The Healing Effect of Mud Pillows in Heat Therapy

Die heilsame Wirkung von Moorkissen in der Wärmetherapie

A person relaxes with a mud pillow on their back - a classic example of heat therapy as practiced in physiotherapy practices. © Copyright Vakker Products GmbH

As early as the 19th century, people valued the positive effects of natural moor on their health. By taking mud baths, rubbing themselves with it or even drinking it, they were able to initiate healing processes and increase their general well-being. But how and why does it work so well?

How heat therapy works

Heat therapy refers to the external application of heat with the aim of loosening the tissue, relieving tension and muscle stiffness and relaxing us. The metabolism is stimulated, which accelerates healing processes, for example in the case of sore muscles. Sounds great, but what are these effects based on?

Human with a body temperature of 37 degrees

37° C — this is the approximate temperature that the body tries to maintain through various regulatory mechanisms. © Copyright Vakker Products GmbH

Effect through the body's own temperature regulation mechanisms

In order to function optimally and, above all, to survive, our body is constantly busy regulating its own temperature to 37°C plus minus 0.5°C. Depending on the outside temperature, it uses different mechanisms:

The effects of heat on the body

  • Our bloodstreams dilate to direct more blood to the external areas. This protects us from overheating of the internal organs that are vital to survival, which could be fatal due to denatured proteins.

  • Blood pressure drops because there is now more space for the same amount of blood. This also means that our parasympathetic nervous system switches on, allowing us to enter a state of relaxation and regeneration.

  • Muscular and fascial structures become softer and loosen up because, on the one hand, the lowered blood pressure suggests a danger-free situation and so tense muscles are not necessary for survival. On the other hand, there is now enough outside heat, which means our body does not have to produce additional heat through tense muscles.

The effects of cold on the body

  • Our blood vessels constrict in order to supply our internal organs with sufficient heat and thus prevent a slowdown or failure of important metabolic processes.

  • Blood pressure and pulse increase because more strength is now required to direct the blood through the narrowed pathways. Among other things, this activates the sympathetic nervous system, which puts us in a state of stress.

  • Our muscles tense, on the one hand to produce heat and on the other hand because the sympathetic nervous system has put us in stress mode; we finally have to be ready for the fight with the saber-toothed tiger (or perhaps rather the escape from the latter). By the way, the typical trembling is another level of muscle tension, an attempt by our body to produce heat.

The positive side effects of expanded blood vessels

If our heat-sensitive nerve cells, which are located in the skin, spine and brain, perceive the outside temperature to be too warm, they report this condition directly to the hypothalamus. If the temperature limit is exceeded, this gives the starting signal for the release of hormones, which then set various regulatory processes in motion. The dilation of blood vessels is one of them. And this mechanism is not only useful for temperature regulation, we also benefit from another extremely pleasant consequence of the expanded blood vessels.

dilated blood vessels

Dilated blood vessels enable accelerated metabolism. Nutrients are transported into the cells more quickly and waste products can be eliminated more quickly, which means that the tissue regenerates more quickly. © Copyright Vakker Products GmbH

Metabolic processes and thus the healing of tense, hardened tissue are accelerated

Nutrients can be transported more quickly to the tissue to be repaired and at the same time metabolic waste products are removed more quickly. This is also the reason why a sauna or hot bath can significantly relieve muscle soreness or even prevent it entirely.

What makes natural moor the most effective heat carrier in heat therapy

A bog forms where there is sufficient vegetation, moisture and a mild climate. The dark mass, also called "peat", is created by the slow decomposition of mosses, grasses and all kinds of plant remains. It is, so to speak, the transition level between land and water. As such, it is packed and highly concentrated with botanicals and has two particular "superpowers".

The exceptional heat capacity and conductivity of natural moor

In principle, heat capacity means nothing more than "heat storage capacity", but it is of great importance for the effectiveness of heat treatment. The longer the application, the more deeply tension can be relieved.

To give you a feel for how different materials differ in terms of these physical properties, we have created a small comparison table for you below. But first let’s clarify the two relevant measurements for effective heat therapy.


Heat capacity, also called specific heat capacity in physics, indicates the amount of energy that is necessary to heat a unit of mass (e.g. grams (g)) by a unit of temperature (e.g. Celsius (°C). The most common units of measurement resulting from this are for example "J (energy) / kg (mass)" or "cal (energy) / g (mass)". In our table we use the unit "cal / g".


Thermal conductivity or thermal conductivity (λ) indicates the speed at which heat spreads within a material. It is independent of temperature and is calculated using the following formula:

W / (m*K) → Watt / (meter * Kelvin)

Watt is the energy expenditure per hour and Kelvin is the commonly used unit of "thermodynamic temperature".

Heat capacity (cal/g/°C)
Thermal conductivity (W/(m*K))
connective tissue
1.00 - 2.00 (depending on humidity)
0.09 - 0.12
0.28 - 0.4
0.13 - 0.18

What do heat capacity and thermal conductivity have to do with the effectiveness of heat therapy?

Once you understand the principle, it's actually pretty obvious. The underlying phenomenon is that substances with the same temperature but different thermal conductivity are perceived as having different temperatures. To do this, imagine yourself touching a 90°C hot piece of steel (the meaningfulness of which remains an open question here). This idea probably causes pain and burns.

Man on hot steel

If you touch steel, whose thermal conductivity rate is high, you will find the 90° C to be unbearably hot. © Copyright Vakker Products GmbH

Now imagine yourself in a Finnish sauna. You are the hard-core type and choose the 90°C hot sauna. If you touch the wood here, the wood at 90°C, you can tolerate it much better. The pain and burn blisters also disappear. And this despite the fact that it is exactly the same temperature. Why is that so?

Man on hot wood

Wood, on the other hand, has a lower thermal conductivity velocity. The same temperature is perceived as more pleasant because the conduction speed is similar to that of human tissue and there is no build-up of heat. © Copyright Vakker Products GmbH


As you can see in the table above, wood has a significantly lower thermal conductivity than steel. It is also relatively close to the thermal conductivity of human body tissue. The thermal conductivity index primarily indicates the speed of temperature transfer and with steel this is simply too fast for our somewhat more comfortable fabric. The extremely rapid heat that comes from the steel cannot be transported any further, but it also cannot simply disappear. What happens? A heat build-up occurs and the heat concentrates on the surface.

So the temperature of materials with a thermal conductivity close to that of human tissue is not only perceived as less hot because there is no heat build-up, but overall more heat is transported into the body because the heat has not already dissipated in the form of a heat build-up. Because the temperature is perceived as less hot, materials with lower thermal conductivity can be applied at higher temperatures. And higher temperature comes with two cumulative, positive consequences:

  • A higher temperature enables a longer application period with the therapeutically effective temperature of over 40° C.

  • A higher temperature reaches deeper layers of tissue and can therefore loosen even deep-seated hardenings.

What does a mud pillow do in heat therapy? - A summary

Thanks to the body's own temperature regulation mechanisms, we can use external heat to expand our blood vessels, which promotes healing and regeneration processes through the now accelerated metabolism. Hardened muscles and tensions are released. In addition, our blood pressure drops, which activates our parasympathetic nervous system and puts the entire body into relaxation and repair mode.

Thanks to the thermal conductivity of natural moor, which is comparable to the human body, moor cushions can be applied at a higher temperature, thereby reaching deeper tissue layers. The associated high heat storage capacity also ensures particularly long use.