Heat vs Ice for Soft Tissue Healing
Soft tissue damage is a relatively common injury and certainly not one which exclusively affects elite athletes. Most of us at some point will suffer from pain, redness and swelling and often resting the area affected will lead to full recovery.
There are a variety of techniques that are often used to promote quicker healing, including manual lymphatic drainage, specific exercise routines and massage.
But in this post, we will look at the application of both heat and ice to help promote soft tissue healing and explore what the current evidence says about each approach.
Physiology of Soft Tissue Healing
Everything in the human body is considered a soft tissue, excluding the bones of the skeletal system. There are four different types:
- Epithelial tissue (including skin and organs).
- Connective tissue (including ligaments, cartilage, tendons, blood vessels, and fat)
- Muscle tissue (including the heart)
- Nervous tissue (brain, nerves and spinal cord)
When soft tissue is damaged, the healing process isn’t simply a physiological reaction that replaces like with like. It can often mean that the tissue affected adapts, for example, by replacing the original type with another (for example, scar tissue). There may also be an abnormal development of the tissue or a reduction in size because certain cells die and are not replaced.
The healing process starts almost as soon as an injury occurs. There are three phases which often overlap each other.
The first of these is the inflammatory response where the injured area appears red, swollen and is generally painful. Healing cannot take place if this phase doesn’t happen and it’s often accompanied by the release of cytokines, histamine, and leukotrienes which begin the process of recovery.
The next stage is fibroblastic repair where the injured area begins to ‘renew’ itself with the body producing collagen to aid this process. Finally, there’s a maturation-remodelling stage where the new area that is formed is transformed into some form of functional tissue.
One of the key factors at each stage of the healing process is the level of the vascular supply. Areas with poor circulation tend to heal more slowly and can mean a lack of essential components such as fibroblasts prevent the formation of scars.
Heat and Soft Tissue Healing
Applying heat to an injured area can support the healing process and produce several physiological effects. It helps reduce pain, relax the muscles and improve the flexibility of scarring in the long term.
Heat can be applied in a variety of different ways including through infrared lamps, baths and compresses. Research carried out in 2004 by Goto found that heat therapy may well play a role in reducing the atrophy in cells and muscles, promoting better protein synthesis during the healing process.
Research by Gao in 2015 also discovered that the application of heat therapy could promote stem cell growth in surrounding muscles and increased metabolism following injury or surgery. Another study by Takeuchi et al in 2013 suggests that the application of heat can help improve muscle regeneration and reduce collagen deposition.
Ice and Soft Tissue Healing
The concept of the ice bath or applying an ice pack to help aid healing and reduce swelling has been prevalent in sports for a long time. The research, however, does not support the use of ice for soft tissue healing.
As far back as the mid-1980s, Knight looked at the effects of ice therapy on injuries and found that it reduced inflammation – the important first stage in healing – but increased swelling and lowered the immune response.
Meeusen in 1986 found that ice treatment also had a profound negative effect on the lymphatic system and could even damage small blood vessels, reducing the body’s natural healing process. The lymphatic system is seen as one of the most important parts of soft tissue healing and not only helps reduce swelling but removes damaged and dead cells.
A study by Bassett in 1992 also discovered that ice treatment could also cause more damage to peripheral nerves. A systematic review by Collins in 2008 found that there was little or no support in the literature for the use of cryotherapy in the treatment of soft tissue damage.
There is a good deal of evidence that suggests a strong healing process depends on a healthy metabolism where there is a good blood flow to the injured area. Ice inhibits this process despite the common misconception that it can reduce problems such as swelling and promote healing.
It’s also clear that the lymphatic system plays a significant role in reducing swelling and promoting healing. With improved metabolism, the body has a better chance of building new functional tissue and this is best achieved through the application of heat. The primary role that ice seems to play is in helping reduce initial pain – the other effects are largely negative.