Influence of the type of undertrousers and physical activity on scrotal temperature

Testicular temperature correlates highly with scrotal temperature. The aim of this study was to evaluate the influence of the type of undertrousers on scrotal temperature during standardized periods of sitting and walking.

Fifty volunteers without a history of infertility and normal andrological examination were included for scrotal temperature evaluation. Temperatures were measured every minute with a portable data recorder connected with two thermistor temperature sensors, which were attached on either side of the scrotum. Ambient temperature in the study room was adjusted to 20 degrees C throughout the whole experiment. All volunteers started the experiment at the same time of day. Clothing of the volunteers consisted of standardized cotton wool trousers and shirts fitting to body size. Each volunteer performed six periods of 45 min, either walking on a treadmill (3.0 km/h) or sitting, and wearing in a standardized and randomized manner either tight, loose fitting or no undertrousers respectively.

The following interactions were demonstrated by means of multivariate analysis of variance for repeated measurements: scrotal temperatures were significantly higher for tight versus loose fitting versus absent undertrousers. Furthermore, significantly lower scrotal temperatures were identified for walking versus sitting as well as for the right versus the left scrotal side.

The present study suggests that wearing tight fitting undertrousers is associated with higher scrotal and consequently testicular temperatures than wearing loose fitting undertrousers or none.