Thyroid function changes during pregnancy and maternal thyroid dysfunction have been associated with adverse outcomes. Our aim was to evaluate thyroid hormones levels in pregnant women resident in Aragon, Spain.

Objective: To determine the influence of age, training status, race time, and exercise intensity on the appearance of cardiac biomarkers after a cycle-touring event. Design: Pre-post exercise measurements. Setting: University of Zaragoza, Zaragoza, Spain. Participants: Ninety-one amateur cyclists. Intervention: The 2005 Quebrantahuesos cycle-touring event (distance: 206 km; altitude difference: 3800 m). Main Outcome Measures: Cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) were measured the day before and immediately after the race. Heart rate (HR) monitoring was performed on 55 cyclists during the race to evaluate exercise intensity. Results: cTnI and NT-pro-BNP were significantly elevated immediately post race, with 43% of participants exhibiting cTnI levels greater than 0.04 μg/L and 65% of the participants measuring NT-pro-BNP levels greater than 125 ng/L. The cTnI increase was significantly associated with mean exercise intensity HR (r = 0.36, P < 0.01) but was not associated with age, training status, or race time. The increase in NT-pro-BNP correlated with race time (r = 0.40, P < 0.001) and training status (r = −0.36, P < 0.001) but was not associated with age or exercise intensity HR measures. Conclusions: These results suggest that, in part, exercise intensity (HR) is responsible for the cTnI increase and that race time is responsible for the increase in NT-pro-BNP. Future standardized endurance exercise trials are recommended to further elucidate the potentially differential effects of training status, exercise time, and intensity on post-exercise increases in cTnI and NT-pro-BNP.