IJCA-18478; No of Pages 2 International Journal of Cardiology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Strenuous exercise and the heart: Are we not seeing the wood for the trees? Fabian Sanchis-Gomar a,⁎, Helios Pareja-Galeano a, Alejandro Santos-Lozano b,c, Carmen Fiuza-Luces c,d, Nuria Garatachea c,e, Alejandro Lucia c,d a
Department of Physiology, University of Valencia and Fundación Investigación Hospital Clínico Universitario/INCLIVA, Valencia, Spain Department of Biomedical Sciences, University of León, León, Spain Research Institute of Hospital 12 de Octubre (“i + 12”), Madrid, Spain d European University, Madrid, Spain e Faculty of Health and Sport Sciences, University of Zaragoza, Huesca, Spain b c
a r t i c l e
i n f o
Article history: Received 17 June 2014 Accepted 27 July 2014 Available online xxxx Keywords: Strenuous exercise Heart Atrial fibrillation Longevity Mortality
To the Editor, The health benefits of regular moderate-intensity physical activity (e.g. brisk walking, jogging) are well established and include, among others, a lower risk of all-cause mortality and cardiovascular disease (CVD). Yet whether such benefits, especially with regard to CVD, are also conferred by higher exercise levels is a matter of growing controversy in the medical literature. For instance, Guash and Mont recently expressed understandable concern about the link between regular strenuous endurance exercise (e.g. marathon running) and a higher risk of atrial fibrillation (AF) or other cardiac alterations (ventricular arrhythmias, ischemic damage), and how this might impact mortality rates [1]. Two recent studies have in fact detected an association between daily strenuous physical activity and a higher risk of AF and CVD-mortality [2,3]. However, while sharing some of the views of Guash and Mont as well as those of many cardiologists who are worried about the potentially harmful effects of prolonged strenuous exercise, we believe much discussion is needed.
⁎ Corresponding author at: Department of Physiology, Faculty of Medicine, University of Valencia, Av. Blasco Ibañez, 15, Valencia, 46010 Spain. E-mail address: [email protected] (F. Sanchis-Gomar).
The correlation between an elevated AF risk and endurance exercise is certainly a topic deserving attention. The first author of this letter (F.S.-G.), a physician himself, was a competitive endurance cyclist for 10 years. As a consequence, he suffered atrial dilatation and a first episode of paroxysmal AF early in life, at the age of 26. After 5 years of recurrent episodes, pulmonary vein isolation by trans-venous cryoablation seemed to be the only successful treatment. Although he has suffered no more AF episodes since then, high-intensity exercise is obviously no longer advisable, and this has deteriorated his own perception of well-being. Yet whether well-medically-controlled AF negatively impacts survival rates in former athletes, remains to be shown and more mechanistic research is needed. In fact, in a study recently reported in this journal, Brugger et al. showed that left atrial anatomical and electrical remodeling caused by a lifetime of endurance running does not have a negative impact on atrial mechanical function, ruling out AF as an exercise-induced cardiac change [4]. A cause–effect relationship between long-term regular exercise and cardiac alterations other than AF has not been clearly proven in humans. Moreover, provocative murine data showing cardiac remodeling after long-standing forced treadmill training cannot be extrapolated to athletes [5]. Kim et al. estimated the incidence of sudden death among U.S. marathoners over the period 2000–2010 [6], and showed that of 10.9 millions runners, only 59 (51 men) suffered cardiac arrest, with underlying CVD accounting for the majority of events. Also, mainly middle-aged, poorly trained men were in the high-risk group. If lifelong, prolonged, intense training was responsible for these catastrophic events, then a much greater proportion of the high-risk group would have been comprised of individuals with longer and more intense training histories. Of note, even a centenarian, Fauja Singh, recently completed a marathon race with no occurrence of cardiac problems [7]. To determine whether the health benefits of exercise are actually restricted to non-competitive, moderate (or recreational) exercise is of broad medical interest and will provide clinicians with more evidence-based data. In a recently published meta-analysis of cohort studies, we compared mortality rates in elite/professional athletes and the general population [8]. The data analyzed corresponded to 42,807 athletes (707 women) including Olympic-class marathoners or Tour de France participants. Its results might be surprising for many, and provocative for most: the all-cause pooled standard mortality ratio (SMR)
