More Sugar More Pain?

Many patients tell me they have a high threshold for pain. Until I start to work on them. Then they change their mind (not everyone of course).

Being in the pain business (i.e. finding the cause of patients' pain and treating it), I've always been intrigued about how we tolerate pain. Some patients can definitely tolerate pain better than others.

The article referenced below (Ye et al, 2022) definitely caught my eye. The researchers investigated the effects of high blood sugar on pain sensitivity and pain inhibition (the act of stopping or slowing down pain) in healthy adults with normal and excess body fat.

The researchers found that ingesting just 75 grams of glucose (2 standard cans of soft drink) in the overweight group of subjects caused the subjects more pain when both their feet were submerged in cold water for 1 minute.

In addition, having acute hyperglycaemia (high blood sugar levels) also suppressed resting heart rate variablity (HRV) in the group with excess fat mass. *HRV is where the amount of time between your heart beats fluctates slightly.These fluctuations can indicated current or future health problems like heart conditions or anxiety and depression.

Regardless of blood sugar levels, the group with excess fat mass could not tolerate the pain from a pin prick after cold water immersion. This group also reported higher pain levels during a 5-minute period of blood flow occlusion.

In addition to the effects of high blood sugar on pain sensitivity and pain inhibition, effects on HRV and reactive hyperaemia (increase of blood flow) after arterial occlusion were also investigated. Both high blood sugar and excess body fat affected HRV and reactive hyperaemia only in people with extra fat mass.

Interpreted together, the researchers concluded that high blood sugar levels affected pain processing levels and autonomic function, especially in people with excess body fat mass. 

So, if you are overweight and consume more than 75 grams of sugar (2 standard cans of soft drinks) you will more likely feel more pain compared to someone who is not overweight.

The authors added that since both hyperglycaemia (high blood sugar levels) and being overweight are risk factors for diabetes, further research should be done on whether and how these sources of pain affects people with diabetes.

Reference

Ye D, Fairchild TJ, Vo L et al (2022). High Blood Glucose And Excess Body Fat Enhance Pain Sensitivity And Weaken Pain Inhibition In Healthy Adults: A Single-blind And Cross-over Randomised Controlled Trial. J of Pain. In Press, published 16 Sep 2022. DOI: 10.1016/j.pain.2022.09.006

*HRV responds uniquely for everyone. As a rule of thumb, values under 50 ms are unhealthy, 50-100 ms signal compromised health and readings above 100 ms are healthy.