In this article we will review the main health risks posed by mountain ultramarathons. For this we have analyzed the data that we have considered most interesting from different studies in terms of physiological variables and modification of them in the face of a very long effort in time.
Despite the large number of research on the consequences of extreme loads in other sports, there is limited information on sustained intensity and physiological demands during mountain ultramarathons. (Fornasiero et al., 2018)
First of all, we found interesting the comparison made in the study “Race predictors and hemodynamic alteration after an ultra-trail marathon race” (Taksaudom et al., 2017) between finalizers and non-finalizers of a 66 km ultratrail. In the test, finalizers had lower FC at the start of the race and lower blood pressure than non-finalizers, as well as better maximum oxygen consumption and higher systolic volume. We can assume that these differences are important when taking on such a race and being able to finish it. The authors also assume that training factors are more important than anthropometric ones.
|Variables||Finalizers (n-189)||Non-finalizers (no. 39)|
|VO2 max (L/min), mean – DT||44.4-3.9||41.4-1.8|
|PSS(mmHg), mean ? DT||135.3-14.8||136.7-21.2|
|PSD(mmHg), mean ? DT||78.1-9.8||82.6-12.7|
|FC (puls./min), average – DT||74.9-11.9||78.9-14.6|
|VS (mL), mean – DT||40.2-13.4||35.9-9.8|
On the other hand, by making a comparison of the systolic and diastolic pressure (PSS and PSD), heart rate (FC) and systolic volume (VS) that the finalizers had at the beginning of the race with the values they presented at the end of it we can appreciate an increase in FC and a drop in all others.
|Variables||Pre-race (no. 33)||Post-race (no. 33)|
As an explanation for these variations, the authors indicate that the decrease in volemia caused by sweating that occurs in the long distance, although the athlete hydrates, carries a physiological response that reduces systolic pressure. This in turn decreases the systolic volume and consequently increases the FC to maintain blood flow. The interesting fact would have been to be able to collect the values of these same variables for non-finalparticipants as they could give us an idea of why they decided not to go ahead with the race.
On the other hand, in a study conducted by the University of Verona on physiological profiles and performance predictors also in a mountain ultramarathon of 65 Km. (Fornasiero et al., 2018) concluded that the parameters associated with maximum oxygen consumption were decisive in predicting performance in the race.
They also established a directly proportional relationship between the hours spent completing an ultra and the age or percentage of fat and inversely proportional between the hours and the maximum oxygen consumption or the maximum power developed in W/Kg.
The average intensity in the ultratrail of 65 km. was 77% of the FCmax. and for most of the running time the runners remained below the first vent threshold (HR-VT1). Through this data they held the idea that HR-VT1 represents a good delimiter of tolerable intensity for amateur runners in ultra mountain marathons of more than 10 hours. (Fornasiero et al., 2018)
At the University of Milan a study was also carried out that analyzed changes in lung function in a mountain ultramarathon, this time much harder: 330 km. and +24,000 m. cumulative ascent. The results were published in the Scandinavian journal Medical & Science in Sports showing a linear decrease in inspiring and expiratory reserve volumes. This, coupled with other variables, led them to conclude that lung function is affected throughout such a test. (Vernillo et al., 2015)
For their part, Seedhouse, Walsh, & Blaber (2006) related this linear regression to lung capacity (life capacity and maximum breathed volume in a second) directly to the duration of the test and presented the probability that this dysfunction may favor the decline of O2 saturation in the blood.
