Who wins: the tortoise or the hare in the race for health benefits?

Posted by Liane Azevedo, Fuse staff member and Senior Lecturer in Physical Activity and Public Health, Teesside University

At the 63rd American College of Sports Medicine Annual Meeting in Boston, USA this year, an interesting debate took place which was titled ‘Who Wins: the Tortoise or the Hare?'. The debate discussed the latest research findings on a hot topic in physical activity research: what is better for your health; high intensity exercise or reducing sedentary behaviour in favour of light to moderate exercise? I was expecting a heated debate; however, the session was quite balanced with both sides presenting the pros and cons of their approach, followed by a talk on the middle ground by Tim Church suggesting that the best is exercise in moderation (the benefits of regular moderate-intensity exercise).

Let’s start with the arguments for reducing sedentary behaviour. The sedentary behaviour ‘defence’ was presented by Genevieve Healy from the University of Queensland. She talked about a study which showed that a reduction in sitting, in favour of more standing or stepping, could both promote cardio-metabolic benefits (concerning heart disease and metabolic disorders such as diabetes) to improvements in glucose and lipid metabolism (the synthesis and breakdown of glucose and fatty acids). Similar results were shown in other presentations at the conference with a number of studies also showing that interrupted sitting with walking (rather than just standing) can improve insulin response, resting blood pressure and lipid concentration. Moreover, Genevieve provided a number of examples of interventions for the workplace and for older populations, such as Small Steps, Stand Up For Health and Stand Up Australia, which have all shown to be effective

I presented evidence of this argument myself at the conference in a poster about a systematic review which we conducted on sedentary behaviour interventions for children. We found that sedentary interventions are mostly ineffective to reduce BMI (body mass index) in a mixed-weight population but can be effective for treatment of an overweight or obese population.

In the case of sedentary behaviour major questions still remain, for instance, are the risks of sedentary behaviour for cardiovascular diseases independent of physical activity? In other words, if you have a job like mine that requires you to sit for long hours and you try to compensate for this behaviour at the end of the day by doing 30-40 mins of moderate to vigorous physical activity, does this mean that you still have the same cardiovascular disease risks as, for instance, someone who does not exercise? The answer appears to be no; the risk seems lower (phew … ). However, the data in the literature is still contradictory. But it was interesting to see well known scientists in the field like Charles Matthews recognising that these behaviours might not be as independent of each other as it was originally thought when it relates to health risks.

The case for the opposite argument - that high intensity exercise is more important for your health - was made by Professor Ulrik Wisløff from the Norwegian University of Science and Technology. He presented a number of studies which showed the additional benefits of vigorous activity compared to moderate or total physical activity on a number of health indicators, such as all-cause mortality, improvement of maximum aerobic capacity and in endothelial (the inner lining of blood vessels) function, and as an effective treatment of arterial fibrillation (abnormal heart rhythm) in unhealthy patients.

The audience questioned Professor Wisløff about the risk of injury when doing high intensity exercise, how to translate these findings into physical activity guidelines, and the long term sustainability of this type of exercise. Wisløff said that in their studies there were no report of injuries, but admitted that long term sustainability still needs to be investigated. A starting point for demonstrating the feasibility of high intensity exercise in a real-life setting can be found in the study completed by Dr Kathryn Weston at Teesside University. In the study she investigated the effect of a school-based high-intensity interval training on cardio-metabolic health. She found that the high intensity exercise did not only improve some cardio-metabolic parameters but was also delivered as intended.

Therefore, I would say that the answer to the question ‘who wins the tortoise or the hare?’ is that both are winners. For some people high intensity exercise can be the most exciting way to exercise, while for others just the substitution of sedentary to light and moderate is the suitable (also it doesn’t need to be one or the other). The most important point is to choose something that will encourage you to do physical activity, because the health benefit is there for both.

Acknowledgment: Liane Azevedo would like to thank Fuse and Teesside University for the support to attend this Conference.


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