Int J Sports Med 2005; 26(6): 426-431
DOI: 10.1055/s-2004-821113
Physiology & Biochemistry

© Georg Thieme Verlag KG Stuttgart · New York

Cardiovascular Responses to Apnea during Dynamic Exercise

U. Hoffmann1 , M. Smerecnik1 , D. Leyk1 , D. Essfeld1
  • 1Department of Physiology and Anatomy, Deutsche Sporthochschule Köln, Cologne, Germany
Further Information

Publication History

Accepted after revision: May 20, 2004

Publication Date:
10 September 2004 (online)

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Abstract

Breath holding maneuvers induce hypoxia, hypercapnia, and various cardiovascular responses typically including increases in total peripheral resistance, mean arterial pressure (MAP) and decreases in heart rate (HR). During dynamic exercise these responses may have a generally negative impact on performance. Moreover, they deserve particular attention in cardiovascular risk subjects. In 26 healthy sport students we studied the HR and MAP effects induced by the combination of dynamic exercise (cycle ergometry, 30 W and 250 W) with 20 s of either respiratory arrest (mouth piece pressure held constant at 20 mm Hg), free breathing, or rebreathing, i. e. periods of unimpeded breathing leading to similar levels of hypercapnia and hypoxia as the respiratory arrest. The measurements yielded no major differences between the conditions of rebreathing and free breathing. In contrast, 20 s of apnea led to a marked increase in MAP and a HR depression at both levels of exercise intensity. Additionally, there was a delayed MAP recovery after this stimulus. The present findings show that breath holding has marked effects on MAP and HR during dynamic exercise, which are essentially independent of the resulting hypoxia and of increases in intrathoracic pressure. The key factor seems to be an increase in total peripheral resistance, probably including a vasoconstriction in the exercising muscles.

References

Dr. Uwe Hoffmann

Deutsche Sporthochschule Cologne

Carl-Diem-Weg 6

50933 Cologne

Germany

Phone: + 4922149822910

Fax: + 49 2 21 49 82 67 90

Email: hoffmann@dshs-koeln.de