The Effect of Endurance Exercise and its Intensity in Middle- aged Runners; Are they Thrombogenic?

Abstract

Introduction Despite the well documented benefits of regular exercise, acute exercise induces a transient hypercoagulable state with increasing risk of thrombotic disease with age and intensity. While prior studies have used various conventional coagulation tests in studying the influence of exercise on coagulation, limited attention has been given to clot microstructure and contraction profile in well-trained individuals of middle to older age. Our aim was to identify effects of exercise on these variables using hemorheological biomarkers. Materials and methods Twenty-eight male and female runners aged over 40 years completed a 10 km run at moderate intensity. Of these runners,14 were reinvited to complete a 3 km run to exhaustion. Blood samples were drawn at three time-points, baseline, immediately after exercise and after 1 hour of recovery. Structural biomarker df and measurements of mature clot mechanical properties (Maximum Contractile Force and G’Max) were analysed alongside conventional coagulation markers. Results While df remained stable following long moderate intensity exercise, higher intensity exercise caused an increase in df indicating a hypercoagulable phase. Following an hour of rest, df returned to baseline. These results indicate that the effect of acute exercise on hypercoagulability is intensity dependent and transient. Maximum Contractile Force (CFMax) was reduced by exercise, irrespective of intensity. This effect was lower after an hour of rest, suggesting that some unknown initial compensatory mechanisms are outlasted by a longer period of reduced contractile force. Conclusion df and CFMax detected the hypercoagulable phase that occurred in trained older individuals as a result of exercise. Investigating these effects in more sentient populations could allow risk stratification of exercise rehabilitation programmes and their intensity