Associations between physical activity and semen quality in young healthy men.

Objective: To evaluate whether the level of everyday physical activity is associated with semen quality in young men.

Design: Cross-sectional study.

Setting: Universities, clubs, and societies.

Patient(s): Young healthy men (aged 18-35 years) with unknown fertility (n = 177).

Interventions(s): Collection of data on medical history, lifestyle factors (physical activity, nutrition, addictions), and environmental threats (exposure of gonads to cellular phones, laptops). Collection of semen samples.

Main Outcome Measure(s): Semen parameters.

Result(s): Men who were physically more active (3rd and 4th quartiles) had a higher percentage of immotile sperm than less active subjects (1st and 2nd quartiles). The mean (95% confidence interval) percentages were, respectively: 53% (38%-69%) and 51% (41%-61%) versus 38% (28%-49%) and 39% (29%-48%). Other semen parameters were unrelated to physical effort.

Conclusion(s): Physical activity might be associated with an altered percentage of immotile sperm in young, lean, educated men who have not fathered children.