LETTER TO EDITOR
Year : 2017 | Volume
: 6 | Issue : 2 | Page : 81--82
Department of Cardiology, Jupiter Hospital, Eastern Express Highway, Thane, Maharashtra, India
Jupiter Hospital, Eastern Express Highway, Thane - 400 606, Maharashtra
|How to cite this article:|
Burkule N. Author's Response.J Clin Prev Cardiol 2017;6:81-82
|How to cite this URL:|
Burkule N. Author's Response. J Clin Prev Cardiol [serial online] 2017 [cited 2021 Mar 3 ];6:81-82
Available from: https://www.jcpconline.org/text.asp?2017/6/2/81/203528
We are very happy to note your interest in reading the article and appreciate your critical evaluation of the evidence and lacunae. In the wake of lay press highlighting the deaths of high profile individuals during running, the purpose of the paper was to give an unbiased presentation of high-quality literature about exercise and its effects in one place so that the keen readers can pursue further reference reading.
We agree with the lacunae in Copenhagen heart study  by Schnohr et al. and these limitations are highlighted in the section  “challenges of interpreting epidemiological studies of physical activity” and “The reverse J shape relationship of running and mortality.” In fact, these authors showed U-shaped relation (mortality of intense exercise equals to sedentary lifestyle) which many experts have rejected. However, in Cooper clinic study , of 55,137 adults, quartiles of running intensity groups (not predefined exercise level groups) were studied to have fairly equal number of participants in each group. There is very convincing reverse J-shaped relation for time, distance, speed, frequency, and metabolic equivalents min/week when examined separately., Similar results are seen in Mayo clinic study  of postmyocardial infarction patients and the studies ,, mentioned in “exercise paradox.” With many confounders in subjects of epidemiological studies, it is very unlikely that a direct cause and effect of strenuous physical activity and mortality can ever be demonstrated. However, there is a consistent signal that there is nonlinear relation of exercise “dose” and cardiovascular “benefit” in nonathlete population. Though the insights from the surrogate markers such as cardiac remodeling, biomarkers, and fibrosis  on imaging do not establish direct cause and effect, they do suggest a possible mechanistic link. The association of strenuous exercise and increased incidence of late-life atrial fibrillation is very convincing and robust enough than just another hypothesis.,
We agree with your statement “we can state that more may not necessarily be better.” However, we would also like to add caution of untoward effects of strenuous physical activity in sedentary people, in their middle age, who suddenly start training for Marathon events. Though the recorded cardiac event rates are very low during the Marathon event, there is no systematic record of cardiac event rates during training which may not be negligible.
We are grateful for pointing out the mistake about the evolutionary time frame of “Homo sapiens-Sapiens” (the subspecies of “Homo” which is the modern man). The “Homo sapiens-Sapiens” really arrived on the evolutionary stage around 200,000 years back. The “archaic homo sapiens” which include Homo habilis and Homo erectus (forefathers of Neanderthals and modern man) arrived 2,500,000 years (2.5 million) back.
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