Authors : Betânia Ferreira and Cláudio Ferreira LUZ 24 Applying cold or heat to the body surface to relieve pain and inflammation due to injuries is very common and very useful. However, applying one or the other is not the same . Cold and heat have their own mechanism of action and, therefore, specific indications and contraindications, which are related to the situation and also to the particularities of each person. Effects of applying cold or cryotherapy Cold has a vasoconstriction action, that is, it contracts blood vessels and reduces blood flow in the area where it is applied . This reduces the amount of blood and circulation in that area, which causes a reduction in edema (swelling) and also in hemorrhage (for example when hematomas form). It also reduces sensitivity in the area where it is applied, thus reducing pain, and slows down the transmission of pain signals by nerves to the brain, resulting in less perception of pain. Further, it reduces metabolism, limiting tissue changes during acute injuries, which can help prevent further damage and speed recovery. While cryotherapy is generally safe for many people, it is not suitable for everyone . It is always important to consult a healthcare professional before beginning any cryotherapy treatment to ensure it is safe for each specific situation. Effects of applying heat or thermotherapy Heat promotes the dilation of blood vessels – it is a vasodilator. Thus, it increases blood flow in the region where it is applied . The arrival of more oxygen and nutrients and the increase in metabolism accelerate the healing process. Heat also promotes relaxation of muscles and ligaments. When to apply cold and heat Cold is suitable for acute injuries and recent inflammations, such as sprains, strains, tendonitis, bruises, among others. Heat is suitable for chronic injuries, muscle tension and joint stiffness, like cramps, arthritis, chronic lower back pain, muscle spasms. In cases of injuries, as a rule, cold is applied first and then heat , but without alternating between the two. Cold is most appropriate immediately after an injury because there is almost always associated pain, inflammation, and swelling (edema). Heat is appropriate in the recovery phase. If there are no other indications, cold is applied : As soon as possible after an injury; At least 4 times a day, sometimes more, for periods of 10-20 minutes; It should not be applied directly to the skin, but protected; Cold application is maintained for 72 hours after the injury. And heat is applied : After 72 hours after an injury, when the worst phase of inflammation and swelling has passed; Can be applied for longer periods, 20-30 minutes, 4 or more times a day. How to apply cold and heat Among the options for applying cold are, for example: Towel/cloths/compresses (clean) wetted in cold water and wrung out and placed in the refrigerator or freezer; Ice cubes (or other frozen materials); Ice or gel pads that keep in the fridge or freezer. There are several options for applying heat , for example: Towels/cloths/compresses (clean) soaked in hot water and wrung out or soaked in cold water, wrung out and heated in the microwave; Specific thermal pads/bags for applying heat, either electric or filled with corn seeds or cherry pits, for example, which are heated in the microwave; Hot shower or bath. Attention: Both cold and heat can cause burns, so a barrier, such as a towel or cloth, should be used between the source and the skin . Furthermore, the duration of application and daily number of applications must be respected. People with diabetes, vascular diseases, skin diseases, sensitivity or vascular problems should avoid cryotherapy and thermotherapy without prior guidance from health professionals. If necessary, call LUZ 24 – 217 104 424 – the telephone clinical triage service of the Hospital da Luz network, available 24 hours, 365 days, for adults and children. Use the QR Code and save the LUZ 24 contact on your mobile phone. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
