Higher left ventricular wall thickness and forearm blood flow may be associated with higher systolic blood pressure in swimmers

In healthy individuals, swimming seems to increase resting systolic blood pressure (SBP). However, the mechanisms responsible for SBP elevation associated with swimming have not been elucidated. Therefore, this study investigated cardiovascular morphology and function in healthy young male swimmers. Brachial SBP was higher in swimmers than non-swimmers. Left ventricular (LV) wall thickness and forearm blood flow (BF) and vascular conductance (VC) were also higher in swimmers relative to non-swimmers. In a stepwise regression analysis that included physical characteristics and cardiovascular morphology, LV wall thickness was an independent predictor of brachial SBP. When parameters related to cardiovascular function were added to the analysis, forearm BF and VC were identified as independent predictors of brachial SBP. LV wall thickness was correlated with forearm BF. Increases in BF to the forearm muscles may explain the brachial SBP elevation in swimmers. LV wall hypertrophy may be associated with brachial SBP elevation via increases in forearm BF.