Author(s): ROSA NETO, J., CARVALHO N; FIGUEIREDO C; LUCENA RAMOS B; TANHOFFER RA; LIRA FS; UCHIDA MC; PEREIRA-ROSA JP; LOURENÇO T; OLIVEIRA-FILHO CW; , Institution: UNIVERSITY OF SAO PAULO: UNIVERSIDADE DE SAO PAULO, Country: BRAZIL, Abstract-ID: 2320

INTRODUCTION:
Acute exercise induces transient immune alterations, typically characterized by increased leukocyte counts driven by neutrophilia and relative lymphocyte reduction. In Paralympic athletes, autonomic dysfunction and severity of impairment may modulate these responses. This study investigated hematological and biochemical responses to an acute exercise bout in Brazilian National Wheelchair Rugby athletes, stratified by sport classification (≤ 2.0 – high vs. > 2.0 – lower severity). We hypothesized that the severity of impairment would influence exercise-induced hematological changes.
METHODS:
Blood samples were collected before and 30 minutes after the technical training session. Biochemical markers (creatine kinase, lactate dehydrogenase, HDL cholesterol, glucose, urea, ALT, and AST) were measured by colorimetric assays. Complete blood counts were obtained using an automated hematology analyzer.
Statistical analysis
Generalized Estimating Equations (GEE) were used to evaluate the effects of group (classification ≤ 2 vs. > 2), time (pre- and post-exercise), and the group × time interaction on all outcome variables. Bonferroni post hoc tests were applied when appropriate. For each variable, models were fitted assuming either a normal distribution with an identity link or a gamma distribution with a log link. The best-fitting model was selected based on the quasi-likelihood under the independence model criterion (QIC). An exchangeable working correlation structure was adopted for all analyses. Results derived from the GEE models are presented as means and standard deviations. All statistical analyses were performed using IBM® SPSS Statistics (version 26), and figures were generated with GraphPad Prism (version 10.6.1). Statistical significance was set at p ≤ 0.05.

RESULTS:
Creatine kinase levels were higher in athletes with a sport classification > 2.0. This group also showed an increase in nucleated red blood cells after exercise. As expected, acute exercise increased total and relative neutrophils and reduced the percentage of lymphocytes.
CONCLUSION:
These findings suggest that sport classification influences exercise-induced hematological responses in wheelchair rugby athletes. Although the overall immune pattern was consistent with the classical acute exercise response, athletes with lower impairment severity exhibited distinct biochemical and erythroid alterations.
Acknowledgment: This study was conducted by the Multidisciplinary Center for Paralympic and Para-sport Studies in partnership with the Brazilian Paralympic Committee and the Brazilian Wheelchair Rugby Association. São Paulo Research Foundation (FAPESP) # 2025/07056-9.