Therapeutic heat (local thermotherapy) is one of the best-documented analgesic methods in physical medicine. Its effectiveness is based on three simultaneous physiological mechanisms. Local vasodilation increases oxygen supply to injured tissues and facilitates the removal of metabolic waste products (lactate, pro-inflammatory bradykinin). Muscle relaxation lowers the trigger threshold of neuromuscular spindles, reducing muscle tone and alleviating contractures and spasms. Central analgesia: the activation of cutaneous TRPV1 thermoreceptors by heat competitively inhibits the transmission of pain signals via C and Aδ fibers — an effect known as “counter-irritation,” which explains the immediate reduction in pain when applying a hot water bottle.
The choice of heat pad depends on the target area and the type of heat desired. Microbead pads (Actipoche Cervical & Trapezius 24×40 cm, Actipoche Targeted Areas 10×20 cm) can be heated in the microwave and provide gentle, moist heat for 20–30 minutes—effective for deep muscle tension (neck, trapezius, lower back). Natural rubber hot water bottles (Cooper Blue) provide prolonged, adjustable dry heat. The electric heating vest with a temperature control is designed to target chronic back pain through long-term use. The rapeseed-filled heating pillows combine a soft feel with gentle, diffused heat—particularly suitable for children and people with sensitive skin.
Painful periods (primary dysmenorrhea) result from excessive production of uterine prostaglandins (PGF2α and PGE2), which cause intense, ischemic contractions. Local heat (Dysmecalm heating patch, hot water bottle on the lower abdomen at 40°C) has a dual effect: uterine vasodilation, which reduces ischemia of the myometrium, and activation of TRPV1 receptors, which inhibits nociceptive transmission. Randomized studies confirm that the efficacy of local heat (40°C, 8 hours per 24-hour period) is comparable to that of 400 mg of ibuprofen for mild to moderate primary dysmenorrhea. Alchemilla fluid extract (a traditional uterotonic herb) complements this approach by regulating the menstrual cycle.
Heat is one of the few interventions with solid clinical validation for acute nonspecific lower back pain —heating pads for the lower back relieve muscle spasms in the paravertebral muscles responsible for the pain. Moist heat (microbeads) penetrates deeper into the tissues than dry heat and is preferable for deep muscle pain. For nighttime or exercise-induced muscle cramps, preventive heat therapy (before bedtime) reduces neuromuscular excitability and prevents recurrent episodes in the lower limbs. Airplus Aloe socks (Cabin and Spa) improve circulation in the extremities, reducing vascular tension that contributes to nighttime cramps.
Thermotherapy is not universally applicable. It is contraindicated within the first 48 hours following an acute injury (sprain, contusion, hematoma), on active acute inflammation (warm, red swelling), on areas of skin anesthesia, and in cases of fever. The PRICE rule (Protection, Rest, Ice, Compression, Elevation) applies to acute injuries—ice reduces inflammation and swelling within the first 48 hours, after which heat takes over during the subacute phase to relax tight muscles. For hot flashes associated with menopause, external heat should be avoided—Airplus socks are intended for cold extremities, not for vasomotor episodes.
The effectiveness of thermotherapy depends heavily on the temperature and duration of application. The optimal therapeutic range is between 38°C and 42°C—below this, the analgesic effect is insufficient; above 45°C, the risk of skin burns increases significantly. The recommended duration is 15 to 30 minutes per session, repeatable 3 to 4 times a day for acute pain. Moist heat (microbeads or steam) penetrates up to 3–4 cm deep into the tissues, compared to 1–2 cm for dry heat—a decisive advantage for deep muscle and joint pain. Placing a layer of fabric (such as a thin towel) between the device and the skin is recommended for those with sensitive skin, children, and the elderly to prevent the risk of burns during prolonged use.
