Many of us know or love someone who has suffered from memory loss, severe or mild. As we age, cognitive decline can become a real concern. What can we do about it? Surely some things are out of our control, but there are many preventative measures we can take toward keeping the brain healthy. We're going to talk about one of them: sauna bathing.
Sauna bathing has been studied and recorded as a potential tool to reduce the risk of disease related to cognitive impairment!
But how does it work? First, it's important to understand two hormones which deeply impact cognitive and mental function when they are released.
Norepinephrine: a hormone and neurotransmitter produced in the brain that enhances focus and attention.
Prolactin: a hormone released by the pituitary gland that encourages faster brain function and repairs nerve cell damage by encouraging the growth of myelin (an insulating layer that forms around the spinal cord, brain, and other nerves, and allows electrical impulses to move efficiently along the nerve cells.)
Now, we'll explore what sauna has to do with these two hormones.
In one study, young men stayed in a 80°C (176°F) sauna until perceived exhaustion. Their norepinephrine levels increased by 310% and their prolactin levels increased by 900%. Levels of cortisol, a stress-response hormone, were decreased slightly.
Another study involved women who saw a 86% increase in norepinephrine and a 510% increase in prolactin after a 20-minute session in a dry sauna twice a week.
In short, sauna bathing can increase norepinephrine and prolactin, two hormones that improve focus and increase speed and efficiency in the brain.
Heat Stress Benefits the Brain
Heat stress and exercise increase brain-derived neurotrophic factor, or BDNF.
BDNF is a protein that promotes the growth of new neurons. It regulates neuroplasticity, or the brain’s ability to adapt and create new connections. BDNF also improves anxiety and depression symptoms from early-life stressful events. It is active in the basal forebrain, hippocampus, cerebellum, and cortex, which are areas connected with learning and long term memory.
As heat stress can increase BDNF, and sauna bathing is a safe, effective form of heat stress, sauna may be a great way to increase BDNF and benefit the brain’s growth and proper functioning.
Sauna and Dementia and Alzheimer’s
Sufficient blood flow to the brain and peripheral nervous system is required for normal cognitive function. Therefore, cognitive decline and cardiovascular problems often go together. For instance, high blood pressure impairs blood flow to the brain by altering the structure of blood vessels in the largest part of the brain (the cerebrum). Poor cerebral blood flow may accelerate the progression of Alzheimer's disease.
What, then, can slow the progression of cognitive diseases such as Alzheimer’s?
Heat stress promotes blood flow, so the findings of one particular study are not surprising: in the Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, an ongoing cohort study of health outcomes in more than 2,300 middle-aged men from Finland, sauna bathing reduced the risk of developing dementia and Alzheimer's disease according to the frequency of sauna use.
Men who used the sauna 4-7 times per week had a 66% lower risk of developing dementia and a 65% lower risk of developing Alzheimer's disease, as opposed to men who used the sauna only one time per week or not at all.
Controlled heat stress helps increase the production of brain-healthy hormones as well as blood flow throughout the body and to the brain. By sauna bathing regularly, you may improve your cardiovascular system as well as decrease your likelihood of developing negative cardiovascular and cognitive effects, such as Alzheimer’s and dementia. Come give it a try with us at PLUNJ!
Gregg C; Shikar V; Larsen P; Mak G; Chojnacki A; Yong VW, et al. (2007). White matter plasticity and enhanced remyelination in the maternal CNS. J Neurosci 27, 8.
Iadecola, Costantino (2004). Neurovascular Regulation In The Normal Brain And In Alzheimer's Disease Nature Reviews Neuroscience 5, 5.
Ishida, Yuko; Tajima, Fumihiro; Kojima, Daisuke; Nakamura, Takeshi; Banno, Motohiko; Umemoto, Yasunori, et al. (2017). Head-out Immersion In Hot Water Increases Serum BDNF In Healthy Males International Journal Of Hyperthermia 34, 6.
Kukkonen-Harjula K; Oja P; Laustiola K; Vuori I; Jolkkonen J; Siitonen S, et al. (1989). Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath. Eur J Appl Physiol Occup Physiol 58, 5.
Patric, Rhonda. (2022). Sauna. Found My Fitness.
Paul Knekt, Ritva Järvinen, Harri Rissanen, Markku Heliövaara, & Arpo Aromaa. (2020). Does sauna bathing protect against dementia? Preventive Medicine Reports, 20(101221-).
Laatikainen, T., Salminen, K., Kohvakka, A. et al. Response of plasma endorphins, prolactin and catecholamines in women to intense heat in a sauna. Europ. J. Appl. Physiol. 57, 98–102 (1988). https://doi.org/10.1007/BF00691246
Laukkanen, Tanjaniina; Kauhanen, Jussi; Laukkanen, Jari Antero; Kunutsor, Setor (2017). Sauna Bathing Is Inversely Associated With Dementia And Alzheimer's Disease In Middle-Aged Finnish Men Age And Ageing 46, 2.
Masuda, Akinori; Nakazato, Masamitsu; Kihara, Takashi; Minagoe, Shinichi; Tei, Chuwa (2005). Repeated Thermal Therapy Diminishes Appetite Loss And Subjective Complaints In Mildly Depressed Patients Psychosomatic Medicine 67, 4.
Salbaum, J.Michael; Cirelli, Chiara; Walcott, Elisabeth; Krushel, Les A.; Edelman, Gerald M.; Tononi, Giulio (2004). Chlorotoxin-mediated Disinhibition Of Noradrenergic Locus Coeruleus Neurons Using A Conditional Transgenic Approach Brain Research 1016, 1.
Rentscher, Kelly; Janssen, Clemens W.; Lowry, Christopher A.; Mehl, Matthias R.; Allen, John J. B.; Kelly, Kimberly L., et al. (2016). Whole-Body Hyperthermia For The Treatment Of Major Depressive Disorder JAMA Psychiatry 73, 8.