The efficiency of oxygen delivery to tissues is a factor that influences the severity of major diseases such as Covid-19 and heart conditions.
Scientists already know that the ratio between the length of a person's index and ring fingers, known as the 2D:4D ratio, correlates with distance running performance, age at the time of the heart attack and the severity of Covid. -19.
Now Professor John Manning, an expert on digit ratios at Swansea University, has been working with colleagues to take a closer look at the issue.
Their findings have just been published by the American Journal of Human Biology.
The research looked at 133 professional soccer players as they underwent a series of body measurements that included measuring digit length from hand scans. They also completed an incremental cardiopulmonary test to exhaustion on a treadmill.
Professor Manning, from the Applied Sports, Technology, Exercise and Medicine (A-STEM) research team, said: “With our partners at the University of Central Lancashire's Cyprus campus, we have clarified the relationship between 2D:4D and the oxygen metabolism in a sample of well-trained athletes.
“Players with long ring fingers (4D) relative to their index fingers (2D) have efficient oxygen metabolism, such that they achieve very high maximal oxygen consumption in an incremental cardiopulmonary test to exhaustion on a treadmill” .
Long ring fingers relative to the index fingers are thought to be a marker of high testosterone levels in utero. Testosterone has effects on oxygen metabolism through its influence on energy producers (mitochondria) within cells.
He added: “Our findings are consistent with those in distance running, where long 4D is linked to high performance, and heart disease and Covid-19, where long 4D is linked to low disease severity.
“Overall, our study illustrates the value of using healthy, well-trained athletes to elucidate metabolic processes that are important in disease outcomes.”
The team says further work is now needed to quantify these associations in women.
Professor Manning's previous research has examined how the difference in finger length between a person's left and right hand can provide vital information about the outcomes of contracting Covid-19.