Differences in Transfer Factor of the Lung between Rest and after Maximal Exercise in Croatian Junior and Senior Rowers

Background: Aerobic capacity is of decisive importance for cyclic physical activities lasting longer than three minutes. Rowing is a particularly demanding activity because it is exactly the aerobic lung capacity that is the most important in performing that activity. Aerobic capacity depends on age, sex, genetic factors and, what is of particular importance, professionally guided training. The test of maximal possible reception of oxygen is considered to be the best test giving relatively reliable information about maximal aerobic capacity.

Aim: The aim of this paper is to determine the change of diffusing lung capacity for carbon monoxide (DLco) of Croatian rowers at progressive exercise on a rower`s ergometer.

Method: The research included 91 rowers (45 seniors; 46 juniors). Ergometric tests were performed on a rowing ergometer `Concept II` model C (Morrisville, Vermont, U.S.A.). Diffusing lung capacity for CO (DLco) and unit diffusion (DLco/Va) were measured at rest and after maximal exercise using the multifunctional apparatus `Master Lab` (Jaeger Company). Diffusing lung capacity was measured by the `single breath method`. Because of the great influence of the alveolar volume on the measured values of DLco (DLco progressively decreases by the reduction of Va to the level of the functional residual capacity), a correction of diffusing capacity to alveolar volume has been suggested and is termed unit diffusion or Krogh constant (KCO). Values after Cotes have been taken as normal values for diffusing capacity. The results were statistically processed by analysis of variance with the level of significance p0.05.

Results: The two samples were statistically significantly different in the three variables: age, body height and body weight as expected. The values of diffusing lung capacity at rest were 21.93±3.23 mmol/min KPa for juniors and 23.56±4.73 mmol/min KPa for seniors (p.05). Unit diffusion at rest was 2.41±0.30 mmol/min KPa L for juniors and 2.27±0.43 mmol/min KPa L for seniors (p.05). At the end of testing, after maximal effort, the values increased significantly by 1.2 times in both rowing patterns. Diffusing lung capacity for juniors was 26.04±3.31 (194.45±27.19% predicted) and for seniors 28.43±5.43 mmol/min KPa (208.54±39.14% predicted). Seniors have statistically significantly higher diffusing capacity (p.01) as well as predicted value (p .05). However, when the values of diffusion capacity are corrected for alveolar volume, no statistically significant difference between the two samples was found.

Discussion and Conclusion: In top athletes at rest DLco as well as DLco/Va are increased compared to standard norms after Cotes. Differences in diffusion capacity among rowers of different ages can be partially explained by considerably higher body height as well as on the associated larger alveolar surface.