One of the most common questions I get on the topic of injuries is “Should I apply heat or ice?” The general rule of thumb is you will never go wrong if you put ice on an ache or pain, but you may go wrong if you use heat.
When should I use ice?
Ice should be applied to the affected areas as soon as possible, especially in the first 72 hours after an injury has occured. It is important to do this because ice will reduce the swelling by decreasing the blood flow to the area, which is what you want. While some blood flow is necessary to carry healing cells to the affected area, there is not too much concern in restricting it since the blody always over produces blood anyway. Using ice also decreases the amount of time an injury needs to heal and by numbing the area, it reduces pain and discomfort.
When using ice, expect it to be uncomfortable at first. You typically experience the following sensations: cold, aching, burning and numbness. Once you reach numbness, simply remove the ice. Apply it on average 10-15 minutes, or until the area is numb, every 1 1/2-2 hours or so. Good examples of ice packs include a bag of frozen vegetables, ice chips in a zip-lock bag, water frozen in a paper or foam cup, or commercial gel packs (best for superficial areas, like a thumb or toe).
Injuries such as ankle sprains, which require ice and compression respond well to tensor or Ace bandages which have been soaked in water before being wrapped around the swollen area. Never apply ice directly to the skin; always use a thin wet towel between the skin and ice to prevent frostbite. The exception to this rule maybe frozen vegetable bags, which sometimes do not get as cold as pure ice.
When should I use heat?
The best advice I can give to applying heat to an injury is if a health practitioner has prescribed it to you.
Heat is used when an increase of blood flow is necessary to an affected area. This is usually required for chronic conditions (after 6 months and more) like a strained hamstring that after months is still very tight and some soreness is still present. Applying heat to the area will bring blood to the muscle and release the spasm, which allows for easier stretching of the muscle.
One important note is to always use moist heat. Dry heat, like an electic heating pad, only heats the surface of the skin. It does not penetrate deep enough into the muscles like moist heat. Examples of moist heat include a hot water bottle with a damp towel underneath, a hot tub, shower or bath. Hope this helps!