HEAT THERAPY
Heat therapy, also known as thermotherapy, has been used for centuries to treat a wide range of ailments and is still widely used today. This form of therapy involves the application of heat to the body to increase circulation, reduce inflammation, and promote relaxation. Heat therapy can be delivered in various ways, including through the use of heating pads, hot water bottles, warm towels, or even hot baths or saunas. Whether you are experiencing muscle soreness, menstrual cramps, or arthritis pain, heat therapy can provide relief and improve overall health.
In this article, we will explore the benefits of heat therapy and how it can be used to improve your wellbeing.
Heat Therapy Benefits
This treatment can be helpful for individuals who suffer from rheumatoid arthritis, muscle stiffness, or injuries to the deep tissue of the skin. It works by increasing collagen tissue extensibility, reduced joint stiffness, pain relief, reduced muscle spasms, and decreased inflammation and edema, aiding in the post-acute phase of healing. Additionally, it can increase blood flow to the affected area, facilitating the delivery of essential nutrients and oxygen to the injured tissue.
Improved blood circulation to the affected area resulting from heat therapy facilitates the delivery of essential nutrients, oxygen, and proteins, which can contribute to better healing outcomes. There is some evidence to suggest that heat therapy can also aid in the treatment of neurodegenerative diseases like Alzheimer’s, as well as for cardiovascular benefits. [1, 2]
Direct Contact Heat
Moist heat therapy is often considered more effective in warming tissues than dry heat due to the faster heat transfer of water compared to air. This method is commonly used to alleviate pain and reduce stiffness in muscles and joints. In addition, regular use of saunas has been associated with a reduced risk of vascular disease. [1, 2, 3, 4, 5]
Infrared Radiation
Infrared radiation (IR) refers to the electromagnetic radiation spectrum ranging from 0.78 μm to 1 mm wavelength. Unlike direct contact heat sources, IR radiation can directly heat the area where the blood capillaries and neuron terminals are located. This is because, with direct contact, the external layer of the skin must first be heated, and the heat is then transferred to deeper layers by conduction.
The IR spectrum is divided into three segments:
- IR-A (0.78 to 1.4 μm),
- IR-B (1.4 to 3 μm), and
- IR-C (3 μm to 1 mm).
IR radiation is more effective than visible radiation for heating the body, as it is mostly absorbed rather than being strongly reflected. The depth of penetration of IR radiation into the skin varies with wavelength, with IR-A being the most penetrating, reaching several millimeters, IR-B penetrating into the dermis (about 1 mm), and IR-C being mostly absorbed in the external layer of the epidermis (stratum corneum). As a result, infrared lamps used for therapeutic purposes mainly produce IR-A radiation.
Mechanism of Action & Indications
The application of heat increases tissue temperatures, resulting in vasodilation that enhances the supply of oxygen and nutrients while eliminating carbon dioxide and metabolic waste from the affected area. Heat therapy is beneficial for a variety of conditions, including muscle spasms, myalgia, fibromyalgia, contracture, and bursitis.
The application of moist heat to abscesses can facilitate faster drainage of the affected area.
Heat therapy has demonstrated efficacy in the treatment of leishmaniasis, a parasitic skin infection prevalent in tropical regions.
The use of heat therapy is **not recommended** in cases of acute injury and bleeding disorders due to the vasodilation effect, as well as in tissues with severe lack of sensitivity, scars, and areas with inadequate vascular supply. In tissues with poor blood supply, the increased metabolic rate and demand induced by heat therapy may lead to ischemia and compromise healing outcomes.
Contrast Bath Therapy
Contrast bath therapy involves alternating between cold and warm water immersion. This process is repeated multiple times, alternating between hot and cold temperatures.
The hot water causes vasodilation and the cold water causes vasoconstriction. Alternating between vasoconstriction and vasodilation, enhancing blood flow, reducing inflammation, and improving range of motion are some of the ways that it is believed to help facilitate recovery.
This alternation is thought to increase local blood circulation and stimulate the lymph vessels to contract and relax, effectively “pumping” stagnant fluid out of the injured area. The lymph system lacks a central pump, and alternating hot and cold is believed to aid the inflammation process, which is crucial for healing damaged tissue.
Contrast baths are not recommended during the acute inflammation stage for injuries that exhibit palpable swelling and heat, as well as visible redness, such as strains or sprains. This stage of acute inflammation typically lasts for around 72 hours after the injury.
Sauna for Recovery & Health
Saunas come in various types, all designed as rooms heated within the range of 150°F to 195°F (65°C to 90°C). The Finnish-style saunas are often regarded as “dry,” whereas Turkish-style saunas embrace high steam levels. Typically, individuals spend about 15 to 30 minutes inside a sauna, adjusting based on their heat tolerance. Differences between saunas primarily arise from their heat generation methods. The commonly recognized types include:
- Wood Burning: Using wood-burning stoves to heat sauna rocks, these saunas maintain high temperatures with relatively lower humidity levels.
- Electrically Heated Sauna: Utilizing an electric heater fixed on the floor or wall, these saunas reach high temperatures while also keeping humidity levels relatively low.
- Steam Rooms: Also known as “Turkish bath houses,” these saunas maintain lower temperatures but have extremely high humidity, reaching 100 percent.