http://dx.doi.org/10.1016/j.ijcard.2014.07.159 0167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article as: Sanchis-Gomar F, et al, Strenuous exercise and the heart: Are we not seeing the wood for the trees?, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.07.159
2
F. Sanchis-Gomar et al. / International Journal of Cardiology xxx (2014) xxx–xxx
in athletes compared to the reference population was 0.67 (95% CI: 0.55–0.81; P b 0.001) and, when only CVD was considered as a cause of mortality, the pooled-SMR was 0.73 (95% CI: 0.65–0.82; P b 0.001). We are well aware of the fact that lifelong competitive exercise can increase the risk of musculoskeletal/connective tissue diseases, yet at present there is no evidence that this affects survival rates. In a world full of cardiovascular diseases (CVD), it is difficult to see the wood for the trees and all the observed multi-system, largely dose-dependent benefits of endurance exercise seem to be ignored [9]. However, evidence starts to mount against the notion that exercise benefits are confined to ‘moderate’ doses, at least in terms of total exercise time, and higher moderate physical exercise (e.g., brisk walking, jogging) levels (≥450 min/week), clearly above the minimum international recommendations of 150 min/week, have been associated with a longer life expectancy [10]. Endurance exercise has a restoring effect on an important risk factor for CVD, endothelial dysfunction [9]. Besides improving angiogenesis and endothelial health, exercise induces macrophage-mediated reverse cholesterol transport and has a beneficial, dose–response effect in attenuating aging autonomic system dysfunction, with trained elderly individuals showing similar baroreflex function to their moderately active younger peers [9]. Heart rate variability (HRV), a marker of autonomic function and a powerful predictor of CVD outcome (high HRV correlates with a better prognosis), is greater in former endurance athletes [11] as well as in veteran athletes with arrhythmias, compared with control patients [12]. Reduced angiotensin II, increased NO• and mainly improved vagal modulation and decreased sympathetic tone have all been implicated in the beneficial exercise effects on HRV [9]. While recognizing the potential dangers of competitive sports, we believe a more holistic point of view is warranted: the numerous
benefits of exercise, even at the highest intensity level, seem to outweigh its negative effects. Conflicts of interest The authors declare no conflicts of interest. References [1] Guasch E, Mont L. Exercise and the heart: unmasking Mr Hyde. Heart 2014;100: 999–1000. [2] Drca N, Wolk A, Jensen-Urstad M, Larsson SC. Atrial fibrillation is associated with different levels of physical activity levels at different ages in men. Heart 2014;100:1037–42. [3] Mons U, Hahmann H, Brenner H. A reverse J-shaped association of leisure time physical activity with prognosis in patients with stable coronary heart disease: evidence from a large cohort with repeated measurements. Heart 2014;100:1043–9. [4] Brugger N, Krause R, Carlen F, et al. Effect of lifetime endurance training on left atrial mechanical function and on the risk of atrial fibrillation. Int J Cardiol 2014;170: 419–25. [5] Ruiz JR, Joyner M, Lucia A. CrossTalk opposing view: prolonged intense exercise does not lead to cardiac damage. J Physiol 2013;591:4943–5. [6] Kim JH, Malhotra R, Chiampas G, et al. Cardiac arrest during long-distance running races. N Engl J Med 2012;366:130–40. [7] Sanchis-Gomar F, Pareja-Galeano H, Lucia A. ‘Olympic’ centenarians: are they just biologically exceptional? Int J Cardiol 2014;175:216–7. [8] Garatachea N, Santos-Lozano A, Sanchis-Gomar F, et al. Elite athletes live longer than the general population: a meta-analysis. Mayo Clin Proc 2014. [9] Fiuza-Luces C, Garatachea N, Berger NA, Lucia A. Exercise is the real polypill. Physiology (Bethesda) 2013;28:330–58. [10] Moore SC, Patel AV, Matthews CE, et al. Leisure time physical activity of moderate to vigorous intensity and mortality: a large pooled cohort analysis. PLoS Med 2012;9: e1001335. [11] Zaniqueli D, Morra EA, Dantas EM, et al. Heart rate at 4 s after the onset of exercise in endurance-trained men. Can J Physiol Pharmacol 2014;92:476–80. [12] Jensen-Urstad K, Bouvier F, Saltin B, Jensen-Urstad M. High prevalence of arrhythmias in elderly male athletes with a lifelong history of regular strenuous exercise. Heart 1998;79:161–4.
