2706 km cycling in 2 weeks: effects on cardiac function in 6 elderly male athletes

ABSTRACT

Objectives: Physiological effects of exercise on trained and untrained individuals have been studied extensively. Typically, young or middle-aged individuals are examined before and after short periods of vigorous exertion.

Methods: We studied 6 elderly male athletes (61 ± 8 years (mean ± SD); baseline O₂max 48 ± 5 ml·kg⁻¹·min⁻¹) with focus on cardiac function and biomarkers following 14 consecutive days of moderate intensity exercise. Cardiac dimensions, function, biomarkers, and other measures of cardiovascular health were examined at baseline and 2 and 28 h after the last day of cycling a total of 2706 km.

Results: Data collected after the cessation of exercise on the 14th day revealed significant increases in average size of the left atrium (3.5 ± 0.4 to 4.0 ± 0.3 cm; p = 0.02) and left ventricular end systolic volume (47 ± 2 to 52 ± 5 ml; p = 0.004), with no other significant changes in cardiac size or function. Small, transient increases in cardiac biomarkers (troponin T, creatine kinase myocardial band, and N-terminal pro-brain natriuretic peptide) (p < 0.01) were observed 2 h after completion of cycling but no changes in systolic (including strain-analyses) or diastolic cardiac function were observed at rest. O₂max was significantly lower at the 28 h time point than at baseline (p < 0.02). Plasma concentrations of total- (p < 0.01) and low-density lipoprotein-cholesterol (p < 0.01) were markedly lower after exercise. Systolic blood pressure was unchanged, but diastolic pressure was significantly lower after exercise than at baseline.

Conclusions: The results suggest that repeated moderate intensity exercise in elderly men was associated with a transient increase in cardiac biomarkers while cardiac function remained unaltered. A favorable reduction in blood lipids and diastolic blood pressure were seen for >28 h after the end of activity. An unexplained symptomless severe plasma hyponatremia developed in 3 of 6 subjects 28 h after the end of activity.

KEYWORDS:

• Master athletes
• long-distance cycling
• echocardiography
• blood pressure
• blood lipids

Acknowledgments

Support for the bicycle trip was provided by Maribo Medico A/S, Toms Gruppen A/S, and Orkla Health. This work was supported by the Lundbeck Foundation (grant R0-A975) and by the Danish Council for Independent Research, Natural Sciences (grant 10-084565). The skilled technical assistance of Thomas Nyegaard Beck, Regitze KraunsØe and Jeppe Bach are gratefully acknowledged.

Declaration of interest

The authors have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article. The Physician and Sportsmedicine peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This manuscript was funded by the Lundbeck Foundation [grant R0-A975] and by the Danish Council for Independent Research [grant 10-084565].