- Infrared Saunas: Equipped with specialized lamps emitting light waves, these saunas heat your body directly without significantly warming the sauna room. They offer similar benefits to conventional saunas but at much lower temperatures, typically around 140°F (60°C).
Although sauna temperatures and humidity levels vary among these types, their impact on the body remains similar across the board.
Sauna sessions have shown considerable benefits for longevity and heart health. Spending time in the sauna four to seven times per week has been associated with reduced risks of sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease, and all-cause mortality.
Additionally, saunas exhibit potential improvements in endurance and aerobic capacity. Regular sauna bathing can significantly enhance time to exhaustion and increase plasma and red blood cell volumes, which may contribute to better performance by elevating blood volume. Sauna exposure is also believed to aid in developing tolerance to heat, potentially assisting individuals in coping with the body’s natural temperature rise during prolonged physical exertion.
Sauna therapy also appears to stimulate muscle growth and recovery. It has been linked to an increase in the production of “heat shock proteins,” which play a role in repairing damaged proteins in the body and protecting against oxidative damage, potentially aiding in muscle recovery and growth. Additionally, sauna exposure has shown an increase in growth hormone levels and improved insulin sensitivity, both contributing factors to muscle maintenance and growth.
Furthermore, sauna usage has been associated with cognitive benefits. Spending time in the sauna leads to the release of norepinephrine, believed to have protective effects against conditions like Alzheimer’s and migraines. The exposure to heat also elevates brain-derived neurotrophic factor (BDNF), linked to increased cognitive function and the generation of new neurons.
Sauna bathing has been found to contribute to skin health by aiding in skin self-cleansing and the removal of dead skin cells, promoting healthier and better-protected skin.
Moreover, sauna usage post-workout has been shown to potentially boost the immune system, via the increase in white blood cells after a short sauna session, potentially enhancing aerobic capacity, speed, agility, and lower-body power.
Sauna sessions also induce changes in hormone secretion, including increased growth hormone and prolactin levels, the release of norepinephrine, and changes in cortisol secretion. However, the effects on cortisol secretion remain somewhat contradictory.
Intermittent post-exercise sauna bathing in trained middle-distance runners demonstrated improvements in exercise capacity in both hot and temperate conditions. A case study involving the world’s top junior female tennis player showed that three weeks of post-training sauna bathing resulted in enhanced aerobic capacity, speed, and anaerobic threshold without any adverse effects on performance. Another study revealed that post-exercise infrared sauna sessions improved neuromuscular performance and reduced muscle soreness after resistance exercise training.
Lastly, a study investigating the effects of hyperthermic whole-body heat stimulus on skeletal muscle hypertrophy during resistance training found that sauna use, when combined with resistance training, did not significantly enhance muscle hypertrophy or strength. The research concluded that although sauna bathing stimulated changes in hormone secretion (such as increased growth hormone and prolactin levels), the effects on muscle hypertrophy and strength were not pronounced and varied among groups
Optimizing Recovery with Heat Therapy
As a coach, I highly advocate for the use of heat therapy as an effective means to support faster recovery between workouts and reduce post-exercise soreness among my clients and athletes. Heat therapy, including methods like direct contact heat, infrared radiation, and sauna, has demonstrated remarkable benefits in alleviating various conditions such as muscle stiffness, joint pain, and aiding in the healing process of deep tissue injuries. Its ability to increase blood circulation, promote tissue repair, and reduce inflammation makes it an invaluable tool in optimizing recovery.
Summary
Tldr; Heat therapy, spanning direct contact heat, infrared radiation, and heating pads or saunas, aids in alleviating muscle stiffness, joint pain, and supports deep tissue healing.
Application of heat boosts circulation, accelerates nutrient and oxygen delivery, aiding in tissue repair and reducing inflammation.
Heat therapy can assist in conditions like rheumatoid arthritis and muscle injuries.
Heat therapy improves blood flow, delivering nutrients and oxygen, potentially aiding in Alzheimer’s treatment and offering cardiovascular benefits.
Moist heat proves effective in warming tissues, while infrared radiation penetrates deeply into the skin for therapeutic benefits.
Vasodilation induced by heat enhances oxygen supply, nutrient delivery, and waste removal, aiding recovery.
Contrast bath therapy alternates between hot and cold immersion, bolstering blood flow and reducing inflammation.
Alternating temperatures in contrast baths assists in lymph vessel stimulation, crucial for healing damaged tissue.
Frequent sauna use is linked to reduced risks of heart diseases and mortality.
Saunas potentially enhance endurance, aid muscle recovery, stimulate growth hormones, and boost cognitive functions.
Sauna contributes to skin health, immunity, and hormone secretion but show contradictory effects on cortisol.
Post-exercise sauna use demonstrates improved performance, reduced soreness, and increased aerobic capacity in athletes.
However, while sauna exposure stimulates hormone changes, its direct impact on muscle hypertrophy remains inconclusive.
Heat therapy isn’t recommended during acute injury, bleeding disorders, or in tissues with inadequate vascular supply.
Regular use of heat therapy can enhance overall wellbeing by promoting faster recovery and reducing soreness.
