The difference between chronic and acute pain

What is the difference between chronic / persistent pain and acute pain? 

Acute pain describes pain that comes for a short while and then clears up (normally around 3 months) once the injury is healed. It is a warning sign that our nervous system generates in response to a perceived threat (e.g. injury). It is a helpful response – it gets us to seek medical attention, rest and recover.  

On the other hand chronic, or persistent pain describes pain that lasts longer than 3 months. Chronic pain does not mean it is more dangerous or threatening than other types of pain.  

Why do people feel acute pain? (short term pain) 

The brain has one goal: keeping us safe and helping us respond to threats. This protective reaction is called the stress response. The stress response has lots of ways to keep us safe, and experiencing pain is one way to do that. It is like an alarm system to make us aware of problems with the body, so we can fix them.  

For example, if you fall and break your leg, the brain will automatically activate the stress response to keep you safe, and you will feel pain, so you know to go to the hospital. You will continue to feel pain so that you stay off the leg and allow it to heal. 

Once the bone is healed (normally within 3 months) the pain will stop, because the brain knows the threat (the injury) is gone and you are safe, so the stress response switches off.