6. Respiratory Disease, Dementia & Alzheimers
An enjoyable and relaxing activity that can be tolerated by most people due to its good safety profile, sauna bathing has long been utilised as a method of defence against various respiratory diseases . These have included many common conditions both chronic and acute, including: the common cold, asthma, pneumonia, and lung cancer. To understand these effects, many studies have been conducted to investigate sauna bathing as a form of treatment.
It was found that sauna bathing was indeed related to a significantly decreased risk of developing various respiratory diseases, as well as being able to relieve the symptoms of many existing conditions . Most notably, sauna reduced individuals risk of developing common colds by over 50%, and also considerably reduced respiratory effort in both asthmatics and those with chronic obstructive pulmonary disease (COPD) [2-4].
Accumulating evidence shows that sauna baths possess anti-inflammatory properties, improve impaired vascular endothelial function, and are able to reduce the oxidative stress caused by physical exertion . This oxidative stress specifically has been found to play a pivotal role in the pathogenesis of many respiratory conditions – occurring when there are more free radicals present than can be kept in balance by antioxidants . This imbalance is most notably caused by aerobic physical exertion, as oxygen in skeletal muscles increases between 100x and 200x whilst, actual oxygen uptake only increases by around 20x. Sauna combats this problem by increasing antioxidant activity in accordance with the theory of hormesis (something that produces harmful effects at moderate/high doses may produce beneficial effects at low doses) and thereby compensates for the increase in free radicals caused by exercise . It’s heat also has direct effects on lung tissue by reducing pulmonary congestion and increasing tidal volume and vital capacity .
 Kunutsor, SK; Laukkanen, T: Laukkanen, J (2017) ‘Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study’ European Journal of Epidemiology 32(12) pp. 1107-1111. Available at: https://link.springer.com/article/10.1007%2Fs10654-017-0311-6
 Cox, NJ et al (1989) ‘Sauna to transiently improve pulmonary function in patients with obstructive lung disease’ Archives of Physical Medicine and Rehabilitation 70(13) pp. 911-913. Available at: https://www.ncbi.nlm.nih.gov/pubmed/2596966
 Preisler, B et al (1990) ‘Der Einfluss der finnischen Trockensauna auf Asthma bronchiale im kindesalter’ Pneumologie 44(10) pp. 1185-1187. Available at: https://www.ncbi.nlm.nih.gov/pubmed/?term=The+influence+of+the+Finnish+dry+sauna+on+bronchial+asthma+in+childhood
 Ernst, E et al (1990) ‘Regular sauna bathing and the incidence of common colds’ Annuals of Medicine 22(4) pp. 225-227. Available at: https://www.ncbi.nlm.nih.gov/pubmed/2248758
 Sutkowy, P et al (2013) ‘The effect of a single Finnish sauna bath after aerobic exercise on the oxidative status in healthy men’ Scandinavian Journal of Clinical & Laboratory Investigation 74(2) pp. 89-94. Available at: https://www.ncbi.nlm.nih.gov/pubmed/24304490
Dementia & Alzheimers
Although this is not a benefit most people think of when sauna bathing, it is actually one with some of the most profound long-term effects. Individuals who sauna bathed four to seven times a week were 66% less likely to develop dementia and 65% less likely to develop Alzheimer’s compared to those who did not . This information comes via an extremely thorough and reliable study, with data collected from over a 20-year period and from around 2,315 individuals; it has since been referenced by numerous independent articles and studies.
Many independent researchers agree that, although the exact manner by which conditions such as dementia arise and/or develop are not entirely understood, current evidence suggests that both oxidative stress and impaired cardiovascular function and inflammation are major contributors . As our other pages on [cardiovascular health and disease] and [respiratory disease] show, sauna greatly improves both these factors. This is due to its ability to induce a reduction of high systemic and elevated blood pressure and improve vascular endothelial function – as all these factors are well-known for their associations with dementia .
Overall, the link between sauna bathing and reduced dementia and Alzheimer’s risk is openly accepted as highly biologically plausible, rather than being the result of some secondary influence (e.g. having an overall healthier lifestyle) . Still, it is important to note that only Finnish sauna bathing specifically has been linked to these benefits, due primarily to its relatively high temperatures (usually around 80-110oC) and its practicality as part of a normal daily life therapy .
 Laukkanen, T et al (2017) ‘Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men’ Age and Ageing 46(2) pp. 245-249. Available at: https://www.ncbi.nlm.nih.gov/pubmed/27932366
 Breteler, MM (2000) ‘Vascular risk factors for Alzheimer’s disease: an epidemiologic perspective’. Neurobiology of ageing 21(2) pp. 153-160. Available at: https://www.ncbi.nlm.nih.gov/pubmed/10867200
 Luurila, OJ (1992) ‘The sauna and the heart’ Journal of Internal Medicine 231(4) pp. 319-320. Available at: https://www.ncbi.nlm.nih.gov/pubmed/1588253
 Welsh, TJ; Gladman, JR; Gordon, AL (2014) ‘The treatment of hypertension in people with dementia: a systematic review of observational studies’ BMC Geriatrics 14(19). Available at: https://www.ncbi.nlm.nih.gov/pubmed/24520843
 Heinonen, I and Laukkanen, J (2018) ‘Effects of heat and cold on health, with special reference to Finnish sauna bathing’ American Journal of Physiology, Regulatory, Integrative and Comparative Physiology 314(5) pp. 629-638. Available at: https://www.ncbi.nlm.nih.gov/pubmed/29351426