SALIVARY STEROID CHANGES AND PHYSICAL PERFORMANCE IN HIGHLY TRAINED CYCLISTS

The purpose of this work was to study the seasonal salivary cortisol a nd testosterone changes, and their relationships with lean body mass v ariations, in highly trained cyclists. Physical fitness, body composit ion (6 skinfolds) and basal salivary testosterone were evaluated in 7 male cyclists, on two separate occasions. The first assessment was mad e at the onset of the competitive season and the second 6 months later . Two kinds of exercise tests were carried out. The first test was an incremental exercise test to determine the maximum O2 consumption (VO2 max) and the maximum workload (Wmax). We also measured the VO2 and wor kload (W) attained at die first and second ventilatory thresholds (VO2 VT1, WVT1, VO2VT2, WVT2). During the tests the VO2 was recorded every 30 seconds (Oxycon-5, Mijhardt BV, Odijk). As a second test two days l ater, we assessed the anaerobic capacity expressed as the maximal accu mulated O2 deficit (MAOD). Briefly, each subject underwent five submax imal exercises each lasting 6 min at an intensity of 200, 220, 240, 26 0 and 280 W. We estimated individually the O2 demand by extrapolating the linear relationship between the power and the O2 demand previously established. Afterwards the subjects performed a supramaximal bout at an intensity producing exhaustion between 2 and 4 minutes. The accumu lated O2 demand was calculated by multiplying the O2 demand by the sup ramaximal test duration. The MAOD was computed as the difference betwe en the accumulated O2 demand and the O2 consumed during the supramaxim al rides. We found a significant increase in some physical fitness par ameters related to aerobic capacity. The Wmax increased from 5.7 +/- 0 .5 to 6.1 +/- 0.3 W . kg-1 (p < 0.05); the WVT2 increased from 3.6 +/- 0.5 to 4.0 +/- 0.5 W . kg-1 (p < 0.05; the WVT2 increased from 4.4 +/ - 0.6 to 4.9 +/- 0.4 W . kg-1 (p < 0.05). The VO2max (from 75.7 +/- 4. 8 to 75.3 +/- 3.5 ml . kg-1 . min-1, p = NS), the VO2VT1 (from 51.7 +/ - 6.2 to 54.1 +/- 5.3 ml . kg-1 . min-1, p = NS), and the VO2VT2 (from 62.5 +/- 7.2 to 65.1 +/- 3.4, p = NS) showed a non-significant increa sing pattern. Nevertheless, the anaerobic capacity (expressed as the M AOD) decreased from 75.8 +/- 13.9 to 53.3 +/- 16.6 ml . kg-1 (p < 0.05 ). The cycling economy, as reflected by the steady state VO2 at 240 W, ameliorated slightly (from 55.5 +/- 5.3 to 53.5 +/- 3.2 ml . kg-1 . m in-1, p = NS), but the changes were non-significant. The subjects show ed a significant decrease in weight (from 64.3 +/- 3.6 to 62.5 +/- 3.6 kg, p < 0.05) and in lean body mass (from 60.4 +/- 3.5 to 58.4 +/- 3. 0 kg, p < 0.05). Salivary testosterone showed a non-significant decrea sing pattern (from 0.45 +/- 0.17 to 0.39 +/- 0.18 nmol/l,p = 0.15). Th e testosterone/cortisol ratio decreased by 29% (from 0.022 +/- 0.010 t o 0.016 +/- 0.005, p < 0.10), but this change did not reach statistica l significance. A firm correlation was found between increment of test osterone and increment of lean body mass (r = 0.87, p < 0.05). Our cyc lists increased their aerobic capacity, but they showed a deterioratio n of the anaerobic capacity. In spite of the high volume of exercise a ccumulated by these cyclists, the diminishing effect of endurance trai ning on testosterone was not significantly evident. Our findings sugge st that basal bioavailable testosterone changes are related to lean bo dy mass variations.