While water breaks have become standard practice in many elite competitive sports, recent Brock University graduate Jocelyn Stel (BSc ’26) says there’s one game where keeping players hydrated can be particularly challenging: beach volleyball.

“Beach volleyballers face unique heat-related challenges. They train outdoors in direct sunlight, have limited shade, and compete on very hot sand here and at international competitions,” she says. “Water stations are far from the courts and hydration monitoring is limited, so it wasn’t clear whether players were hydrating effectively. If they aren’t, both their safety and their performance are at risk.”

Stel has just finished a research project in partnership with the Canadian Sport Institute Ontario (CSIO), where she worked as part of the Canada Summer Jobs program, at Ashbridges Bay in Toronto.

The project examined the impact of high temperatures on beach volleyball players enrolled in a summer development program along with the athletes’ hydration habits.

Co-supervised by Brock University Professor of Kinesiology Toby Mündel, Stel measured the core body temperatures of 13 beach volleyball athletes over a two-week period during practices to determine their thermal strain, or how hot their bodies were getting.

To get an idea of athletes’ hydration, the players and their water bottles were weighed before and after practice so Stel could calculate their fluid intake as well as changes in their body mass and how much water they retained.

She is compiling this information into individualized reports for the 13 athletes and CSIO.

“The athlete’s data is clearly outlined in language that’s easy for them to understand,” she says. “It explains how well they hydrated on a given day, how much water they lost through sweat and gives feedback like ‘You’re doing a great job,’ or ‘You need to work on your hydration habits and be a little more mindful of how much fluids you’re drinking.’”

Chris Pignanelli — CSIO’s Lead, Sport Lab and Research and Stel’s other co-supervisor — says her work provides a foundation for scaling the organization’s services across the sport sector.

While most people know in theory that drinking fluids to hydrate is important, Pignanelli says it’s challenging to implement the science in practice.

“Jocelyn’s work has helped bridge this gap at CSIO, creating automated processes that generates individual and team reports that contain insights into hydration practices and thermal strain across single or multiple training sessions,” he says. “We hope this will help them make informed decisions involving their hydration strategies, which can include increasing fluid accessibility during training and competition.”

That increased awareness of hydration strategies is a welcomed shift in the broader sport system’s priorities, says Mündel, Canada Research Chair in Extreme Human Environments.

For example, Mündel notes FIFA recently instituted mandatory three-minute hydration breaks midway through each half of every game during the FIFA World Cup.

In the days leading up to this year’s World Cup, he urged organizers to implement further measures protecting players from heat stress based on his findings from research he and his team published a study earlier this year.

In that study, the team documented the impacts of high relative humidity, solar radiation and air temperature on player performance during FIFA’s 2025 World Cup.

Mündel is also encouraging Volleyball Canada and the world governing body (FIVB) to implement an official policy on hydration breaks.

“Like in other sports, keeping beach volleyball athletes well hydrated will ultimately support better performance and help them avoid heat-related illness, especially on days with high heat and humidity,” he says.