Supporting scientific research at Brunel – Jay testing the effects of fluid loss on cycling performance

What happens when you put a triathlete in extreme heat and take away water? Researchers Kazuhito Watanabe and José González-Alonso at Brunel University London are measuring the effect of fluid loss on cycling performance.

They strapped CRT Athlete Jay Waghray to a recumbent bike at a fixed power output and measured variables such as cardiac output, stroke volume, heart rate, and blood flow to the limbs and brain. This is to characterise how the heart and circulatory system cope with the
stress of dehydration and respond to fluid replacement during exercise. Measurements were done with regular and limited hydration, as well as varying the temperature up to 35C Celsius.

A recumbent bike was used for this test – with Jay sporting his #CRTpink custom trisuit

A recumbent bike was used for this test – with Jay sporting his #CRTpink custom trisuit


“With the growing popularity of endurance events, it’s important we understand how human physiological function is affected by exposure to severe conditions such as prolonged exercise in hot environments” – Dr Kazuhito Watanabe.
For those training (or racing!) in scorching conditions, the implications are all too real — decreased performance, higher perceived exertion, and worse. Fluid replacement (>50% of what is lost) during exercise in high heat results in positive physiological responses that can lead to better endurance performance compared to no drinking at all.
The study is part of a series aimed at advancing our understanding of cardiovascular function in endurance sports—with some key findings in time for the Tokyo 2020 Olympic and Paralympic Games.


cardiac image (Apical 4-chamber view) collected during the trial of this study


For more information about CAMA Racing Team, please visit
For more information on the study at Brunel, please contact


1. Trangmar & González-Alonso, Exercise and Sport Sciences Reviews, 2017
2. Hydration and Human Cardiovascular Function, human-cardiovascular-
function, 2017
3. Professor José González-Alonso,
alonso, 2017

Mario La PergolaComment