Purpose: Alterations in immunological homeostasis induced by acute exercise have been frequently reported. In view of the growing amount of repetitive exercise stimuli in competitive sports, quick recovery plays a superior role. Therefore, we examined whether aqua cycling affects cellular immunological recovery.
Methods: After performing 300 countermovement jumps with maximal effort male sport students (n = 20; 24.4 ± 2.2 years) were randomized into either an aqua cycling (AC) or a passive recovery (P) group. AC pedaled in chest-deep water without resistance, while P lay in a supine position. Each recovery protocols lasted 30 min. Blood samples were taken at Baseline, Post-exercise, Post-recovery and 1 h (h), 2 h, 4 h, 24 h, 48 h and 72 h after recovery. Outcomes comprised white blood cell (WBC) counts, lymphocyte (LYM) counts and LYM subsets (CD4/CD8 ratio). Additionally, cellular inflammation markers (neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and systemic immune-inflammation index (SII)) were calculated.
Results: In both groups, WBC, NLR and SII were significantly increased compared to Baseline up to and including 4 h after recovery. Significant interaction effects were found for WBC (Post-recovery, 2 h and 4 h), NLR (Post-recovery), SII (Post-recovery) and CD4/CD8 ratio (2 h) with values of AC being higher than of P.
Conclusions: Interestingly, AC provoked a stronger but not prolonged immunological disturbance than P. NLR and SII may present simple, more integrative markers to screen exercise-induced alterations in immune homeostasis/recovery in athletes and clinical populations. More research is warranted to elucidate the clinical and practical relevance of these findings.
Keywords: Aqua cycling; Exercise; Immune cells; Inflammation; Recovery.