Re: The Impact of Excessive Endurance Exercise. Authors Reply

We would like to thank Dr Fox for his comments. The studies mentioned are population cohort studies looking at a wide range of individuals with varying activity and fitness levels. The Taiwan study[1] attempted to define the minimal amount of exercise required and looked at all comers in a standard medical screening program. They did demonstrate that higher levels of moderate or vigorous activity conferred no additional health benefits and, thus, more of a reverse J-shaped curve than a U-shaped curve. Given the scope of this review, which focused on excessive endurance exercise, we have focused on those at the extreme end of these mortality curves. The other related articles in the April and May issues of the BCMJ may provide more insight into the specific benefits of exercise, since it is clear that moderate exercise is beneficial. The specific studies mentioned are all observational studies with inherent limitations. There are other similar studies not included in the scope of the review that demonstrate similar U-shaped curves or reverse J-shaped curves, but there appears to be a consistent signal that further benefit and potential harm may lie at the extreme end of exercise. To our knowledge, there are no randomized studies that directly compare differences in exercise modality on cardiovascular morbidity or mortality. Overall, our take-home message is that we know moderate and even high levels of exercise appear to show benefit, but the upper limit at which adverse cardiac effects occur is not known.
—Andrea K.Y. Lee, MD
—Andrew D. Krahn, MD


References

1.    Wen CP, Wai JP, Tsai MK, et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: A prospective cohort study. Lancet 2011;378(9798):1244-1253.

Andrea K.Y. Lee, MD, Andrew D. Krahn, MD, FRCPC, FCCS. Re: The Impact of Excessive Endurance Exercise. Authors Reply. BCMJ, Vol. 58, No. 7, September, 2016, Page(s) 364 - Letters.



Above is the information needed to cite this article in your paper or presentation. The International Committee of Medical Journal Editors (ICMJE) recommends the following citation style, which is the now nearly universally accepted citation style for scientific papers:
Halpern SD, Ubel PA, Caplan AL, Marion DW, Palmer AM, Schiding JK, et al. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002;347:284-7.

About the ICMJE and citation styles

The ICMJE is small group of editors of general medical journals who first met informally in Vancouver, British Columbia, in 1978 to establish guidelines for the format of manuscripts submitted to their journals. The group became known as the Vancouver Group. Its requirements for manuscripts, including formats for bibliographic references developed by the U.S. National Library of Medicine (NLM), were first published in 1979. The Vancouver Group expanded and evolved into the International Committee of Medical Journal Editors (ICMJE), which meets annually. The ICMJE created the Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals to help authors and editors create and distribute accurate, clear, easily accessible reports of biomedical studies.

An alternate version of ICMJE style is to additionally list the month an issue number, but since most journals use continuous pagination, the shorter form provides sufficient information to locate the reference. The NLM now lists all authors.

BCMJ standard citation style is a slight modification of the ICMJE/NLM style, as follows:

  • Only the first three authors are listed, followed by "et al."
  • There is no period after the journal name.
  • Page numbers are not abbreviated.


For more information on the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals, visit www.icmje.org

BCMJ Guidelines for Authors

Leave a Reply