Evolutionary psychologist John Neuhoff and colleagues at The College of Wooster in Ohio said the connection between physical fitness and the brain's auditory system may have evolved to help the weak get out of the way of approaching danger.
Participants in the study listened to a tone moving toward them and pressed a button when they thought the sound had arrived directly in front of them, the researchers said.
Nearly everyone pushed the button too early, which Neuhoff interprets as an adaptation that helps human beings to anticipate and avoid danger.
The researchers also tested the fitness levels of the listeners and found that those better equipped to handle danger allowed the sound get closer.
Individuals with greater upper body strength and/or stronger cardiovascular systems waited longer to push the button, while subjects in poorer physical shape gave themselves a greater "margin of safety," Neuhoff said.
The findings are scheduled to be presented at the 157th meeting of the Acoustical Society of America, May 18-22 in Portland, Ore.