Is there any scientific basis for the claim that hot water or saunas can help remove ticks or destroy pathogens?
Diseases spread by ticks – especially Lyme disease – are becoming an increasingly serious public health problem worldwide, including in Hungary. Lyme disease is caused by Borrelia bacteria, which are spread by ticks and can enter the human body through a bite. The infection can be treated effectively with antibiotics in its early stages, but if it is detected late, it can lead to serious complications.
In recent years, more and more research has been conducted into how ticks and the pathogens they carry behave in response to various environmental influences. Temperature, especially heat (e.g. saunas or hot baths), may play an interesting role in prevention. But is there any scientific basis for the idea that hot water or saunas can help remove ticks or destroy pathogens?
Heat tolerance and reproduction of the bacterium
Members of the Borrelia burgdorferi sensu lato group, which causes Lyme disease, are widespread throughout the world. The clinical course of the disease and which animal species are capable of maintaining the infection in the long term depend in part on the temperatures at which individual Borrelia strains can survive and reproduce. A recent experimental study compared the temperature tolerance and growth characteristics of three different Borrelia strains — B. burgdorferi, B. garinii and B. afzelii — and drew a number of interesting conclusions.
Temperature profiles of the three Borrelia strains
According to the study, all of the Borrelia strains examined were able to reproduce between 28 and 37 °C, but their growth dynamics and heat tolerance differed significantly.
Optimal and maximum growth temperatures:
B. burgdorferi s.s.: Optimal growth at 33°C, maximum at 39°C.
B. afzelii: Optimal 33–37 °C, maximum 40 °C.
B. garinii: Optimal 37 °C, maximum 41 °C.
Based on this, B. garinii proved to be the most heat-tolerant strain, while B. burgdorferi s.s. was the most sensitive to higher temperatures. At 41°C, only the Borrelia garinii strain showed any activity — after 8 days, 63% were still moving, while after 16 days this proportion had fallen to 1%. In contrast, B. burgdorferi s.s. did not reproduce above 39 °C, and at 42 °C, neither strain showed growth or viability after 4 days.
Survivability at low temperatures
During long-term incubation at 20°C:
B. burgdorferi s.s. was completely destroyed after 81 days.
B. garinii showed significant cell growth (6.3 × 10⁷ cells/ml) with 98% motility.
B. afzelii also remained viable (3.7 × 10⁷ cells/ml, 74% motility).
This indicates that some Borrelia strains are able to survive not only in temperatures close to body temperature, but also in colder environments, which is important from an ecological and epidemiological point of view.
What does this mean for Lyme disease?
Differences in heat tolerance and reproduction also influence the clinical form caused by each strain:
B. afzelii is typically associated with skin symptoms (e.g. erythema migrans) and joint symptoms.
B. garinii more often causes neurological symptoms, such as meningoradiculoneuritis.
The heat tolerance of B. garinii may explain why it is able to colonise birds, whose rectal temperature often exceeds 41 °C. In contrast, B. burgdorferi s.s. is unlikely to survive for long periods in birds, so small mammals are its main hosts.
Saunas and hot baths: are they effective against Lyme disease?
Saunas or hot baths as a form of home treatment are recommended in many naturopathic approaches, mainly because of the heat sensitivity of pathogens. However, based on the present study, it is clear that certain strains of Borrelia bacteria can remain viable at temperatures of 40–41 °C and can even reproduce, albeit to a limited extent.
The typical temperature of a sauna (80–100 °C) exceeds the viability limits of Borrelia, but even during a sauna session, the core temperature of the human body does not rise permanently above 40 °C, as heat regulation protects the organs from damage. Thus, it is unlikely that bacteria can be effectively “eradicated” from the body by simply using a sauna. However, it can play a supportive, complementary role, for example by stimulating the immune response or increasing circulation, and toxins can also be eliminated from the body by stimulating perspiration.
Hot baths and joint problems: Balneotherapy to relieve the symptoms of rheumatoid arthritis
Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease that causes persistent joint inflammation, pain and, over time, joint damage and limited mobility. Although the exact cause of the disease remains unknown, there is growing evidence that certain infections, such as Borrelia burgdorferi, the bacterium that causes Lyme disease, may play a role in triggering autoimmune reactions, for example through molecular mimicry. This can result in chronic joint inflammation that is clinically similar to RA or even trigger its manifestation in genetically susceptible individuals.
