Taken together, fluid loss during an ordinary sauna bath is relatively small, and it can easily be compensated by drinking a couple of glasses of water. Sauna does not induce significant changes in blood coagulation. Sauna affects the endocrine system in many ways. The findings on the behaviour ACTH and cortisol are inconsistent and no changes seem to take place in adrenaline, FSH, LH, testosterone or thyroid hormones. The hormonal changes seen in the sauna are similar to those seen in other physical stress situations.
Children can, however, take sauna baths totally safely, if some precautions are taken into account.
Finnish children belong to the healthiest in the world. Does sauna cause or prevent diseases High temperature may induce congenital malformations, especially anencephaly and open spina bifida, in some animals. In scientific literature there are some occasional descriptions of cases of these malformations in babies born to mothers, who have been in the sauna during pregnancy. A well-controlled large Finnish study, however, did not reveal any connection between the bathing habits during pregnancy and the incidence of malformations. Some strongly disputable epidemiological data have been interpreted to suggest a connection between the sauna and lung cancer.