you want to lose weight and get ripped there's no denying that short, intense sessions  are more beneficial than longer ones that stay within your comfort zone. Just make sure to build up the intensity of your sessions gradually to avoid injury.


Alex Harris wrote for Men’s Fitness, which predated then shared a website with Coach. Alex earned a MA in journalism from Kingston University and after contributing to Men’s Fitness worked for Express Newspapers as a journalist and editor for six years.