Clinical Trials

Does a cool drink during exercise in the heat mitigate thermal strain for MS participants

Type of Study/Intervention


Recruitment Status


Form of MS

Relapsing remitting MS, Secondary progressive MS, Primary progressive MS

Brief summary

Heat sensitivities and related fatigue have been very well documented, and it is generally believed that elevations in internal body temperature of 0.5 to 1.0°C lead to the onset of fatigue-like symptoms in individuals with MS. Behavioural strategies can be employed to help mitigate elevations in internal body temperature and associated fatigue. In healthy individuals, cold fluid ingestion during exercise has been repeatedly demonstrated to mitigate decrements in physical performance in hot environments. The optimal fluid temperature in terms of performance and human heat balance appears to be between 5 and 15°C, as iced water (~1°C) ingestion can cause a disproportionate reduction in sweating relative to the ingested internal heat sink. Whether such a simple intervention such as drinking cold water can help mitigate the onset of fatigue symptoms in individuals with MS during physical activity in the heat has not yet been elucidated.

This research will assess physiological and subjective thermal strain in participants with multiple sclerosis (MS) exercising in a warm environment while ingesting water of different temperatures. Specifically, we will examine whether core temperature and sweating, as well perceptions of exertion and thermal sensation are different following the ingestion or mouth swill of cold (7°C) water compared to thermoneutral (37°C) water.

This research will be conducted at the Thermal Ergonomics Laboratory, University of Sydney (Cumberland Campus, Lidcombe) by Dr Ollie Jay. During the study, participants will be asked to exercise on 4 separate occasions on a semi-recumbent bike at a moderate intensity and at an ambient temperature of 35°C and 30% relative humidity and 18°C, 30% relative humidity. Involvement time will be approximately 90 min for each session.

Inclusion criteria

People between the ages of 18 – 60 (male or female) who have been clinically diagnosed with MS with an EDSS between 0 – 5. NB: General practitioners will be contacted to request health information required for this study.

Exclusion criteria

You cannot participate if:
You are a current smoker, or have regularly smoked within the past two years.
You are currently taking competitive muscarinic receptor antagonists
You have experienced an exacerbation within the past 3 months
You are currently pregnant

Recruitment contacts

For more information, and to take part in the study, please contact Dr Ollie Jay (

Last updated

19 Nov 2020

Contact Us

We're not around right now. But you can send us an email and we'll get back to you, asap.

Start typing and press Enter to search