The rise in obesity and associated metabolic diseases has increased public awareness of the benefits of physical activity. Among other factors, this may help explain the exponential growth in recreational participation in endurance sports. A marathon was once considered a formidable challenge, but for many amateur runners those 42 km now seem insufficient. Similarly, an Olympic-distance triathlon is increasingly viewed as accessible, and many people move directly to an Ironman: no less than a 3.8 km swim, 180 km of cycling and a 42 km run.
Although regular physical activity is associated with better short- and long-term health, prolonged and strenuous exercise can acutely raise blood biomarkers commonly used in clinical practice to diagnose disease. The stress imposed by an event of this kind has physiological consequences. After an Ironman, markers of inflammation, oxidative stress and DNA damage increase. In clinical practice, a higher biomarker value often indicates a more severe condition or disease, so it is plausible that post-ultra-endurance values could be associated with a risk of adverse long-term health consequences. The debate is whether the elevated biomarkers observed after ultra-endurance races reflect genuine pathological changes or normal physiological processes resulting from a transient adaptation 1.
To examine the acute effects and possible long-term implications of completing an Ironman on markers of cardiac, muscle, liver and kidney damage, a Swedish research group studied 30 triathletes (15 men and 15 women) 2 and assessed several blood parameters before the race (T1), immediately afterward (T2) and after one week of rest (T3).
Large acute increases were observed in the biomarkers after the race. These changes were more pronounced in men, indicating that women tolerated prolonged, stressful exercise better than men both immediately after the race and one week later.
Figure 1. Changes in blood biomarkers from before the Ironman (T1) to one week afterward (T3). Adapted from Danielsson, Tom, et al., 2017
Although the biomarkers returned to baseline after one week of rest, the stress placed on the body to complete an event of this magnitude should not be dismissed. Completing many ultra-endurance events each year may not benefit health. Based on the study findings, it would be advisable not to subject the body to repeated efforts of this kind within a short period. Good physical preparation and extensive experience in these sports are also essential before participating, and working with exercise specialists may be the best approach.
REFERENCES
- Ruiz, J. R., Joyner, M. & Lucia, A. CrossTalk opposing view: Prolonged intense exercise does not lead to cardiac damage. J. Physiol. 591, 4943–4945 (2013).
- Danielsson, T. et al. Blood biomarkers in male and female participants after an Ironman-distance triathlon. PLoS One 12, e0179324 (2017).
AUTHORS:
Graduate in Physical Activity and Sport Sciences, official master's degree in Integrative Physiology, university specialist in Personal Training, NSCA-CPT.
Website: www.fissac.com
Pedro Valenzuela
Researcher in the Physiology Unit at the University of Alcalá and the Performance Monitoring Unit at the Sports Medicine Center (AEPSAD, Madrid High Performance Center).
Website: www.fissac.com