As for possible brain damage, the University Hospital of Basel in Switzerland studied the effect of mountain ultramarathons on the diffusion of cerebrospinal fluid. Thus, they were able to observe a significant increase in their intercellular volume whose recovery to normal values could take up to 48-72h. They concluded that rapid changes in extracellular fluid can lead to a stroke. (Zanchi et al., 2017)
Finally, we would like to talk about Troponin T. According to the recommendations of the European Society of Cardiology and the Amercian College of Cardiology in 2000, troponin T (cTnT) and I levels are usable as a diagnostic method for acute myocardial infarction without elevation of the ST complex (Shave, Whyte, George, Gaze, & Collinson, 2005). To support this theory we also have the study conducted by Drs. Stefan James, Paul Amstrong, Robert Califf, Maarten L. Simoons, Per Venge, Lars Wallentin and Bertin Lindahl in 7115 patients with acute coronary syndrome without elevation of the ST complex. In the electrocardiograms it was concluded that patients with levels above 0.1 g/l of cTnT in the blood had a higher mortality rate in 30 days (5.5% )[201/3679] than those with levels of 0.1 g/l (2.2% [75/3436]). For a cut-off value of 0.03 g/l, the discrimination between high and low mortality risk was even higher: 5.1% (234/4552) versus 1.6% (42/2563). And even higher for a value of 0.01 g/l: 5.0% (254/5123) vs. 1.1% (22/1992). (James et al., 2003)
Moving this information to the sporting arena, and more specifically that of the long-distance race, data was collected from the London marathons of 2002 and 2003 and 72 runners aged 35-9 were studied. At the beginning of the race, they all had values less than 0.01 g/l of cTnT in their blood. After the end of the race, cTnT levels had risen above 0.01 g/l in 56 subjects (78%). Of these, 42 (58%) concentrations above 0.03 g/l, 26 (36%) 0.05 g/l and 8 (11%) greater than 0.1 g/l. There were no symptoms of ischemia in previously performed electrocardiograms. After the competition, the systolic function did not vary significantly but a reduction in systolic volume could be seen. Alterations in cTnT values could not be related to the age of participants. (Shave et al., 2005)
Connecting this two informations could perhaps be assessed an irrigation of acute myocardial infarction or at least coronary dysfunction in long-distance strokes in subjects with a high elevation of Troponin T in the blood.
It is also worth mentioning, in the thread of heart problems, the study of Vitiello and collaborators (2013) which concludes that running a mountain ultramarathon induces a transient ventricular dysfunction, associated in some subjects with an increase of troponin I ( cTnI) which is a biomarker of heart damage as indicated above according to recommendations of the European Society of Cardiology and the Amercian College of Cardiology.
By analyzing the above, we can deduce that there is a transient decrease in lung, cardiac and brain functions which can expose us, in some cases, to serious health risks. It would therefore be interesting to be able to count, prior to the efforts of the ultra distance in the mountains, with tests and medical analyses that allow us to rule out pathologies that increase these risks. Having regard to studies on troponin T, for example, it seems obvious to think that it would be appropriate to perform a stress test that will check the extent to which cTnT levels rise in the face of intense and prolonged exercise. On the other hand, we would have to analyze the influential variables in the duration or non-completion of the test such as age, percentage of fat, VO2max, blood pressure, FC and resting systolic volume and take them into account when enrolling in a race or train for her. And finally, once we are running the race, it is interesting the conclusion of Fornasiero and collaborators (2018) in which they establish the first ventthreshold as an indicative delimiter of the tolerable intensity that we can maintain for a race more than 10 hours. It is therefore very easy to calculate our first ventilatory threshold and try to stay below it throughout the race.
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Fornasiero, A., Savoldelli, A., Fruet, D., Boccia, G., Pellegrini, B., & Schena, F. (2018). Physiological intensity profile, exercise load and performance predictors of a 65-km mountain ultra-marathon. Journal of Sports Sciences, 36(11), 1287–1295. https://doi.org/10.1080/02640414.2017.1374707
James, S., Armstrong, P., Califf, R., Simoons, M. L., Venge, P., Wallentin, L., & Lindahl, B. (2003). Troponin T levels and risk of 30-day outcomes in patients with the acute coronary syndrome: Prospective verification in the GUSTO-IV trial. American Journal of Medicine, 115(3), 178–184. https://doi.org/10.1016/S0002-9343(03)00348-6
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Zanchi, D., Viallon, M., Goff, C. Le, Millet, G. P., Giardini, G., Croisille, P., & Haller, S. (2017). Extreme mountain ultra-marathon leads to acute but transient increase in cerebral water diffusivity and plasma biomarkers levels changes. Frontiers in Physiology, 7(JAN), 1–10. https://doi.org/10.3389/fphys.2016.00664