One of the most common questions I get in the office is regarding when to use heat or ice. In general, a little bit of either will never hurt you but too much of one or the other at the wrong time can be disastrous.
In general, there are three phases that most injuries or conditions go through prior to resolving: acute, sub-acute and chronic. The quick answer is that during the acute phase we follow the ice protocol; in the sub-acute phase we alternate heat and ice; and in the chronic phase we use primarily heat. Here's why:
The Acute Phase
The acute phase occurs the first 72 hours after injury (or onset of pain in the absence of injury) and it is the inflammatory phase. This is helpful in that it brings in the cells needed to clean up the area, but it's a problem because an injured tissue can't circulate out the waste products and inflammatory chemicals that the injury creates. Uncontrolled inflammation anywhere in the body causes damage and scar tissue, not just in back injuries but in any organ or blood vessel in the body. So minimizing the inflammatory process is very important in all aspects of health.
Ice is also analgesic, which means it dampens nociceptor (pain receptor) activity. That means it helps to reduce pain. So, although heat may feel better to you, ice is the appropriate choice from a physiological and healing perspective. We primarily use ice in the acute phase to minimize pain and inflammation.
The Sub-acute Phase
Depending upon the severity of injury, the sub-acute phase can last from days to weeks. During this period it is important to minimize swelling but to promote healing by increasing blood flow to circulate nutrients in and waste products out. The more time that products of injury and inflammation are left to stagnate in the area, the more scar tissue will form which will reduce overall healing. In general, we should follow an alternating ice-heat-ice protocol, always ending with ice. Heat brings blood to an area but the injured tissue can't process all the fluid that the heat brings, so we always finish with ice in the sub-acute phase to minimize the effects of the heat.
The Chronic Phase
In the chronic phase, most of the pain is gone and there can be stiffness and achiness. This phase can continue for weeks or months before resolution. During this period we really want to promote circulation to enhance nutrition to the tissues and to help to restore movement. Intermittent ice can be used if there is an unusual increase in pain. From a physiological perspective, heat is used in the chronic phase to improve tissue nutrition and range of motion.
How to Use Ice and Heat
Most importantly, always put a layer between your skin and the ice or hot pack. Frostbite and burns can be serious and lead to infection and scarring. I see both, frequently.
When using heat, dry heat is to be avoided as it does not promote circulation appropriately. Instead, hot showers, warm soaks with sea minerals, microwaveable herbal moist packs and plug in hydrocollators can be used. Never sleep with a plugged in source of heat.
For ice application, a flexible ice pack is the most comfortable and can be tucked inside some lumbar (lower back) braces or wrapped around an ankle or knee. A bag of frozen peas works well if you don't have an ice pack. Microwaveable herbal hot packs can also be put in the freezer and are a great alternative in the absence of an ice pack.
In general, I use an hourly 10 minute rule for application of ice or heat, although slightly longer times are okay. This means 10 minutes on, then leave it alone for an hour and repeat. When alternating ice and heat, it means: 10 minutes ice, 10 minutes heat, 10 minutes ice, then repeat the protocol in one hour.
These are the general guidelines for ice and heat application that I recommend for patients in my office, however, this is not a prescription for everyone and does not replace your physician's advice, especially in cases of diabetes and neuropathy. Please consult your doctor prior to beginning any therapeutic protocol.