Retention time of sperm suspensions with improved motility following H
treatment. Twelve sperm suspensions were treated with H2- or N2-mixed gases for 30 min (first treatment) and then retreated after 24 h, (second treatment), as indicated by hatching. Before and after the treatment, the suspension was kept at 25°C in room air. The average % of motile sperm per 1 mL of sperm suspension at the indicated times was calculated. Data represent means ± standard deviation (SD). ***P < 0.001; versus suspensions just before treatment (time = 0).