Balneotherapy, or spa treatment, uses natural mineral waters such as sulphurous, radon and carbonated waters for therapeutic purposes. A literature review analysed eight randomised controlled trials (RCTs) published between 1980 and 2014, involving a total of 496 RA patients. The results of the studies showed that, although the methodology of the studies and the therapies used differed, there was a significant improvement in several clinical parameters after balneotherapy.
The most commonly observed beneficial effects were:
Reduction in morning joint stiffness
Decrease in the number of inflamed joints
Improvement in functional capacity for up to 6 months
Increased hand grip strength
Improved ability to perform everyday activities.
The study did not produce any clear significant results in terms of pain perception (VAS scale). The researchers emphasise that the unique chemical composition of different mineral waters and the clinical diversity of patients make it difficult to draw uniform conclusions. However, balneotherapy is non-invasive, has no side effects and may be a promising complementary treatment for RA, especially during active inflammatory phases.
It is important to note that Borrelia afzelii is one of the most common species causing Lyme disease in Europe. It primarily causes skin and joint manifestations. Several studies have indicated that B. afzelii is more heat-sensitive than other Borrelia species and that heat exposure can reduce its viability under laboratory conditions.
Although there is currently no direct clinical evidence that hot baths or balneotherapy directly “destroy” Borrelia afzelii in the human body, heat increases local blood circulation and immune response, which may promote the removal of pathogens and the alleviation of joint inflammation. In addition, the anti-inflammatory and analgesic effects of balneotherapy are well documented in rheumatic diseases, so it may even indirectly contribute to the alleviation of Lyme arthritis symptoms.
Tick behaviour in warm water – what happens during bathing?
Recent research also looks at the effect of warm water, such as a hot bath, on ticks themselves. According to a recent study, warm or soapy water can actually wash unattached ticks (i.e. ticks crawling on the skin but not yet attached) off the skin, especially if the person undresses before bathing or showering, making it easier to spot the parasite.
In the study, various tick species – including Ixodes scapularis, the main carrier of Lyme disease – were exposed to water at 40–45°C. They observed that the behaviour of the ticks differed depending on the surface they were on (e.g. silicone or pigskin) and whether the water contained soap. The results showed that:
Younger, smaller ticks lost contact with the surface more often in warm water, especially on silicone surfaces.
Some adult ticks lost their mobility in warm, soapy water and sometimes did not recover.
This suggests that warm bathing (above 40°C), especially in soapy water, can actually reduce the chance of an undetected tick becoming permanently attached to the skin. This is particularly important because many infections are caused by smaller, younger ticks, which are difficult to spot.
The role of bathing and saunas in prevention
Saunas do not “cure” Lyme disease, but they can help with prevention in several ways:
Facilitating self-examination: undressing and warm water can help you spot ticks.
Removing unattached ticks: warm, soapy water can loosen ticks crawling on the skin.
Physiological effects: heat can boost immune function, and (in theory) some pathogens may be sensitive to heat.
However, it is important to note that water will not remove ticks that are already attached; only physical removal (with tweezers or a tick removal spoon) is suitable for this purpose.
Summary
Heat, whether in the form of a sauna or a hot bath, is not a miracle cure for Lyme disease, but it can contribute to prevention in a scientifically proven way. Warm, soapy water can remove ticks crawling on the skin, especially if they have not yet attached themselves. Although a sauna does not completely destroy pathogens in the body, it can reduce their numbers, support the immune system and improve overall regeneration.
However, the most important thing remains regular self-checking and removing ticks as soon as possible.
Sources:
https://pubmed.ncbi.nlm.nih.gov/9788818/
https://pubmed.ncbi.nlm.nih.gov/34919573/
https://pubmed.ncbi.nlm.nih.gov/26607275/
https://pubmed.ncbi.nlm.nih.gov/29730741/
(C) Lyme Borreliosis Foundation
