TUESDAY, Aug. 31 (HealthDay News) -- The hearts of triathletes
adapt to the rigors of training and competition by becoming more
efficient, which suggests that combining endurance and resistance
training may be the best way to achieve optimal heart health,
German researchers used MRI to examine the hearts of 26
professional male triathletes (mean age 27.9) and a control group
of 27 men who were recreationally active no more than three hours
per week (mean age 27.3).
Compared to the control group, the triathletes had larger left
atria and larger right and left ventricles. In addition, the
triathletes' left and right ventricles had greater muscle mass and
wall thickness. A triathlon is a multi-sport competition involving
swimming, cycling and running in succession.
The researchers also found that the triathletes' resting heart
rates were 17 percent lower than those of the men in the control
group. This lower resting heart rate is associated with greater
heart blood supply and more efficient heart function.
"The hearts of the triathletes in our study are stronger and able to manage the same workload with less effort," lead researcher Dr. Michael M. Lell, an associate professor at the University of Erlangen-Nuremburg, said in a Radiological Society of North America news release.
The study is published online and in the October print issue of
"The cardiac adaptations in the elite triathletes we studied were characterized by a balanced increase in left and right ventricular muscle mass, wall thickness, dilation and diastolic function," Lell said. "These adaptations reflect the nature of triathlon training, which has both endurance and resistance components."
Endurance training includes activities such as running and
swimming, while resistance training includes weightlifting, and
cycling combines both endurance and resistance, Lell explained.
Excessive training in either resistance or endurance pursuits leads
to specific heart adaptations, and extreme endurance training is
believed to be linked with an increased risk for sudden cardiac
The U.S. National Heart, Lung, and Blood Institute offers a
guide to physical activity.