Heat Vs Cold
There are 2 sources of pain in most injuries:
Inflammation (swelling at the site of injury). The less inflammation you have the quicker the injury heals
Pain in muscles around the injury which tighten, splint, and protect the injured area
Cold and heat can be used to ease pain and accelerate the healing.
Cold is used to minimise inflammation, kill pain and relax muscle. It should be used for the first 48-72 hours after injury as inflammation develops throughout that period. The more you minimise inflammation, the faster your recovery will be.
Pain relief will last until the area warms up again.
Ideally an inflamed area should be iced for 10 mins on, 10 mins off, 10 on again every 2 hours that you are awake in the 72 hrs after injury. However, 2-3 sessions per day will be sufficient in many cases.
Heat is used to promote blood circulation and relax muscles to assist in healing. It should be used on the 3rd or 4th day after injury. If used too soon after an injury it will make the area swell more and thus prolong the healing time, even though it will relieve a part of your pain due to muscle spasm. Hot showers are included here. Leave a wheat bag or hot water bottle on for 15-20mins and repeat 2-3 times per day.