EFFECT OF HEART-FAILURE AND PHYSICAL-TRAINING ON THE ACUTE VENTILATORY RESPONSE TO HYPOXIA AT REST AND DURING EXERCISE

Citation
Cw. Barlow et al., EFFECT OF HEART-FAILURE AND PHYSICAL-TRAINING ON THE ACUTE VENTILATORY RESPONSE TO HYPOXIA AT REST AND DURING EXERCISE, Respiration, 64(2), 1997, pp. 131-137
Citations number
26
Categorie Soggetti
Respiratory System
Journal title
ISSN journal
00257931
Volume
64
Issue
2
Year of publication
1997
Pages
131 - 137
Database
ISI
SICI code
0025-7931(1997)64:2<131:EOHAPO>2.0.ZU;2-I
Abstract
We studied the acute ventilatory response to hypoxia (AHVR) in 10 pati ents with chronic heart failure (CHF) and in 10 subjects with normal l eft ventricular function (NLVF) before and after 8 weeks of home-based physical training. Subjects were studied at rest and during constant cycle exercise at a work rate equivalent to 40% of their maximum oxyge n consumption. The AHVR was not significantly different between the pa tients with CHF and those with NLVF either at rest (1.32 +/- 0.19 vs. 1.63 +/- 0.20 litres/min/% arterial desaturation; mean +/- SE) or duri ng constant light exercise (2.37 +/- 0.48 vs. 2.86 +/- 0.55 litres/min /% arterial desaturation). Both groups showed evidence of improved phy sical fitness after training with increases in maximum oxygen consumpt ion of 11 +/- 2.7% (p < 0.01) for the group with NLVF and of 8 +/- 3.2 % (p < 0.05) for the group with CHF. Values for the AHVR in the traine d state were not significantly different between the patients with CHF and those with NLVF either at rest (1.23 +/- 0.24 vs. 1.63 +/- 0.22 l itres/min/% arterial desaturation) or during constant light exercise ( 2.52 +/- 0.69 vs. 2.24 +/- 0.37 litres/min/% arterial desaturation). M oreover, these responses did not differ from those in the untrained st ate (see above). The AHVR increased during exercise compared with rest in both groups (p < 0.05). The AHVR is not substantially altered in p atients with CHF compared to subjects with NLVF. Physical training may reduce ventilation during exercise, but it has relatively little or n o effect on the AHVR. However, exercise increases the AHVR in patients with CHF, as it does in normals.