FITNESS IN THE FIT - DOES PHYSICAL CONDITIONING AFFECT CARDIOVASCULARRISK-FACTORS IN MIDDLE-AGED MARATHON RUNNERS

Objective The study was designed to assess cardiovascular risk factors in marathon runners with different degrees of fitness. Design A total of 30 male middle-aged marathon runners were divided according to the ir marathon running time into fit (265 +/- 8 min), fitter (222 +/- 5 m in) and fittest (178 +/- 12 min). The three groups of 10 runners each were comparable in age, weight, and body surface area. Cardiovascular risk factors were assessed by measuring arterial pressure before and d uring exercise (150 watts) and determination of plasma lipoproteins, u ric acid, glucose and white blood cell count before and after a marath on run. Results All measured laboratory values such as high density li poprotein cholesterol (P < 0.05), low-density lipoprotein cholesterol (P < 0.05), total cholesterol (nonsignificant), triglycerides (non-sig nificant), blood sugar (non-significant), uric acid (P < 0.01) and whi te blood cell count (P < 0.05) indicated a lower cardiovascular risk i n the fastest when compared with the slowest runners. Resting blood pr essure was similar in the three groups but consistently lower at all l evels of exercise in the fittest when compared with the less fit runne rs. The fittest runners also showed greater increases in high-density lipoprotein cholesterol after the marathon run (14% vs 8% in the slowe st runners, P < 0.005). Conclusions We conclude that even at the extre me end of a continuum such as represented by well-conditioned, middle- aged marathon runners, cardiovascular risk factors are related to the degree of fitness, as measured by the marathon running time.