Please cite this article as: Sanchis-Gomar F, et al, Strenuous exercise and the heart: Are we not seeing the wood for the trees?, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.07.159
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Strenuous exercise and the heart: Are we not seeing the wood for the trees? Fabian Sanchis-Gomar a,⁎, Helios Pareja-Galeano a, Alejandro Santos-Lozano b,c, Carmen Fiuza-Luces c,d, Nuria Garatachea c,e, Alejandro Lucia c,d a
Department of Physiology, University of Valencia and Fundación Investigación Hospital Clínico Universitario/INCLIVA, Valencia, Spain Department of Biomedical Sciences, University of León, León, Spain Research Institute of Hospital 12 de Octubre (“i + 12”), Madrid, Spain d European University, Madrid, Spain e Faculty of Health and Sport Sciences, University of Zaragoza, Huesca, Spain b c
a r t i c l e
i n f o
Article history: Received 17 June 2014 Accepted 27 July 2014 Available online xxxx Keywords: Strenuous exercise Heart Atrial fibrillation Longevity Mortality
To the Editor, The health benefits of regular moderate-intensity physical activity (e.g. brisk walking, jogging) are well established and include, among others, a lower risk of all-cause mortality and cardiovascular disease (CVD). Yet whether such benefits, especially with regard to CVD, are also conferred by higher exercise levels is a matter of growing controversy in the medical literature. For instance, Guash and Mont recently expressed understandable concern about the link between regular strenuous endurance exercise (e.g. marathon running) and a higher risk of atrial fibrillation (AF) or other cardiac alterations (ventricular arrhythmias, ischemic damage), and how this might impact mortality rates [1]. Two recent studies have in fact detected an association between daily strenuous physical activity and a higher risk of AF and CVD-mortality [2,3]. However, while sharing some of the views of Guash and Mont as well as those of many cardiologists who are worried about the potentially harmful effects of prolonged strenuous exercise, we believe much discussion is needed.
⁎ Corresponding author at: Department of Physiology, Faculty of Medicine, University of Valencia, Av. Blasco Ibañez, 15, Valencia, 46010 Spain. E-mail address: [email protected] (F. Sanchis-Gomar).
The correlation between an elevated AF risk and endurance exercise is certainly a topic deserving attention. The first author of this letter (F.S.-G.), a physician himself, was a competitive endurance cyclist for 10 years. As a consequence, he suffered atrial dilatation and a first episode of paroxysmal AF early in life, at the age of 26. After 5 years of recurrent episodes, pulmonary vein isolation by trans-venous cryoablation seemed to be the only successful treatment. Although he has suffered no more AF episodes since then, high-intensity exercise is obviously no longer advisable, and this has deteriorated his own perception of well-being. Yet whether well-medically-controlled AF negatively impacts survival rates in former athletes, remains to be shown and more mechanistic research is needed. In fact, in a study recently reported in this journal, Brugger et al. showed that left atrial anatomical and electrical remodeling caused by a lifetime of endurance running does not have a negative impact on atrial mechanical function, ruling out AF as an exercise-induced cardiac change [4]. A cause–effect relationship between long-term regular exercise and cardiac alterations other than AF has not been clearly proven in humans. Moreover, provocative murine data showing cardiac remodeling after long-standing forced treadmill training cannot be extrapolated to athletes [5]. Kim et al. estimated the incidence of sudden death among U.S. marathoners over the period 2000–2010 [6], and showed that of 10.9 millions runners, only 59 (51 men) suffered cardiac arrest, with underlying CVD accounting for the majority of events. Also, mainly middle-aged, poorly trained men were in the high-risk group. If lifelong, prolonged, intense training was responsible for these catastrophic events, then a much greater proportion of the high-risk group would have been comprised of individuals with longer and more intense training histories. Of note, even a centenarian, Fauja Singh, recently completed a marathon race with no occurrence of cardiac problems [7]. To determine whether the health benefits of exercise are actually restricted to non-competitive, moderate (or recreational) exercise is of broad medical interest and will provide clinicians with more evidence-based data. In a recently published meta-analysis of cohort studies, we compared mortality rates in elite/professional athletes and the general population [8]. The data analyzed corresponded to 42,807 athletes (707 women) including Olympic-class marathoners or Tour de France participants. Its results might be surprising for many, and provocative for most: the all-cause pooled standard mortality ratio (SMR)
