FRIDAY, Dec. 4, 2015 (HealthDay News) -- The endurance competition known as the Ultraman could lead to muscle damage associated with insulin resistance, a new study reveals.
Ultraman athletes may also experience higher levels of the stress hormone cortisol and a drop in their testosterone levels. These negative health effects are temporary but call into question the long-term health of people who train for and compete in these races on a regular basis, researchers from Florida State University caution.
The three-day Ultraman includes an initial 6.2-mile open swim and a 90-mile bike ride. On day two, athletes complete a 172-mile bike ride, and on the final day they run a double marathon, or 52.4-miles.
During the Ultraman competition last year in Florida, researchers assessed the health of 18 athletes, including four women.
"We'd analyze the competitors on the spot," Michael Ormsbee, assistant professor of exercise science and sports nutrition at Florida State, said in a university news release. "We looked at everything we could to get a full picture of their health."
The athletes were weighed every morning before they competed. They also gave urine and blood samples so researchers could monitor their blood sugar levels and other changes in their body.
The study, recently published online in the European Journal of Applied Physiology, found that, overall, the athletes lost body fat but they didn't lose weight because they retained fluid.
The researchers also found noticeable signs of muscle damage, which suggests the competitors experienced reduced insulin sensitivity. When muscles became less sensitive to insulin, blood sugar levels increase -- a symptom associated with type 2 diabetes, the study authors said.
"Given recovery, their insulin sensitivity likely returned to normal, but it was interesting to see how a presumably healthy activity can lead to symptoms associated with being very unhealthy," one of the researchers, Daniel Baur, a Florida State graduate student, said in the news release.
Florida State's endurance coach, Chuck Kemeny, sought to understand how well the athletes were performing and how they could improve their training and preparation for the event.
"It's been very obvious that a number of athletes don't have an appreciation for nutrition," Kemeny said in the news release. "To have data on these athletes analyzed is really beneficial to future competitors."
The U.S. Centers for Disease Control and Prevention has more about the health benefits of exercise.