Journal of Clinical and Preventive Cardiology

LETTER TO EDITOR
Year
: 2017  |  Volume : 6  |  Issue : 2  |  Page : 81--82

Author's Response


Nitin Burkule 
 Department of Cardiology, Jupiter Hospital, Eastern Express Highway, Thane, Maharashtra, India

Correspondence Address:
Nitin Burkule
Jupiter Hospital, Eastern Express Highway, Thane - 400 606, Maharashtra
India




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


Full Text



Sir,

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 [1] by Schnohr et al. and these limitations are highlighted in the section [2] “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 [3],[4] 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.[3],[5] Similar results are seen in Mayo clinic study [6] of postmyocardial infarction patients and the studies [7],[8],[9] 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 [10] 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.[11],[12]

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.[13]

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.[14]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Schnohr P, O'Keefe JH, Marott JL, Lange P, Jensen GB. Dose of jogging and long-term mortality: The Copenhagen City Heart Study. J Am Coll Cardiol 2015;65:411-9.
2Burkule N. Marathon running for amateurs: Benefits and risks. J Clin Prev Cardiol 2016;5:113-24.
3Lee DC, Pate RR, Lavie CJ, Sui X, Church TS, Blair SN. Leisure-time running reduces all-cause and cardiovascular mortality risk. J Am Coll Cardiol 2014;64:472-81.
4Lee DC, Lavie CJ, Vedanthan R. Optimal dose of running for longevity: Is more better or worse? J Am Coll Cardiol 2015;65:420-2.
5Eijsvogels TM, Molossi S, Lee DC, Emery MS, Thompson PD. Exercise at the extremes: The amount of exercise to reduce cardiovascular events. J Am Coll Cardiol 2016;67:316-29.
6Williams PT, Thompson PD. Increased cardiovascular disease mortality associated with excessive exercise in heart attack survivors. Mayo Clin Proc 2014;89:1187-94.
7Siscovick DS, Weiss NS, Fletcher RH, Lasky T. The incidence of primary cardiac arrest during vigorous exercise. N Engl J Med 1984;311:874-7.
8Mittleman MA, Maclure M, Tofler GH, Sherwood JB, Goldberg RJ, Muller JE. Triggering of acute myocardial infarction by heavy physical exertion. Protection against triggering by regular exertion. Determinants of Myocardial Infarction Onset Study Investigators. N Engl J Med 1993;329:1677-83.
9Albert CM, Mittleman MA, Chae CU, Lee IM, Hennekens CH, Manson JE. Triggering of sudden death from cardiac causes by vigorous exertion. N Engl J Med 2000;343:1355-61.
10Breuckmann F, Möhlenkamp S, Nassenstein K, Lehmann N, Ladd S, Schmermund A, et al. Myocardial late gadolinium enhancement: Prevalence, pattern, and prognostic relevance in marathon runners. Radiology 2009;251:50-7.
11Andersen K, Farahmand B, Ahlbom A, Held C, Ljunghall S, Michaëlsson K, et al. Risk of arrhythmias in 52 755 long-distance cross-country skiers: A cohort study. Eur Heart J 2013;34:3624-31.
12Abdulla J, Nielsen JR. Is the risk of atrial fibrillation higher in athletes than in the general population? A systematic review and meta-analysis. Europace 2009;11:1156-9.
13Thompson PD, Funk EJ, Carleton RA, Sturner WQ. Incidence of death during jogging in Rhode Island from 1975 through 1980. JAMA 1982;247:2535-8.
14Richard Dawkins, Archaic homo sapiens. The Ancestor's Tale: A Pilgrimage to the Dawn of Life, publisher Houghton Mifflin USA;2004.