This blog will explore different types of heat therapy with a focus on heat therapy for lymphedema. I undertook this investigation to answer some common questions like; Is heat good for lymphedema? Does heat make lymphedema worse? Does heat help lymphedema?
Keep in mind, this information does not replace the experience and recommendations of your health care professional.
Heat Therapy
Heat therapy also called thermotherapy or hyperthermia (hyper=high and thermia = generation of heat). It can be administered via sauna in several forms including; infrared sauna, steam baths, and Finnish saunas. When it comes to overall health and sauna therapy, the most widely studied modality is the traditional Finnish sauna (Laukkanen, 2018).
There are also non-sauna versions of heat therapy such as ultrasound, electromagnetic therapy, microwave therapy, hot tubs and heating pads. These have all been studied in lymphedema (keep reading for that information). But first, let’s answer the question…what are these different types of heat therapy?
Types of Heat Therapy
Hot Tubs
Also known as whirlpools, and Jacuzzi’s these are large tubs in which treated water circulates through a filtration system and through jets. They have a thermostat for you to regulate the temperature of the water, the body can heat up quickly in a hot tub as they can be fully immersed in the hot water.
Electromagnetic Therapy
Pulsed electromagnetic field therapy (PEMF therapy) or low field magnetic stimulation (LFMS) uses electromagnetic fields to heal fractures and to treat depression. They look like thick yoga mats and they contain flat spiral coils to transmit an even electromagnetic field.
Finnish Sauna
Dry air heated to 150-195F (80-100C) within a wooden structure with wood benches with 10-20% humidity usually for 5 to 20 minutes with cooling off periods in between. Thy are very popular in their namesake country Finland.
Infrared Sauna
Also called far infrared saunas, which refers to the far end of the light spectrum. Rather than heating your body by heating the air, the infrared sauna, heats your body through infrared light. The infrared sauna does not heat up to the same temperature and can be more comfortable for people. The temperature inside an infrared sauna is typically 110-135F (43-57C).
Microwave Therapy
Before, you think it…no, this does not involve giant microwave ovens. It does involve very high frequency electromagnetic waves that can penetrate 3-5 cm below the skin. It generates heat which can be directed towards a specific target area by using a hand held device.
Steam Bath
Also called Turkish baths, steam rooms were traditionally used as public bath houses before indoor plumbing. The temperature is 100-110F (38-43C), with very high humidity (Human Kenetics, 2023).
Ozone Sauna
This is an individual-sized steam chamber supplied with ozone from an ozone generator. The user would sit in the chamber with their head outside. It should be noted that ozone saunas do not have a medical device license from Health Canada, which means they have not been approved for use and Health Canada recommends that you do not use them (Health Canada, 2022). Health Canada notes on their website that exposure to excessive levels of ozone may cause headache, cough, dry throat, nausea, shortness of breath and fluid buildup in the lungs (pulmonary edema).
Ultrasound Therapy
We often think of ultrasound as a diagnostic tool that is used to see inside the body and any pregnant woman has likely had several ultrasounds of their growing fetus during which you can see a grainy image of the baby. Ultrasound is also used as a treatment device by physical therapists for pain, injury and muscle spasms. These can be thermal or mechanical devices. The thermal devices work by causing the skin and muscles to vibrate and heat up, transferring heat through the skin to the organs and tissues under the skin.
Sauna Therapy and Overall Health
A 2018 review published by researchers from Finland examined the health effects of saunas (Laukkanen, 2018). The use of saunas is very popular in Finland where they are used for pleasure, wellness and relaxation. Some of the health benefits associated with sauna use include:
• Reduction of high blood pressure
• Reduction of cardiovascular disease risk
• Reduction of stroke risk
• Reduction in cognitive disease risk
• Reduction of flu risk
• Reduced mortality
• Treatment of skin conditions
• Reduced pain due to rheumatic disease
• Reduced headaches
• Reduced oxidative stress and inflammation
• Improved blood cholesterol levels
During sauna, the heart rate increases to about 120-150 beats per minute. Blood is diverted from the internal organs to the arms and legs with reduced venous return. With all of these health benefits, it’s easy to see why someone with lymphedema might want to partake. But is sauna safe for lymphedema?
