Why do you need cold compress after sports injury?

Both cold compress and hot compress are commonly used methods to deal with sports injuries, each with its own advantages and different mechanisms. Cold compress can promote vasoconstriction, relieve local congestion, inhibit sensory nerves, and has the functions of cooling, hemostasis, analgesia and detumescence; Generally, it should be carried out within 24 hours after injury, and the earlier it starts, the better. Because the capillaries will contract at this time, reducing local congestion and relieving pain. In sports competitions, it is often seen that rescuers spray medicine on the injured parts of athletes, and the athletes who fall to the ground immediately magically stand up and join the competition in full spirit. The "panacea" used by ambulance personnel is chemical refrigerant. Hot compress can promote local vasodilation, improve local blood circulation and lymphatic circulation, facilitate the absorption of congestion and exudate, and have the functions of reducing swelling and pain, reducing adhesion and promoting wound healing. When the swelling of the injured part no longer progresses, hot compress should be carried out. It is usually carried out after 24~72 hours of injury, when the local capillaries have stopped bleeding. Hot compress can effectively improve local blood circulation, accelerate the absorption of congestion and exudate, and promote the early repair of sprained tissue. If hot compress is applied immediately after injury, the local blood circulation will be accelerated, and the broken or incompletely broken capillaries between tissues will expand after heating, and the bleeding will increase and the swelling will be aggravated. It can be seen that cold compress and hot compress have their own adaptation ranges, and proper timing will get twice the result with half the effort; If you don't grasp it properly, it will be counterproductive. The general principle is: use cold compress in acute phase and hot compress in chronic phase. (Dr. Ke)