Could Heat Therapy Be an Effective Treatment for Alzheimer’s and Parkinson’s Diseases? A Narrative Review

Abstract

Neurodegenerative diseases involve the progressive deterioration of structures within the central nervous system responsible for motor control, cognition, and autonomic function. Alzheimer's disease and Parkinson's disease are among the most common neurodegenerative disease and have an increasing prevalence over the age of 50. Central in the pathophysiology of these neurodegenerative diseases is the loss of protein homeostasis, resulting in misfolding and aggregation of damaged proteins. An element of the protein homeostasis network that prevents the dysregulation associated with neurodegeneration is the role of molecular chaperones. Heat shock proteins (HSPs) are chaperones that regulate the aggregation and disaggregation of proteins in intracellular and extracellular spaces, and evidence supports their protective effect against protein aggregation common to neurodegenerative diseases. Consequently, upregulation of HSPs, such as HSP70, may be a target for therapeutic intervention for protection against neurodegeneration. A novel therapeutic intervention to increase the expression of HSP may be found in heat therapy and/or heat acclimation. In healthy populations, these interventions have been shown to increase HSP expression. Elevated HSP may have central therapeutic effects, preventing or reducing the toxicity of protein aggregation, and/or peripherally by enhancing neuromuscular function. Broader physiological responses to heat therapy have also been identified and include improvements in muscle function, cerebral blood flow, and markers of metabolic health. These outcomes may also have a significant benefit for people with neurodegenerative disease. While there is limited research into body warming in patient populations, regular passive heating (sauna bathing) has been associated with a reduced risk of developing neurodegenerative disease. Therefore, the emerging evidence is compelling and warrants further investigation of the potential benefits of heat acclimation and passive heat therapy for sufferers of neurodegenerative diseases.

Does sauna bathing protect against dementia?

“…Passive body heating elicits several physiological, metabolic, and cellular changes which may affect brain function. The importance of these mechanisms in the dementia development however remains to be ascertained ( Hunt et al, 2020 ).…”

“…Heat shock proteins are important regulators in normal cell functions and have an essential role in guarding and controlling protein formation ( Schlesinger, 1990 , Stetler et al, 2010 ). Because disturbances of protein construction and folding are central to the development of neurological diseases, heat shock proteins may be important in maintaining protein homeostasis in the brain ( Kampinga and Bergink, 2016 , Hunt et al, 2020 ).…”

“…The potential benefits of passive body heating in the brain have aroused interest recently ( Coombs and Tremblay, 2019 , Hunt et al, 2020 ). In Finland sauna bathing is an old tradition, and it represents one type/method of passive body heating.…”

Are Heat Shock Proteins an Important Link between Type 2 Diabetes and Alzheimer Disease?

“…Matrine has also shown an ability to reduce the pro-inflammatory actions of microglia in the brain, potentially affecting the progression of AD [147,169]. Other methods of HSR induction, such as heat therapy, exercise, and mild electrical stimulation, have also shown therapeutic potential in the treatments of T2D and AD [167,[170][171][172]. Despite the body of evidence available demonstrating the role of HSPs as therapeutic targets in T2D and AD, this is still an area with large potential to explore.…”

A Review of Heat Therapy in African Traditional Medicine

“…Heat therapy has been used extensively for treating several diseases such as: sickle cell disease [17], primary dysmenorrhea [18], skeletomuscular pain, trauma, inflammatory and degenerative rheumatic diseases [19], and osteoarthritis [4]. Others include: acute and non-specific chronic low back pain [2,8,20], fibromyalgia [7], cutaneous leishmaniasis [21,22], tumours [13], musculoskeletal injuries [5,23], Alzheimer's and Parkinson's diseases [24], diabetic kidney disease [25], etc. Therapeutic effects of heat include: increased muscle flexibility of the lower back [26], increasing the extensibility of collagen tissues, decreasing joint stiffness reducing pain, relieving muscle spasm, reducing inflammation and edema aids in the post-acute phase of healing, and increasing blood circulation.…”