INTRODUCTION:

Many health benefits are claimed by individuals and facilities promoting sauna bathing,
however the medical evidence to support these claims is not well established. This paper aims to
systematically review recent research on the effects of repeated dry sauna interventions on human
health.

METHODS:

A systematic search was made of medical databases for studies reporting on the
health effects of regular dry sauna bathing on humans from 2000 onwards. Risk of bias was
assessed according to the Cochrane Collaboration guidelines.

RESULTS:

Forty clinical studies involving
a total of 3855 participants met the inclusion criteria. Only 13 studies were randomized controlled
trials and most studies were small (n<40). Reported outcome measures were heterogeneous with
most studies reporting beneficial health effects. Only one small study (n=10) reported an adverse
health outcome of disrupted male spermatogenesis, demonstrated to be reversible when ceasing
sauna activity.

CONCLUSIONS:

Regular dry sauna bathing has potential health benefits. More data of
higher quality is needed on the frequency and extent of adverse side effects. Further study is also
needed to determine the optimal frequency and duration of distinct types of sauna bathing for
targeted health effects and the specific clinical populations who are most likely to benefit.

KEYWORDS
Finnish Sauna, Infrared Sauna, Whole body thermotherapy, Hormesis