People often find it interesting to know that their pain threshold changes, it is often presumed that it’s set at a constant setting. Pain thresholds are subjective and everyone will have a different threshold, but your threshold will also vary on a day by day and even hourly by hourly basis and there are various factors that can cause it to shift. You can tolerate more or less pain depending on your mood or situation. Things that will cause your threshold to drop are stress, low mood and generally feeling tired or run down. The pain threshold decreases here as a protective mechanism, if you’re tired or stressed you will generally feel more aches as a consequence of the nervous system perceiving there to be more threat or feeling it does not have the resources to deal with the threat and so being more protective.
Studies have shown that your pain threshold can drop quite quickly in certain situations. One study found that if they made people feel more depressed then they could tolerate less of a heat stimulus before it became painful. In another study they found that putting people in stressful situations reduced the ability for them to tolerate a heat stimulus before it became painful. This happened in a relatively short period of time in both studies.
If you are interested in these studies the links can be found here:
Changes in motivation can cause an increase in the pain threshold. When people are playing sport their pain threshold will increase in order for them to achieve their goal of winning the match. When you are more relaxed the pain threshold increases, if you meditate, which helps to relax the nervous system and the muscular system, you can tolerate a higher level of pain. This can also happen fairly quickly. This study found that after fours days of practicing meditation people’s tolerance of heat increased before it became painful, compared to their pre-meditation levels. Follow the link for this study:
This might be why this meditating monk can smash a brick over his head:
So, how does the brain change the threshold? Well the brain has a mechanism where it can send a message to the central nervous system, specifically certain cells in the spinal cord, to tell them to change the messages that come in from peripheral parts of the body. So, previously non-painful stimulation like a gentle touch on the skin can feel painful, even though it is not causing any harm to your body, because the signal that comes in is now an amplified signal. The brain uses this mechanism to protect you from perceived threat and this threat can be physical or psychological. If someone is relaxed then there is less perceived threat and the threshold increases.
If you have had a recent acute episode of pain, have a think about what was happening and how you were feeling at the time, as it may not have been a mechanical problem which caused the pain, it may have been the nervous system trying to protect you from a perceived threat.