Ice vs. Heat: Which Is Best for Your Injury?

There’s always some level of pain and inflammation associated with an injury. But what’s the best way to treat it—ice or heat? 

“Pain is the way our body lets us know that there is an injury and that our body is trying to recover,” says Nick Woodard, DPT, ATC, a Mass General Brigham physical therapist. 

Woodard works with patients at Wentworth Douglass Rehabilitative Services at Marsh Brook. He describes how to best use ice or heat to treat an injury.

What is inflammation?

Inflammation is our body's natural healing process. Without it, we would never recover from our injuries.

While both pain and inflammation are necessary aspects of the healing process, they can be overbearing at times. Typically, the more significant an injury is, the more pain and inflammation you experience.

There are many options out there for pain and inflammation management with two of the most frequently used approaches being ice (also known as cryotherapy) and heat (also known as thermotherapy). 

Ice

For acute traumatic injuries such as a joint sprain or muscle strain (pull), ice is the first line of defense for getting the acute pain, inflammation, and swelling under control. 

Ice packs work by:

• Decreasing pain through decreasing nerve conduction velocity
• Minimizing swelling through vasoconstriction
• Decreasing muscle spasms
• Decreasing cellular metabolism

There are many forms of cryotherapy (icing) outside of ice packs. Alternative forms of cryotherapy include:

• Ice cup massages
• Ice baths
• Cold compression machines
• Vapocoolant sprays

How to apply ice for injuries

When applying cryotherapy in the form of an ice pack, you’ll want to apply 1 to 2 towel layers between the ice pack and the skin. An ice pack should be applied for 15 to 20 minutes to achieve the desirable effects.

Downsides of using ice for injuries 

Reasons to avoid cryotherapy (ice) include:

• Impaired circulation (Raynaud’s disease)
• Cold induced hives (urticaria)
• Decreased sensation to touch or pain on the area of application
• Hypersensitivity to cold
• High blood pressure or peripheral vascular disease
  

Heat

For chronic muscular pain or pain related to chronic osteoarthritis, heat can often be more beneficial for its ability to relieve muscle tension and calm the nervous system.

Hot packs work by:

• Increasing blood flow to injured tissues through vasodilation
• Increasing extensibility of connective tissues
• Relaxing muscle spasms
• Increasing cellular metabolism 

There are also many forms of thermotherapy (heating), which include:

• Warm whirlpool baths
• Fluidotherapy
• Laser therapy
• Paraffin baths
• Continuous ultrasound
• Physical activity  

How to apply heat for injuries

When applying thermotherapy in the form of a hot pack, it is important to read the instructions of the hot pack to avoid potential complications including burns.

Hot packs typically require 6 to 8 layers of toweling between the hot pack and skin. It is important to check the skin under the hot pack 5 minutes after initial application to monitor for excessive redness, blistering, and signs of redness.

Downsides of using heat for injuries

Reasons to avoid thermotherapy (heat) include: 

• Acute traumatic injuries (joint sprain, muscle strain, bone fracture) 
• Acute inflammation (within 6 days of an acute injury)
• Decreased sensation to touch or pain on the area of application

“While both ice and heat can be useful for managing pain and inflammation, in general, ice is better for acute or traumatic injuries, and heat is better for chronic pain,” says Woodard. “If you have questions regarding the use of ice or heat for your specific injury, your athletic trainer will be able to guide you on which modality will work best for you.”