. 2017 Jan 13;27:3. doi: 10.1186/s12610-016-0047-2

Table 2.

Effects of increase in scrotal temperature through high elevation of whole body or scrotal temperature on sperm number in men

Authors	Heating			Nb ^a	Effect on sperm number
	Method	Daily duration	Frequency		During heating		After heating
	Method	Daily duration	Frequency		Period w ^b	Mean value	Start w	Max. value
High elevation of whole body temperature
MacLeod & Hotchkiss 1941 [79]	Steam cubicle at 43 °C	45 min OAT ^c 41 °C	Once	6	w 3–9	50% ^d	w 11	130% ^e w 15
Procope 1965 [84]	Sauna 77–90 °C	15 min RAT ^f +1 °C	8 times in 2 weeks	12	w 3–6	60%	w 8	NDA ^g
Brown-Woodman et al. 1984 [85]	Sauna 84 °C	20 min RAT +0.7 °C	Once	5	w 1–4	75%	w 8	NDA
High-intensity scrotal heating
Watanabe 1959 [80]	Scrota in water bath at 44–46 °C	30 min	1 day	5	w 5–10	70%	w 11	158% ^e w 15
			2 days	4	w 2–10	45%	w 13	NR ^h
			3 days	6	w 3–10	41%	w 11	NR
			6 days	3	w 3–11	47%	w 12	190% ^e w 14
			12 days	5	w 5–12	42%	w 13	300% ^e w 16
			Every 2 days for 12 days	4	w 5–11	56%	w 9	240% ^e w 16
Rock & Robinson 1965 [82]	150 watt lamp at 8 cm; 42 °C	30 min	14 days	4	w 4–8	63%	w 9	177% ^e w 14
Rock & Robinson 1965 [82]	150 watt lamp at 8 cm; 42 °C	30 min	28 days	3	w 3–9	57%	NDA	NDA
Wang et al. 2007 [86]; Zhu et al. 2010 [87]	Scrota in water bath at 43 °C	30 min	6 days	18	w 3 w 6	(SC) ⁱ 56% ^j 26%	w 9 w 12	(SC) 44% ^j 109%
Rao et al. 2015 [88]	Lower half body in bathtub at 43 °C	30 min	Every day for 10 days	10	w 4 <5 M/ml 4/10 w 6	(SC) 52% 30%	w8	(SC) w14 106%
Rao et al. 2015 [88]	Lower half body in bathtub at 43 °C	30 min	Every 3 days for 30 days	10	w 6 <5 M/ml 4/10 w 8	28% 12%	w10	w16 102%

Legend: ^a Nb number of men, ^b w weeks, ^c OAT oral achieved temperature, ^d mean value of total sperm number/initial total sperm number (%), ^e maximal value of total sperm number/initial total sperm number (%), ^f RAT rectal achieved temperature, ^g NDA no data available, ^h NR not reported, ⁱ SC sperm count, ^j maximal value of sperm count/initial sperm count (%)