According to certain scientific studies carried out on rats, the elderly who suffer from heart problems and with an athletic endurance "should curse" too much aerobic activity carried out during their life.
Athlete's Heart: Health or Illness?
An athlete's heart is characterized by better contractile skills, both in terms of efficiency and effectiveness. All this thanks to different adaptations: the muscle fibers (which contract to pump blood) are stronger and more elastic, the dimensions of the walls and cardiac cavities are greater, the valves open and close better, the overall volume is greater, coronary blood supply is higher (not due to branches but due to flow), muscle myosin has a greater ATPase activity and so on. Such adaptations translate into functional improvements that enhance the athletic and physical health of the athlete; they are: bradycardia (reduced heart rate), increased coronary reserve (increased response to heart oxygenation under stress), increased peripheral capillarization, venous return and arterial elasticity.
Recall that even athletes who practice strength and power undergo cardiac changes, but of a different nature. In this case only a thickening of the ventricular walls occurs, while the internal cavities remain unchanged.
Obviously, neither the first nor the second circumstance must be confused with primitive cardiomyopathies, among which, for example, dilatations (in which the cardiac cavity is abnormally magnified and creates significant imbalances) and hypertrophic (characterized by an abnormal thickening of the cardiac muscle without increasing pumping capacity, among these we recall the hypertrophy of the left ventricle, a frequent complication of the use of anabolic steroids for performance purposes).
Despite all these benefits, a certain increase in the probability of developing arrhythmias has been shown in elderly background athletes.
Some athletes have heart problems: why?
Assuming that they are former elite athletes, that is professionals who exploited immense loads and volumes of aerobic training for competitive purposes (cyclists, marathon runners, etc.), it seems that, having reached the third age, some of them suffer from cardiac dysfunctions.
In light of this suspicion, the researchers certainly did not wait. Endurance exercise: interferes with heart rhythm is the title of an advertisement on the well-known site "BBC.com" (in the news section), published May 13, 2014 and based on what was published on "PubMed" in the same period: " Excercise training reduces resting heart rate via downregulation of the funny canes HCN4 ". The authors are: D'Souza A, Bucchi A, Johnsen AB, Logantha SJ, Monfredi O, Yanni J, Prehar S, Hart G, Cartwright E, Wisloff U, Dobryznski H, DiFrancesco D, Morris GM, Boyett MR; the abstract mentions the following:
"Endurance athletes exhibit sinus bradycardia, ie a slow heart rhythm at rest, associated with a greater incidence of sinus node dysfunction (pacemakers) that require implantation of an electronic pacemaker in old age. These variations are therefore not attributable to changes in the autonomic nervous system, but rather to intrinsic electrophysiological changes of the natural pacemaker We have shown that induced bradycardia formation persists after blocking the autonomic nervous system in vivo in the mouse and in vitro with a denervated pacemaker. Ionic of the pacemaker, in particular of the regulation HCN4 (protein) and of the corresponding ionic current "If". The block of "If" abolishes the difference in the heart rate in trained and sedentary animals in vivo, and in vitro. We observe a downregulation of the Tbx3, an over-regulation of the NSRF and miR-1 induced by training, which explain l at down regulation of HCN4 proteins. These results justify the pathological potential of cardiac adaptation to exercise ".
In summary, the " British Heart Foundation " argues that, due to such molecular modifications, certain athletes may experience heart rhythm disturbances (such as arrhythmias) and need a pacemaker implant. On the other hand, the specialists also point out that: to date, the benefits of aerobic activity outweigh the risks, and that much research is still needed to better define the results.
In conclusion, the excess of aerobic activity continued for decades can be harmful; on the other hand, respecting some simple recommendations, aerobic activity is far from harmful. These are:
- Carry out 150 minutes (2 hours and 30 minutes) of aerobic activity per week with moderate intensity (obviously, this totally excludes the competitive activities and is contextualised in the health field)
- It is not necessary to perform only one or two long sessions; far from it! Better to divide the volume into more numerous and smaller sessions
- It is important to respect the recovery times between sessions; over-training can hit (and therefore weaken) even the strongest athletes
- Be sure to "warm up" the muscles and heart before intense exercise
- Always carry out appropriate fatigue and lengthening at the end of the session or in separate sessions.
Reference sites:
- BBC: www.bbc.com/news/healt-27389257
- PUBMED: //www.ncbi.nlm.nih.gov/pubmed/24825544.
