Finger Lengths Linked To Voluntary Exercise

The study also casts some doubt on a previously released study which linked digit length and male aggression.

While both situations were first thought to have been caused by exposure to elevated levels of prenatal testosterone in the womb, research conducted using lab mice yielded no concrete evidence to support that original hypothesis.

The new study, conducted using 1,000 white mice, seems to support a stronger connection between digit length, voluntary exercise and high levels of prenatal stress hormones, which was indicated by the difference in activity level between the control mice and the selectively-bred active mice.

Given the results, the findings suggest that prenatal stress rather than prenatal testosterone levels in the womb, forms a component of the inherent desire for physical activity.

"The research shows a link, or relationship, between the brain, behaviour and personality traits and the shape of the hand," said Peter Hurd, University of Alberta psychology professor and one of the lead researchers. "It opens the door to the notion that aspects of one's personality, in this case the desire to exercise, are fixed very early in life."