Scientific Programme
Sports and Exercise Medicine and Health
IS-MH09 - Improving health and wellbeing with a minimal dose of high-intensity exercise; can we make it work?
Date: 02.07.2024, Time: 12:00 - 13:15, Lecture room: Clyde Auditorium
Description
Over the past two decades, a growing body of evidence has provided support for the lab-based efficacy of (sub)maximal high-intensity interval training (HIIT) and supramaximal sprint interval training (SIT) to provide health benefits similar or greater than those associated with current physical activity recommendations. Nonetheless, there are widely-held misconceptions about HIIT/SIT; for example that a large volume of high-intensity exercise is needed to achieve health benefits, that negative affective responses will reduce enjoyment and subsequent uptake of / adherence to HIIT/SIT, and consequently, that HIIT/SIT are not feasible as ‘real-world’ interventions. The aim of this symposium is to provide an overview of recent research addressing such misconceptions. Dr Richard Metcalfe will outline how, considering the severe disruption of homeostasis with ‘all-out’ sprints, it is not surprising that reducing duration and number of sprint repetitions in classic SIT protocols does not attenuate adaptations for key health markers. Dr Niels Vollaard will expand on this by providing evidence that, despite involving all-out exercise intensities, affective responses associated with very low volume SIT are acceptable and compatible with its use as a real-world exercise intervention. Finally, Dr Jenna Gillen will give an overview of evidence suggesting that various factors can diminish or enhance observed health-related adaptations to HIIT/SIT, with implications for their application.
Chair(s)
Niels Vollaard
University of Stirling, Faculty of Health Sciences and Sport
United Kingdom
Annabel Simpson
University of the West of Scotland, School of Health and Life Sciences
United Kingdom
Speaker A
Richard Metcalfe
Swansea University, Applied Sports Technology Exercise and Medicine Research Group
United Kingdom
Read CVECSS Glasgow 2024: IS-MH09
Very low volume sprint interval exercise for improving health and fitness: what is the evidence?
Over the last ~15 years there has been considerable interest in the effects of high-intensity interval training (HIIT) upon health. Much of this research has focused on sub(maximal) HIIT protocols (e.g., 10 x 1-min efforts with 1 min recovery), as these are perceived to be more applicable for unfit and inactive individuals and/or patient populations. However, the need for multiple high-intensity efforts still makes these protocols demanding to perform, while also reducing the overall time-efficiency that is one of the key proposed benefits of HIIT. At the same time, sprint interval training (SIT) – a specific form of HIIT involving repeated ‘all-out’ sprint efforts – has been largely dismissed as a viable form of exercise for improving health. Yet, a growing body of evidence demonstrates the efficacy of SIT protocols with fewer (as little as two repetitions) and shorter (10-20 s) sprints for improving important risk factors for chronic disease. These SIT protocols involve extremely low doses of exercise (40 s per session) and a minimal total time commitment (20-30 min per week), making them shorter and easier and removing many common barriers to HIIT and to exercise in general. Nevertheless, there are many common misconceptions about very low volume SIT protocols amongst both academic researchers and practitioners. A common one is that “this cannot possibly be enough exercise to actually be effective!”. At face value this is reasonable – that as little as 40 s of exercise could elicit beneficial adaptations is an extraordinary claim. However, when viewed through the critical lens of the physiological and molecular responses to acute sprint exercise, it is a much less surprising, and even expected, finding. The purpose of this talk is to critically discuss the mechanistic basis for physiological and health-related adaptations to occur with minimal doses of sprint interval exercise. The current evidence for the effects of very low volume SIT on health and fitness parameters (e.g., cardiorespiratory fitness, insulin sensitivity, etc) will then be discussed, with avenues for future research highlighted.
Speaker B
Niels Vollaard
University of Stirling, Faculty of Health Sciences and Sport
United Kingdom
Read CVECSS Glasgow 2024: IS-MH09
Exercise at higher intensities makes people feel worse, but did we overlook the influence of shorter exercise duration?
An increasing body of evidence supports the lab-based efficacy of interval protocols involving brief repeated bouts of (sub)maximal exercise (high-intensity interval training [HIIT]) or supramaximal exercise (sprint interval training [SIT]) to improve general health and reduce risk of a range of noncommunicable diseases. However, whether HIIT and/or SIT can be used as effective real-world interventions remains a topic of debate. Concerns have been voiced that the high exercise intensities involved with HIIT and SIT will substantially decrease participants’ affective valence, reducing exercise enjoyment and self-efficacy, and ultimately leading to poor uptake and adherence. Research solely based on continuous exercise confirms links between exercise intensity and changes in affective valence, as well as between changes in affective valence and future physical activity behaviour. However, HIIT and SIT are not continuous exercise, and HIIT is not SIT: these are distinct exercise interventions encompassing widely divergent protocol parameters (e.g., sprint intensity and duration, number of repetitions, recovery interval duration, training frequency, mode of exercise). Recent evidence supports that modulating sprint duration and number of sprint repetitions can substantially alter in-task affective responses to HIIT and SIT. Moreover, emerging evidence refutes the proposed links between changes in affective valence and exercise enjoyment, as well as between changes in affective valence and future physical activity behaviour. Dr Vollaard will argue that very low volume SIT protocols may represent acceptable interventions for improving health markers in the general public and specific patient populations. This talk is intended to be of relevance to researchers with a general interest in the area of physical activity and health.
Improvements in glucose metabolism and insulin sensitivity with interval exercise: is it a HIIT in females?
High-intensity interval exercise (HIIE) is touted as a time-efficient strategy to improve indices of cardiometabolic health including glycemic control and insulin sensitivity. The benefits of HIIE on glycemic control and insulin sensitivity include improvements observed during and up to 24 hr following a single session of exercise, and those which accrue from repeated sessions of exercise over weeks or months (i.e., following chronic exercise training). While a number of studies have now documented the glycemic benefits of HIIE, there is evidence that females do not achieve the same improvements in this important health outcome as males. It has been suggested that sex differences in skeletal muscle metabolism, including cellular stress and fuel metabolism, may explain the difference in the insulin-sensitizing effects of HIIE in males and females. In this session, an overview of the effects of HIIE on glycemic control and insulin sensitivity will be provided. Dr Gillen will then highlight the evidence demonstrating sex differences in the response, providing both possible mechanisms and confounding factors in study designs that could explain these findings. Dr Gillen will also highlight recent data from her lab demonstrating that manipulating the timing and macronutrient composition of meals around exercise may be a strategy to optimize the glycemic benefits of HIIE in females. Finally, Dr Gillen will identify gaps in knowledge for future research and provide recommendations for best practices in research designs investigating both sex-based differences and women’s health in response to exercise. This talk will be of interest to researchers and practitioners with interests in exercise physiology, muscle metabolism, women’s health, nutrition, and diabetes.