AUTHOR=Edwards Sophie A. , Martin Sarah L. , Rainey Timothy , Whitaker Grace , Greenwood Darren C. , Jones Anthony , Sivan Manoj 

TITLE=Influence of acute fasting on pain tolerance in healthy subjects: a randomised crossover study

JOURNAL=Frontiers in Pain Research

VOLUME=Volume 4 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/pain-research/articles/10.3389/fpain.2023.1153107

DOI=10.3389/fpain.2023.1153107

ISSN=2673-561X

ABSTRACT=Background: Chronic pain and obesity are global health crises with substantial healthcare costs, yet little is known about the relationship between pain perception and eating behaviours. Food consumption is believed to provide an analgesic effect by the release of neurotransmitters modulating the pain network. It is however unclear whether short-term (acute) fasting affects pain perception.Purpose: This study aimed to investigate the effect of acute fasting on pain perception and whether attentional and mood changes drove observed changes.The pain tolerance of 25 healthy human participants was investigated in both non-fasted and 12 hrs-fasted sessions using a cold pressor test (CPT). They were randomised to either session with a cross-over to the other after at least 24 hrs with the experimenter blinded to the sessions. A Stroop task measured the pain tolerance in both attentive and distracted states. The mood was captured using the Profile of Mood States (POMS), and hunger was measured using a 10-point hunger scale. Mixed-effects models were used to investigate the influence of fasting and distraction on pain perception, accounting for the repeated measures.Results: Fasting reduced CPT pain tolerance, with fasting participants twice as likely to withdraw their hands early (HR=2.4, 95%CI: 1.3 to 4.5). Though men tolerated CPT pain longer than women, there was no evidence that men responded to fasting differently than women (p=0.9). There was no evidence that fasting affected attention or mood. Still, it did increase hunger by 2.7 points on a 10-point scale (95% CI: (1.2 to 4.2)) and decrease blood glucose concentrations by 0.51mmol/l (95%CI: 0.19 to 0.84).Acute fasting reduces pain tolerance in healthy subjects. This effect is independent of gender, attention, or mood changes.