Heat Therapy and Lymphedema
The current position paper on Risk Reduction from the National Lymphedema Network states “avoid exposure to extreme heat and cold”. This was last updated in 2012 and the organization has plans to update all of their position papers (NLN, 2012).
Let’s look at some recent research to see if these recommendations may need to change. Thankfully, there is a brand new review paper published that examines this exact question (Hill, 2023).
This authors summarize the research included in their review as follows:
• 18 studies
• Published between 1986 and 2022
• Research studies took place in China (7), Italy (4), Japan (3), India (2), Brazil (1), Egypt (1) and USA (1)
• A total of 1,137 people with lymphedema were included in the review
Within this collection of studies, heat therapy was applied using:
• Microwave therapy
• Microwave plus bandaging (with or without vibration)
• Hot water
• Light therapy (with and without inferential therapy with or without compression)
• Infrared sauna
• Electric blanket plus manual lymphatic drainage
• Ultrasound
• Electromagnetic therapy
With the heat application, most studies were aiming to achieve skin temperature of 30-42F.
Findings of Heat Therapy for Lymphedema Review
Overall, these studies found benefit for lymphedema after heat therapy. But before you start getting in a sauna with your lymphedema, you need to carefully evaluate the type of heat therapy, the temperature and duration used in these studies, and discuss it with your lymphedema therapist before you proceed.
I’ve summarized the results below in this table to help you determine what further research you need to do.
*this is a summary only. For more details, look up the individual studies – see reference section below.
Conclusions on Heat Therapy for Lymphedema
While this was an excellent effort to collect and assimilate all of the research on heat therapy for lymphedema, in the end, the authors concluded that they still don’t have enough research to make any recommendations on heat therapy for lymphedema. But…they point out that there is enough evidence to suggest further research is warranted.
One thing I’ll mention is that, even though this research review is new (published in 2023), several of the studies that they have included are not. I echo the authors position that more research is warranted, especially now that we have newer ways of evaluating lymphedema – this can help determine if heat is harmful, or if it really is beneficial and if it is beneficial, with which treatments, which lymphedema types and stages, for how long and what temperature.
I checked ClinicalTrials.gov to see if any research is currently underway on heat and lymphedema and there are not any studies currently listed. But if you want to check for updates yourself, go to ClinicalTrials.gov
Should you use heat with your lymphedema?
Discuss it with your lymphedema therapist, share the experiences you’ve had with heat exposure with your lymphedema to date and you can share this blog with your health care professional if they want convenient access to the research that’s been published so far.
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References on Heat Therapy for Lymphedema
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Campisi C, Boccardo F, Tacchella M. Use of thermotherapy in management of lymphedema: clinical observations. Int J Angiol. 1999;8(1):73–75. doi: 10.1007/BF01616849.
Campisi C, Boccardo F, Tacchella M. Thermotherapy and microsurgery: new trends in the management of lymphedema.Eur J Lymphol Relat Prob. 1995;5(17–18):23–25.
Cao W, Chang T, Gan J. Effects of microwave heating on systemic and local infiltrating lymphocytes in patients with chronic limb lymphedema. Chin Med J. 1999;112(9):822–827.
Chang TS, Gan JL, Fu KD, et al. The use of 5,6 benzo-[alpha]-pyrone (coumarin) and heating by microwaves in the treatment of chronic lymphedema of the legs. Lymphology.1996;29(3):106–111.
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Health Canada. Unlicensed ozone saunas may pose serious health risks to users and anyone in close proximity. Last updated Nov 2, 2022. Accessed Dec 1, 2023
Hill, J. E., Whitaker, J. C., Sharafi, N., Hamer, O., Chohan, A., Harris, C., & Clegg, A. (2023). The effectiveness and safety of heat/cold therapy in adults with lymphoedema: systematic review. Disability and rehabilitation, 1–12. Advance online publication.
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