Journal
PHYSIOLOGY & BEHAVIOR
Volume 142, Issue -, Pages 97-103Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.physbeh.2015.02.007
Keywords
Trisomy 21; Epinephrine; Norepinephrine; Heart rate; Physical exercise; Chronotropic incompetence
Categories
Funding
- Lejeune Foundation (Paris-France)
- 'Association francaise de recherches sur la trisomie' (AFRT, Paris-France)
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Objective: Our purpose was to analyse if catecholamine responses to exercise would be different in Down syndrome (DS) with or without chronotropic incompetence. Research design and methods: Twenty five men with DS (mean age 22.2 +/- 3.2) and twenty six controls (CONT, mean age 22.5 +/- 1.4) participated in the study, and are divided into 3 groups: CONT, DS with chronotropic incompetence (DS +) and DS without chronotropic incompetence (DS). During two treadmill incremental tests, blood samples were collected for the determination of hormonal and metabolic variables. Results: Ten out of 25 DS had chronotropic incompetence whereas no CONT. At rest, compared to CONT, despite similar physical activity, DS with chronotropic incompetence had significantly higher subcutaneous fat mass (p < 0.001), lower epinephrine concentration (p < 0.01), and higher leptin (p < 0.01) and insulin concentrations (p < 0.05). At peak exercise, all DS had lower heart rate, oxygen uptake and blood lactate concentrations than controls (p < 0.001). During a 'Submaximal incremental test', DS with chronotropic incompetence had lower HR and lactate values (p < 0.001) compared to CONT and DS without chronotropic incompetence (p < 0.01). They also had blunted epinephrine and impaired norepinephrine responses to exercise compared to DS without chronotropic incompetence and CONT (p < 0.01 and p < 0.05 respectively). Conclusions: Our results indicate that catecholamine adaptations to exercise are not adequate in DS+ and are associated with exercise intolerance. Thus, this endocrine profile at rest and during exercise may limit endurance performance of DS. (C) 2015 Elsevier Inc. All rights reserved.
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