Evidence-Based Complementary and Alternative Medicine

Review Article

Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review

Table 7

Repeated sauna and male fertility.


Study characteristics			Study sample		Intervention		Comparators		Health effects	Adverse side effects
Author & year	Level of evidence	Design	Pop/country		Sauna type	Duration	Comparator/controls	Outcome measures	Positive/negative/negligible	None/mild/ moderate/ severe

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

LH = luteinizing hormone; FSH = follicle stimulating hormone; PCR = polymerase chain reaction; HIF-1α = hypoxia-inducible factor I alpha; KDR = kinase insert domain; FLT1 = fms-related tyrosine kinase; VEGF = vascular endothelial growth factor; HSP90 = heat shock protein 90; HSP70 = heat shock protein 70; HSF1 = heat shock factor 1; HSF2 = heat shock factor 2; HSFY = heat shock factor Y.