2013 Garolla et al. [27] | II | Single-group, longitudinal time-course study | Healthy males/Italy | 10 | Finnish sauna | 3 months | No control group | Before, after intervention, after 3 months, after 6 months’ intervention: semen analysis; plasma sex hormone levels (LH, FSH, testosterone, inhibin); sperm parameters; sperm chromatin structure analysis; sperm apoptosis; sperm heat stress gene expression with quantitative real-time PCR analysis: HIF-1α, KDR, FLT1, VEGF, HSP90, HSP70, HSF1, HSF2, HSFY | NEGATIVE - Post-intervention: lowered sperm count (93 ± 27.0 × 106 vs 223 ± 52.8 × 106, ); lowered sperm concentration (31 ± 13.1 × 106/ml vs 89 ± 29.3 × 106/ml, ); fewer motile sperm (36.1 ± 3.6% vs 58.0 ± 7.6%, ) with no differences noted by 6 months post end of sauna intervention. No significant changes in plasma sex hormones at any timepoints. Abnormal sperm parameters [decrease in normal histone-protamine replacement (), abnormal chromatin condensation (), altered mitochondrial function ()]; up-regulation of heat-stress genes [ (), KDR (), FLT1 (), VEGF ()] and up-regulation of heat shock proteins/factors [HSP90 (), HSP70 (), HSF1 (), HSF2 (), HSFY ()] directly after sauna intervention but all changes completely reversed by 6 months post ceasing sauna activity. | None |