http://dx.doi.org/10.1016/j.ijcard.2014.07.159 0167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article as: Sanchis-Gomar F, et al, Strenuous exercise and the heart: Are we not seeing the wood for the trees?, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.07.159
2
F. Sanchis-Gomar et al. / International Journal of Cardiology xxx (2014) xxx–xxx
in athletes compared to the reference population was 0.67 (95% CI: 0.55–0.81; P b 0.001) and, when only CVD was considered as a cause of mortality, the pooled-SMR was 0.73 (95% CI: 0.65–0.82; P b 0.001). We are well aware of the fact that lifelong competitive exercise can increase the risk of musculoskeletal/connective tissue diseases, yet at present there is no evidence that this affects survival rates. In a world full of cardiovascular diseases (CVD), it is difficult to see the wood for the trees and all the observed multi-system, largely dose-dependent benefits of endurance exercise seem to be ignored [9]. However, evidence starts to mount against the notion that exercise benefits are confined to ‘moderate’ doses, at least in terms of total exercise time, and higher moderate physical exercise (e.g., brisk walking, jogging) levels (≥450 min/week), clearly above the minimum international recommendations of 150 min/week, have been associated with a longer life expectancy [10]. Endurance exercise has a restoring effect on an important risk factor for CVD, endothelial dysfunction [9]. Besides improving angiogenesis and endothelial health, exercise induces macrophage-mediated reverse cholesterol transport and has a beneficial, dose–response effect in attenuating aging autonomic system dysfunction, with trained elderly individuals showing similar baroreflex function to their moderately active younger peers [9]. Heart rate variability (HRV), a marker of autonomic function and a powerful predictor of CVD outcome (high HRV correlates with a better prognosis), is greater in former endurance athletes [11] as well as in veteran athletes with arrhythmias, compared with control patients [12]. Reduced angiotensin II, increased NO• and mainly improved vagal modulation and decreased sympathetic tone have all been implicated in the beneficial exercise effects on HRV [9]. While recognizing the potential dangers of competitive sports, we believe a more holistic point of view is warranted: the numerous
benefits of exercise, even at the highest intensity level, seem to outweigh its negative effects. Conflicts of interest The authors declare no conflicts of interest. References [1] Guasch E, Mont L. Exercise and the heart: unmasking Mr Hyde. Heart 2014;100: 999–1000. [2] Drca N, Wolk A, Jensen-Urstad M, Larsson SC. Atrial fibrillation is associated with different levels of physical activity levels at different ages in men. Heart 2014;100:1037–42. [3] Mons U, Hahmann H, Brenner H. A reverse J-shaped association of leisure time physical activity with prognosis in patients with stable coronary heart disease: evidence from a large cohort with repeated measurements. Heart 2014;100:1043–9. [4] Brugger N, Krause R, Carlen F, et al. Effect of lifetime endurance training on left atrial mechanical function and on the risk of atrial fibrillation. Int J Cardiol 2014;170: 419–25. [5] Ruiz JR, Joyner M, Lucia A. CrossTalk opposing view: prolonged intense exercise does not lead to cardiac damage. J Physiol 2013;591:4943–5. [6] Kim JH, Malhotra R, Chiampas G, et al. Cardiac arrest during long-distance running races. N Engl J Med 2012;366:130–40. [7] Sanchis-Gomar F, Pareja-Galeano H, Lucia A. ‘Olympic’ centenarians: are they just biologically exceptional? Int J Cardiol 2014;175:216–7. [8] Garatachea N, Santos-Lozano A, Sanchis-Gomar F, et al. Elite athletes live longer than the general population: a meta-analysis. Mayo Clin Proc 2014. [9] Fiuza-Luces C, Garatachea N, Berger NA, Lucia A. Exercise is the real polypill. Physiology (Bethesda) 2013;28:330–58. [10] Moore SC, Patel AV, Matthews CE, et al. Leisure time physical activity of moderate to vigorous intensity and mortality: a large pooled cohort analysis. PLoS Med 2012;9: e1001335. [11] Zaniqueli D, Morra EA, Dantas EM, et al. Heart rate at 4 s after the onset of exercise in endurance-trained men. Can J Physiol Pharmacol 2014;92:476–80. [12] Jensen-Urstad K, Bouvier F, Saltin B, Jensen-Urstad M. High prevalence of arrhythmias in elderly male athletes with a lifelong history of regular strenuous exercise. Heart 1998;79:161–4.
Please cite this article as: Sanchis-Gomar F, et al, Strenuous exercise and the heart: Are we not seeing the wood for the trees?, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.07.159
