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Approximately 90% of Australians with MS are affected by the heat, which can lead to heat-induced or heat-related fatigue. Heat-related fatigue can result in loss of employment and significant increase in the cost of living.Â
Recently, Associate Professor Ollie Jay and his team have shown that if certain parts of the body are cooled, the sensation of fatigue can be reduced, allowing physical activity in the heat to be performed for longer periods of time. In this project, he aimed to build on these findings and develop simple and novel interventions for preventing heat-related fatigue in people with MS.Â
Associate Professor Jay assessed if swirling cold fluids in the mouth is enough, or if they need to be swallowed. He also tested whether particular skin sites could be targeted with surface cooling materials to reduce heat-related fatigue, and if methanol can be rinsed in the mouth or applied to the skin to reduce heat-related fatigue.Â
The results from these experiments will lead to the development of novel cooling interventions that are simple and inexpensive. Ultimately, the findings of this study will not only help people with MS maintain their functional capacity for longer during exposure to the heat, but also help us better understand the underlying mechanisms associated with heat sensitivity in MS.Â
Associate Professor Jay and his team have completed data collection for the first of three studies planned in total. Information has been recorded from 21 participants who completed three experimental trials for this study.
Preliminary findings have shown that cold water swilling does not measurably improve health-related fatigue or increase exercise capacity in the heat in people with MS with heat sensitivity. This observation has led to the investigators changing the next part of their experiment to a different intervention. Associate Professor Jay will instead test alternative methods to alleviate heat related fatigue in MS: namely, aspirin, and a menthol spray to cool the skin.  Due to unforeseen factors, including the COVID-pandemic, these have been difficult to source and have delayed study progression. The research team is hoping to address these issues in 2022 and restart the timeline.
Despite the change in direction based on early findings, Associate Professor Jay’s work will result in clarity on ways people with MS can combat heat-related fatigue. Enrolment of patients in 2021/2022 has been significantly affected by the COVID-19 pandemic. The study has been extended to allow more time to complete the remaining aims and objectives.
Associate Professor Jay and his team used a climate chamber to assess the effectiveness of drinking cold-water vs cold-water mouth-swilling for reducing heat related MS symptoms during physical activity in the heat, in people with MS. They found that cold-water mouth-swilling does not help improve exercise capacity of people with MS in the heat in the same way that swallowing cold-water does, providing evidence that the best internal cooling strategy is drinking cold water. It was found that the cold water needs to be <5ËšC to achieve the best effect.Â
A second experiment tested whether local external cooling of the skin in the most temperature-sensitive region of the body (lower back) is effective at reducing heat-related MS symptoms, separate to rises in core temperature whole-body heating. Results showed that skin cooling alone is not sufficient to alter heat-related MS symptoms. These findings support the traditional view that rises in core temperature in people with MS are the main cause of heat sensitivity, with little contribution from skin temperature. The practical outcome of this finding is that recommended cooling strategies for people with MS in the heat should focus on reducing core temperature rather than focussing on surface skin cooling.Â
A third study assessed the effectiveness of external cooling using a cold-water spray on the skin to improve exercise tolerance of people with MS in the heat. Early data indicated that cold-water spraying may provide sufficient evaporative loss to achieve benefits (reduction in skin temperature of >1ËšC and reductions in core temperature of up to 0.2ËšC) and a reduction in worsening symptoms associated with an increase in core body temperature. Further research on a greater number of participants is required to confirm this early observation.Â
Associate Professor Jay and his team have published several papers on this work with addition manuscripts in preparation. Â
Updated 31 March 2024
Updated: 05 January, 2018
$176,000
3 years
