Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review

Table 2

Sauna studies of rheumatological disease/chronic pain/depression.

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
2015; Kanji et al. [50]	I	RCT	Chronic tension headache/New Zealand	37	Multiple types, sauna voucher cards	8 weeks	Control group received advice and education	NPRS (numeric pain rating scale), BDI (Beck Depression Inventory), HDI (Headache Disability Index)	Positive,; 44% reduction in HA intensity in 6 weeks of treatment arm. Mean change in headache intensity between sauna and control group = 1.27 points (95% CI 0.48–2.07; = 10.17; df = 1,117; )	None
2005; Masuda et al. [51]	I	RCT	Chronic pain/Japan	46	FIR	4 weeks	Control group received same course of behavioural counselling, CBT, rehabilitation, and exercise therapy	VAS for pain; pain behaviour assessment by researchers with 11-item questionnaire; Zung SDS (self-rating depression scale); anger scoring with CMI (Cornell Medical Index); sleep quality with simple 0–10 scoring; degree of satisfaction of treatments with simple numerical scoring; return to work 2 years after intervention	Positive,; increased likelihood of return to work 2 years later (); decrease in anger scoring in sauna group compared to control (4.5 ± 1.1 to 2.2 ± 1.6, )	Moderate,; 2 patients excluded -could not tolerate sauna - acute bronchitis and claustrophobia
2005; Masuda et al. [52]	I	RCT	Mild; depression/; Japan	28	FIR	4 weeks	Control group received placebo,; 45 min bedrest at 24°C and postrest shower in addition to the same rehab programs, physical therapy, occupational therapy	Somatic complaints with CMI (Cornell Medical Index); Zung SDS (self-rating depression scale); VAS for hunger and relaxation; plasma levels of ghrelin, glucose, catechol-amines; daily caloric intake.	Positive, improved somatic complaints (), improved hunger scores (), and improved relaxation scores () in sauna group compared to control group. Plasma ghrelin concentrations and daily caloric intake increased in sauna group (, and , , respectively); = Student 2-tailed -test	None
2009; Oosterveld et al. [53]	III	2 single-group; (side-by-side); intervention pilot trials	Rheumatoid arthritis (RA) and; ankylosing spondylitis (AS)/The Netherlands	34	FIR	4 weeks	No control group; two groups receiving same sauna intervention	VAS, EPM-ROM (Escola Paulista de Medicina range of motion), DUTCH-AIMS (Dutch arthritis impact measurement scales), BASMI (Bath Ankylosing Spondylitis functional index of range of motion), BASDAI (Bath Ankylosing Spondylitis disease activity index); serum ESR	Positive,; pain and stiffness decreased in RA () and AS () groups during sauna sessions only.	Mild-; 12−24% scoring uncomfortable on well-being scores during beginning of sauna
2015; Amano et al. [54]	III	Clinical study with control group, pilot trial	Females with chronic fatigue syndrome/myalgic encephalomyelitis/Japan	15	FIR	8 weeks	6/15 chose not to undergo sauna intervention	SF-36 survey; SRQ-D (brief self-rating questionnaire for depression); STAI (state-trait anxiety inventory questionnaire)	Positive,; 7/9 in sauna group improved during sessions; 4/9 were still improved at follow-up 9−40 months afterwards; 2/9 non-responders.; 3/6 controls receiving usual treatment improved at follow-up	Moderate-; heat intolerance in most participants,; protocol changed.
2015; Soejima et al. [55]	III	Single-group clinical study	Chronic fatigue syndrome (CFS)/Japan	10	FIR	4 weeks	No control group	Numerical rating scales for fatigue and POMS (profile of mood states) questionnaire	Positive, decreased fatigue (), improved POMS scores for anxiety (), depression (), fatigue () and performance status () after sauna	None
2011; Matsumoto et al. [56]	III	Single-group clinical study	Females with fibromyalgia and autoimmune disorders/Japan	44	FIR	12 weeks	Sauna only one part of intervention; combined with underwater exercise therapy; no control group	VAS-visual analogue scale; no. of tender pts on clinical exam; FIQ (fibromyalgia impact questionnaire); SF-36 quality of life questionnaire	Positive, reduced VAS pain scores (); fewer # of tender pts (); reduced symptoms based upon FIQ (); improved quality of life on SF-36 questionnaire (–0.05) after combined sauna + underwater exercise therapy	None

FIR = Far-infrared sauna; ESR = erythrocyte sedimentation rate; VAS = visual analogue scale; CBT = cognitive behavioural therapy.