Take a group of guys and examine their ring finger versus their index finger, and what you’ll find is that the men with longer ring fingers will perform better in sports. This pattern repeats itself from the lowest levels of Tee-ball to the upper levels of Major League Baseball. The ratio is determined by testosterone, as you may have guessed. And now, scientists have taken a look at another anthropomorphic measurement, the waist-to-height ratio, and determined that it is an accurate predictor of both serum and free testosterone levels.
But unlike the finger ratio, we can control the waist-to-height ratio (the waist part, anyway), and positively influence our testosterone levels. If we look at obesity and metabolic syndrome, we find that guys who get sloppy around the gut will often have lowered testosterone and early stages of insulin resistance. The purists in the crowd are probably screaming at their computers right now, saying that this is a chicken/egg scenario, and we don’t know if lowered testosterone increases the waist-to-height ratio or if the increased waist size caused the lower testosterone level. But I’m pretty confidant saying that for maximal testosterone levels, we should keep body fat to a minimum.
Asian Journal of Andrology. 2011 Apr 11. [Epub ahead of print]
Waist-to-height ratio as a predictor of serum testosterone in ageing men with symptoms of androgen deficiency.
Allan CA, Peverill RE, Strauss BJ, Forbes EA, McLachlan RI.
1] Prince Henry’s Institute, Clayton, Vic. 3168, Australia  Department of Obstetrics and Gynaecology, Monash University, Clayton, Vic. 3168, Australia.
The decline in serum testosterone in ageing men may be mediated in part by obesity; however, it is uncertain which measure of adiposity is most closely associated with testosterone levels. We have examined the relationships of age, adiposity and testosterone levels in ageing men with symptoms consistent with hypoandrogenism but who were otherwise in good health. We conducted a cross-sectional study of non-smoking men aged ?54 years recruited from the community and who were free of cancer or serious medical illness. Height (Ht), weight and waist circumference (WC) were measured, and body mass index (BMI) and waist-to-height (WHt) ratio were calculated. Two morning blood samples were collected for measurement of total testosterone (TT), sex hormone binding globulin (SHBG) and luteinizing hormone (LH). Free testosterone (cFT) was calculated. Multivariate linear regression analysis was performed to assess their relationship with measures of adiposity. Two hundred and seven men aged 54-86 years were studied. On univariate analysis WHt ratio was more strongly correlated with TT and cFT than either WC or BMI. Furthermore, in models of TT and cFT, the addition of Ht to WC resulted in an increase in the magnitude of the regression coefficients for both WC (inverse correlate) and Ht (positive correlate), with the contributions of both WC and Ht both being significant (P<0.05 for all). In conclusion, WHt ratio is the best anthropometric predictor of both TT and cFT in this group of healthy but symptomatic ageing men.Asian Journal of Andrology advance online publication, 11 April 2011; doi:10.1038/aja.2011.13.