Last Word on Point:Counterpoint: Estrogen and sex do/do not significantly influence post-exercise indexes of muscle damage, inflammation, and repair

Abstract

POINT-COUNTERPOINTLast Word on Point:Counterpoint: Estrogen and sex do/do not significantly influence post-exercise indexes of muscle damage, inflammation, and repairMonica J. Hubal and Priscilla M. ClarksonMonica J. Hubal and Priscilla M. ClarksonPublished Online:01 Mar 2009https://doi.org/10.1152/japplphysiol.00030.2009MoreSectionsPDF (28 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat to the editor:We thank those who contributed interesting and insightful ideas. We have consistently found in relatively large samples (over 100 subjects, where we were sufficiently powered to detect small differences between groups) that there was no difference between men and women in soreness response to muscle damaging exercise and that women had either an equal or greater strength loss postexercise (2, 5). Strength loss is considered a valid and reliable assessment of muscle damage. If estrogen protects women from exertional muscle damage, we would have found differences in these measures, given our sample size. In addition, we have tested several of these large cohorts for effects of oral contraceptive use and found little difference between users and non-users. Although studies of pre- versus post-menopausal women could provide insight into estrogenic effects in humans, we agree with several of the respondents that these studies would be confounded either by interindividual variability (cross-sectional design) or by age-related changes in muscle (longitudinal design). We have also not detected consistent sex differences in the frequency of men and women as “high responders” to eccentric exercise, likely due to the low frequency of high responders in the population. Moreover, a high response to eccentric exercise may be driven, at least in part, by genetic predisposition (1).The compelling data that Dr. Tiidus presents showing that estrogen is protective against exercise-induced muscle damage in rats is intriguing because of estrogen's protective effect in lowering heart disease risk in women. From these results, it might be suggested that estrogen could also protect skeletal muscle in women. However, women tend to show greater prevalence/risk of some disease-associated myopathies, such as statin-induced myopathy (albeit this could be due to body size) (4) and poly- and dermato-myositis (3). We agree that a good test to conclusively show that estrogen does not protect skeletal muscle of women when exposed to damaging exercise is to test a group of ovariectomized women in a longitudinal design. However, if estrogen served as a significant protector against skeletal muscle damage, we would have observed differences in muscle damage indicators between men and women in our research studies. If estrogenic effects were so minimal as not to be observed in our studies, we question their relevance.REFERENCES1 Clarkson PM, Hoffman EP, Zambraski E, Gordish-Dressman H, Kearns A, Hubal M, Harmon B, Devaney JM. ACTN3 and MLCK genotype associations with exertional muscle damage. J Appl Physiol 99: 564–569, 2005.Link | ISI | Google Scholar2 Hubal MJ, Rubinstein SR, Clarkson PM. Muscle function in men and women during maximal eccentric exercise. J Strength Cond Res 22: 1332–1338, 2008.Crossref | ISI | Google Scholar3 Mastaglia FL, Phillips BA. Idiopathic inflammatory myopathies: epidemiology, classification, and diagnostic criteria. Rheum Dis Clin North Am 28: 723–741, 2002.Crossref | ISI | Google Scholar4 Rosenson RS. Current overview of statin-induced myopathy. Am J Med 116: 408–416, 2004.Crossref | ISI | Google Scholar5 Sewright KA, Hubal MJ, Kearns A, Holbrook MT, Clarkson PM. Sex differences in response to maximal eccentric exercise. Med Sci Sports Exerc 40: 242–251, 2008.Crossref | PubMed | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: M. J. Hubal, Research Center for Genetic Medicine, Children's National Medical Center, 111 Michigan Ave, NW, Washington, DC 20010 (e-mail: [email protected]) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformationCited BySex Differences in Exercise-Induced Muscle Pain and Muscle DamageThe Journal of Pain, Vol. 13, No. 12 More from this issue > Volume 106Issue 3March 2009Pages 1022-1022 Copyright & PermissionsCopyright © 2009 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00030.2009History Published online 1 March 2009 Published in print 1 March 2009 Metrics