Can your finger length predict your running ability?

We obsess over our feet and stride mechanics, but few runners ever consider their fingers as an indication of their endurance ability. New research from the University of South Australia and the University of North Dakota says maybe we should. Their recent meta-analysis—pulling data from over 5,000 people across 12 countries—suggests that the length of your ring finger compared to your index finger might offer a clue to how well you’re built for distance. The findings, published in the American Journal of Human Biology, point to a measurement known as the 2D:4D ratio.

What the numbers actually mean

The 2D:4D ratio compares the length of your index finger to your ring finger. A lower ratio—when the ring finger is longer—is linked to higher exposure to testosterone in the womb. That early hormone environment may shape everything from your cardiovascular system to your response to physical stress later in life.

In the study, runners with lower digit ratios were better at holding higher intensities before fatigue set in—a trait known as exercise tolerance. It’s not about speed or VO₂ max, but how long you can keep going when things get tough. For marathoners, that’s the whole game. One of the study’s lead researchers, Bethany Gower, called the link “significant” for both performance and potential.

Should you measure yours?

The research team suggests that the 2D:4D ratio could provide a quick, non-invasive insight into how well someone might handle endurance training. Checking your ratio is simple: hold your hand out flat and compare the lengths of your index and ring fingers. If the ring finger sticks out longer, you’ve got what’s considered a lower digit ratio.

While your finger-length ratio won’t replace training, consistency or a focus on smart recovery, it does suggest an interesting way some people might be wired to handle more from the start.