Relationship of inflammatory response and mood to high-intensity interval exercise

The current study compared the acute inflammatory response and the relationship to mood following two intensities of high-intensity interval exercise (HIIE). Eight physically active males (25 ± 6 years; 49.02 ± 5.53 mL·kg⁻¹·min⁻¹) undertook two 20-minute HIIE trials (10 × 1-minute intervals at 80% (HIIE80) and 90% (HIIE90) interspersed with 1-minute active recovery). Plasma interleukin-6 (IL-6), leukocyte counts, and Brunel Mood Scale (BRUMS) mood ratings were collected before (pre), immediately after (post), 30 minutes (post30) and 60 minutes (post60) post-exercise with an additional measure of mood 24 hours post-exercise (post24 h). Feelings of tension were significantly reduced post30 (P = 0.003), post60 (P = 0.001) and post24 h (P = 0.01) following HIIE80. Correlations between IL-6 and mood identified a significant negative relationship between IL-6 and fatigue 30 minutes after HIIE80 (r = −0.78, P = 0.02). Inflammatory response did not significantly differ between exercise intensities; however, only HIIE90 was sufficient to elicit a significant transient increase in IL-6 (2.64-fold) which may provide an effective strategy to target inflammatory dysregulation. Future studies are required to establish the long-term implications of the anti-inflammatory properties of HIIE on mood.