| Popis: |
Objective: While it is well recognized that chronic exercise protects against the development of hypertension, acute exhausting exercise (AE) can induce large, transient increases in arterial blood pressure (ABP) and metabolic acidosis, which can be associated with pro-inflammatory response involving oxidant stress known to impair endothelial function.The aim of this study was to test the impact of acute exhausting rowing training on microvascular reactivity in sedentary subjects and trained rowers. Design and method: Healthy lean sedentary subjects (Sedentary) (N=8) and trained rowers (Trained) (N=8) underwent a single progressive rowing training to maximal exhaustion. Skin microvascular post occlusive reactive hyperemia (PORH) (indicator of endothelial function) was assessed by laser Doppler flowmetry (LDF) before and after AE. ABP, heart rate and oxygen saturation were measured before and after AE and between workloads. Body mass index (BMI) and waist to hip ratio (WHR) were measured in each subject. Plasma glucose, C reactive protein (CRP) and lactate levels, as well as, arterial blood gas analysis and acid base status were measured before and after AE. Results: All subjects were normotensive age- matched males, with no difference in BMI, WHR, control ABP and heart rate between groups. At baseline, Trained had significantly higher PORH compared to Sedentary (P=0.003). While AE didn't induce any significant change in PORH in Sedentary (P=0.471), PORH was significantly impaired in Trained after AE (P=0.016). Serum lactate and glucose levels significantly increased, and metabolic acidosis occurred, while oxygen saturation decreased after AE in both groups. CRP significantly increased in Sedentary after AE. Systolic blood pressure (SBP) significantly increased during AE in both groups, but more prominent in Trained compared to Sedentary. Increment of SBP during AE tended to adversely correlate with PORH (P=0.068). Conclusion: These data suggest that a single progressive rowing training to maximal exhaustion impaired microvascular reactivity in trained rowers but not in sedentary subjects, possibly due to 1) higher transient increase in arterial pressure that occurred in trained rowers and/or 2) change in sensitivity to metabolic acidosis during exertion in athletes. |
