Mood Disturbance Following Physical Activity (PA) Withdrawal is Associated with Greater Inflammatory Responses to Stress

Background Regular PA is thought to have positive effects on well-being, which might also be explained by anti-inflammatory processes. Previous research has shown that PA is inversely associated with inflammatory responses to stress but this work has been cross-sectional. Given the pivotal role of stress in promoting inflammation and depression, it is important to examine these mechanisms experimentally.

Aims The aim of the study was to test whether negative mood induced by PA withdrawal is associated with inflammatory responses to stress.

Method Forty-seven active participants (V0_2peak 46.85±8.86 age 24.28±4.98 y) were randomized to 2 week PA withdrawal or 2 week PA maintenance (control) in a cross-over, controlled design. Stress testing was carried out at the end of each 2 week PA condition. Adherence to the protocol was measured with accelerometers, and changes in mood with the General Health Questionnaire (GHQ). Peripheral blood was sampled at baseline and 45m after stress and assayed for the inflammatory marker interleukin (IL-6).

Results Participants reported significant increases in negative mood following PA withdrawal (GHQ 19.72±9.7 vs. 13.64±6.06; p=0.001) compared with PA maintenance. In a stepwise linear regression analysis age, gender and BMI were not associated with the IL-6 responses. After adjusting for 1 L-6 response during PA maintenance, negative mood change was positively associated with IL-6 stress response during PA withdrawal (Beta=0-42, p=0.02) explaining 12% over and above the variance explained by the IL-6 response at control (Tot R2=0.30).

Conclusion These data show that participants who experienced greater negative mood following PA withdrawal had heightened IL-6 during mental stress.