Crewther, Blair; Cook, Christian; Fitzgerald, John; Starczewski, Michal; Gorski, Michal; Orysiak, Joanna

Author(s)

Crewther, Blair

Cook, Christian

Fitzgerald, John

Starczewski, Michal

Gorski, Michal

Orysiak, Joanna

Publication Date

2020-11

Abstract

Purpose: Reported associations between vitamin 25(OH)D and exercise performance are equivocal, perhaps due to complex interplay with cortisol and testosterone. In this study, the authors investigated serum 25(OH)D and cortisol as moderators of the testosterone relationship with exercise performance in adolescent male athletes. Methods: A total of 88 ice hockey players were assessed for serum 25(OH)D, cortisol, testosterone, body composition, and exercise performance, based on countermovement jump power and muscle torque. The authors tested independent relationships, before examining complex interactions via moderated regression analyses. Results: Most athletes (62.5%) exhibited a suboptimal (20-30 ng·mL−1) serum 25(OH)D concentration, whereas 9.1% of athletes were deficient (<20 ng·mL−1). Serum 25(OH)D was not related to performance when controlling for testing year, age, and fat mass. Further modeling revealed a significant hormonal interaction. Specifically, in low-25(OH)D subjects, testosterone predicted countermovement jump power at a high (β = 7.10, effect size = .43, P < .01), but not low (β = −3.32, effect size = −.20, P = .09), cortisol concentration. Conclusions: Serum 25(OH)D was a poor predictor of exercise performance, but it did moderate (with cortisol) the testosterone link to muscle power. Notably, this relationship emerged among individuals with a 25(OH)D concentration (~22 ng·mL−1) approaching the deficiency cutoff. Viewing 25(OH)D as a moderating, rather than dose responsive, variable could help explain equivocal cross-sectional associations.

Citation

Pediatric Exercise Science, 32(4), p. 204-209

ISSN

1543-2920

0899-8493

Pubmed ID

32726751

Link

https://hdl.handle.net/1959.11/29162

Publisher

Human Kinetics, Inc

Title

Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes

Type of document

Journal Article

Entity Type

Publication

Author(s)	Crewther, Blair Cook, Christian Fitzgerald, John Starczewski, Michal Gorski, Michal Orysiak, Joanna
Publication Date	2020-11
Abstract	<p><b><i>Purpose:</i></b> Reported associations between vitamin 25(OH)D and exercise performance are equivocal, perhaps due to complex interplay with cortisol and testosterone. In this study, the authors investigated serum 25(OH)D and cortisol as moderators of the testosterone relationship with exercise performance in adolescent male athletes. <b><i>Methods:</i></b> A total of 88 ice hockey players were assessed for serum 25(OH)D, cortisol, testosterone, body composition, and exercise performance, based on countermovement jump power and muscle torque. The authors tested independent relationships, before examining complex interactions via moderated regression analyses. <b><i>Results:</i></b> Most athletes (62.5%) exhibited a suboptimal (20-30 ng·mL<sup>−1</sup>) serum 25(OH)D concentration, whereas 9.1% of athletes were deficient (<20 ng·mL<sup>−1</sup>). Serum 25(OH)D was not related to performance when controlling for testing year, age, and fat mass. Further modeling revealed a significant hormonal interaction. Specifically, in low-25(OH)D subjects, testosterone predicted countermovement jump power at a high (<i>β</i> = 7.10, effect size = .43, <i>P</i> < .01), but not low (<i>β</i> = −3.32, effect size = −.20, <i>P</i> = .09), cortisol concentration. <b><i>Conclusions:</i></b> Serum 25(OH)D was a poor predictor of exercise performance, but it did moderate (with cortisol) the testosterone link to muscle power. Notably, this relationship emerged among individuals with a 25(OH)D concentration (~22 ng·mL<sup>−1</sup>) approaching the deficiency cutoff. Viewing 25(OH)D as a moderating, rather than dose responsive, variable could help explain equivocal cross-sectional associations.</p>
Citation	Pediatric Exercise Science, 32(4), p. 204-209
ISSN	1543-2920 0899-8493
Pubmed ID	32726751
Link	https://hdl.handle.net/1959.11/29162
Publisher	Human Kinetics, Inc
Title	Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes
Type of document	Journal Article
Entity Type	Publication

Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes

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