The effect of stress on reported pain

The chronic and acute effects of stress can have divergent effects on health; long-term effects are associated with detrimental physical and mental health sequelae, while acute effects may be advantageous in the short-term. Stress-induced analgesia, the attenuation of pain perception due to stress, is a well-known phenomenon that has yet to be systematically investigated under ecological conditions. Using Flo, a women’s health app with a world-wide monthly active usership of more than 48 million, women in Ukraine were monitored for their reporting of stress, pain and affective symptoms before, and immediately after, the onset of the Russian-Ukrainian conflict. To avoid potential selection (attrition) or collider bias, we rely on a sample of 87,315 users who were actively logging multiple symptoms before and after the start of the war. We found an inverse relationship between stress and pain, whereby higher reports of stress predicted lower rates of pain. Stress didn’t influence any other physiological symptoms
with a similar magnitude, nor any other symptom had a similar effect on pain. This relationship generalised with decreasing magnitude to countries neighbouring Ukraine, with Ukraine serving as the epicentre. These findings help characterise the relationship between stress and health in a
real-world setting.