Carried out by researchers at the Federal University of Goiás and the Federal University of Pará, Brazil and the School of Sport, Health and Social Sciences, UK, the new research analysed 41 studies involving 1,115 people for qualitative analysis and 36 studies involving 1012 people for a meta-analysis. The studies directly or indirectly compared interval training with continuous moderate intensity exercise over a period of at least four weeks.
The findings, published online today in the British Journal of Sports Medicine, showed that both interval training and a continuous moderate intensity workout reduced overall weight and percentage body fat – the percentage of fat that makes up body weight – regardless of the participants’ gender or their weight at the start of the study.
However, although there was no significant difference in percentage body fat reduction between the two types of exercise, the researchers found that interval training appeared to be more effective for weight loss than a continuous moderate intensity workout, providing a 28.5% greater reduction in weight, overall.
Moreover, sprint interval training had an even larger effect on weight loss when compared to the moderate intensity workout.
Other factors also appeared to have a positive influence on the effects of interval training, including being younger than 30, choosing walking, running, and jogging as your exercise of choice, and doing a programme for more than 12 weeks.
The authors note that as most physical activity guidelines recommend an equivalent of an hour or more of exercise each day to achieve weight (or 420 minutes or more per week), few people can find the time to achieve this.
The new findings suggest that interval training, which is an exercise done at a high intensity with regular periods of recovery, could be even more effective for weight loss results and take less time.
The two most common types of interval training are high-intensity interval training (HIIT), which has grown in popularity in recent years and includes various exercises; and sprint interval training, which includes running, jogging, speed walking, and cycling.
However, the team cautioned that although the findings suggest that sprint interval training may be the more effective of the two, the wide variety of different interval training programs included in their analysis “makes it difficult to generally recommend that one particular protocol is ‘best’ for modulating body adiposity.”
“It is important to be aware of the possible risks and caveats associated with higher intensity training,” the researchers added.
“For example, it might increase the risk of injury and impose higher cardiovascular stress. Adherence should also be examined as higher intensity protocols can result in higher discomfort.”