Two-Thirds of Young Swimmers Dehydrated, Study Shows

Photo Submitted

About two-thirds of young athletes in a local swim club showed up for morning practice already dehydrated and never caught up with optimal hydration levels throughout the day, according to a study published in the Journal of Strength and Conditioning Research in March.

The study is part of a series looking at hydration in young athletes. In common with other athletes, many swimmers show up for practice sub-optimally hydrated, said Stavros Kavouras, associate professor, coordinator of the U of A's Exercise Science Program and lead researcher on the study. The goal of his research is to reverse that trend and encourage young people to get the fluids they need.

The study involved 46 swimmers, ages 8 to 17, on the competitive swim team AquaHawgs. Researchers checked urine samples from first thing in the morning, when arriving at practice several hours later and after the two-hour practice. Body weight and perceptions of thirst also were measured.

Researchers found that the typical way to detect dehydration, urine color and output, may not be an accurate measure of hydration in swimmers.

"Even though we have been trying for years to educate people to look at their urine color or number of visits to the bathroom in order to evaluate hydration, we observed a different effect in swimmers," Kavouras said.

"Even though urine hydration bio-markers -- urine color, volume, or urine specific gravity -- are a great way to assess day-to-day hydration, they are not accurate during or immediately after swimming."

Swimming is different than other sports because swimmers don't lose as many body fluids to sweat, Kavouras said. And swimmers don't register thirst because of the hydrostatic pressure of the water. The baroreceptors that measure pressure in the cardiovascular system signal that the body is replete with fluids, when in actuality the opposite might be happening. "The thirst perception goes away."

Researchers designed the study to look at these two factors. Finding that the concentration of urine decreased after exercise, showing that swimmers were better hydrated than when they started, was an unexpected -- and misleading - result.

Swimming decreases production of an anti-diuretic hormone, leading to a higher volume of dilute urine, Kavouras said.

"It can be confusing. Your urine sample shows that you're doing great, even if your body is not doing great," he said. "It's better to get on the scale and use body mass before and after practice as an indicator of fluids lost."




Stavros Anastassios Kavouras, associate professor
Health, Human Performance and Recreation

Bettina Lehovec, staff writer
University Relations


Writing Workshop Week Offered for Graduate Students

Vernetta Mosley, founder of Cultivate the Writer, will lead graduate students through discussions on issues related to writing during virtual writing workshops running Monday to Friday, May 17-21. 

Survey Results to Shape Chancellor's Commission on Women Priorities

The Chancellor's Commission on Women surveyed the U of A campus in early spring semester for input in setting the commission's priorities for the 2021-22 academic year.

College of Engineering Celebrates Top Students

The College of Engineering honors its outstanding students at the end of April, including the 2021 Outstanding Senior, Madeline Suellentrop.

Candidates for Dean of Libraries to Visit Campus

Kevin Garewal, associate director of collections at Harvard Law School Library, will be the second candidate to present at 2:30 p.m., Monday, May 17, in the School of Law's E.J. Ball Courtroom.

Call for Scholarly Contributions to Inquiry Journal

The Inquiry Journal, an online publication showcasing the cutting-edge undergraduate research and scholarly activity at the U of A, will resume publication in August. Submit original research by July 1. 

News Daily