Air-conditioned environments do not prevent deterioration of human semen quality during the summer*

Objective

To determine if air conditioning might mitigate summer reductions in semen quality.

Design

Prospective study of semen quality in summer and winter.

Setting

Normal human volunteers were studied in the setting of a fertility laboratory.

Patients, Participants

Two groups of volunteers were selected from the vicinity of New Orleans: 64 men who worked indoors during the summer in air-conditioned environments and 76 others who worked outdoors.

Interventions

None.

Main Outcome Measures

Parameters of manual semen analysis were examined for seasonal and group differences.

Results

Remarkably similar reductions in semen quality during summer as compared with winter were observed in both indoor and outdoor workers, respectively, with regard to the following parameters of semen quality: 19% and 19% in sperm concentration, 25% and 27% in total sperm per ejaculate, 17% and 20% in motile sperm concentration, 13% and 15% in percent sperm with normal morphology, and 23% and 23% in concentration of morphologically normal motile sperm.

Conclusions

These findings do not support the hypothesis that the heat of the summer is detrimental to male reproductive capacity. The available evidence suggests instead a possible role of photoperiod in causing the seasonal changes in semen quality.