Cardiorespiratory fitness and pain severity: Longitudinal associations from the general population-The HUNT study

Reduced cardiorespiratory fitness (CRF) is associated with chronic pain, but longitudinal population-based evidence is limited. Whether CRF can prevent pain worsening or promote improvement is unclear.

This study investigated (1) the cross-sectional association between estimated CRF (eCRF) and chronic pain, (2) the longitudinal association between eCRF and changes in pain severity over 11 years, and (3) whether changes in eCRF are associated with changes in pain severity.

Data were collected from the Trøndelag Health Study (HUNT) in Norway. Cross-sectional analyses included 18,837 adults from HUNT3 (2006-08), and longitudinal analyses followed participants to HUNT4 (2017-19), stratified by baseline pain status: no or mild (n = 11,517) or moderate/severe chronic pain (n = 5312). Cardiorespiratory fitness was estimated using a validated nonexercise algorithm and categorized into sex- and age-specific quintiles. Logistic regression estimated odds ratios with 95% confidence intervals.

Cross-sectionally, higher eCRF was associated with lower odds of chronic pain, with the largest difference between the highest and the lowest quintiles (women: OR 0.56, 95% CI 0.49-0.64; men: OR 0.64, 95% CI 0.53-0.78). Longitudinally, among participants with no or mild pain, both high baseline eCRF and maintained high eCRF were associated with lower odds of pain worsening. Among those with chronic pain, maintaining or increasing eCRF was associated with greater odds of pain reduction, whereas high baseline eCRF showed a nonsignificant trend in the same direction.

Higher eCRF was associated with lower odds of chronic pain and with more favorable changes in pain severity in the general population.