UND faculty join international study on finger length

The following article is an version of a press release originally published by the University of South Australia and adapted to include information and quotes from UND faculty involved.

Whether it’s a personal challenge, for charity, or on your bucket list, marathons are one of the most sought-after goals for amateur and recreational runners worldwide.

Now, a world-first study from the University of South Australia and the University of North Dakota suggests that a person’s marathon potential may be identified through a simple check of their hands.

In a meta-analysis of 22 studies (representing 5293 participants and 12 countries) researchers found that a lower digit ratio – when a person’s ring finger is longer than their index finger – is a biomarker of cardiorespiratory fitness, specifically exercise tolerance and endurance performance.

Published in “Early Human Development,” the study found that children and adolescents with lower digit ratios (indicative of higher prenatal testosterone exposure) performed better on cardiorespiratory fitness assessments than those with higher ratios.

Lead researcher and UniSA professor Grant Tomkinson, who previously taught at UND, said the findings provide valuable insights into the biological mechanisms that may influence a child’s fitness potential.

“Digit ratio is widely considered a proxy for prenatal androgen exposure, particularly testosterone,” Tomkinson said.

“A lower digit ratio – that is, a longer ring finger compared to the index finger – indicates greater testosterone exposure in the womb, which is associated with better physical fitness, greater sporting ability, and higher cardiovascular efficiency.

“Essentially, the hormone environment that we’re exposed to in utero is likely to influence our health and ability outcomes throughout life.”

Samantha Peterson, associate professor and graduate program director of Medical Laboratory Science at the University, co-authored the paper, along other UND researchers, professor of Population Health Marilyn Klug and kinesiology alumnus Matthew Russell, whose work as a graduate student helped spur the study.

“As someone from a science background, the influence of testosterone in the womb on the length of fingers was familiar and of great interest to me,” Peterson said of the study’s unique focus.

“Being able to take something so simple as looking down at your hands and use it as an indication of cardiac fitness is really amazing.”

Read the full article at UND Today.