Attenuation of muscle metaboreflex in chronic obstructive pulmonary disease.
OBJECTIVE
Abnormal skeletal muscle function is well documented in chronic obstructive pulmonary disease, but there is no information about the activity of muscle metabosensitive afferents. In this study, we tested the hypothesis that patients with chronic obstructive pulmonary disease would have abnormal reflex responses to stimulation of metabosensitive afferents in skeletal muscle when compared with healthy, matched subjects.


METHODS
In 16 patients with moderate to severe chronic obstructive pulmonary disease and 13 healthy, age-matched control subjects, we evaluated heart rate, mean blood pressure, calf blood flow, and calf vascular resistance responses to static handgrip exercise at 30% of maximal voluntary contraction, followed by recovery with or without circulatory occlusion. Muscle metaboreflex control of calf vascular resistance was estimated by subtracting the area under the curve with circulatory occlusion from the area under the curve without circulatory occlusion.


RESULTS
Mean blood pressure and heart rate responses were not significantly different in patients and controls during exercise and recovery. In the control group, calf vascular resistance increased significantly during exercise and remained elevated above baseline during circulatory occlusion, whereas in patients changes from rest were not significantly different in both trials. Estimated muscle metaboreflex control of calf vascular resistance was significantly reduced in the patients (controls: 31 +/- 22 units, patients: 8 +/- 31 units, P < 0.05).


CONCLUSIONS
Patients with chronic obstructive pulmonary disease have a reduced calf vascular resistance response to handgrip exercise and to selective activation of muscle metaboreflex when compared with healthy subjects.
Roseguini
Bruno T
BT
Exercise Pathophysiology Research Laboratory, Hospital of Clinics of Porto Alegre, Porto Alegre, Brazil.
Alves
Cristiano N
CN
Chiappa
Gaspar R
GR
Stein
Ricardo
R
Knorst
Marli M
MM
Ribeiro
Jorge P
JP
D001794:Blood Pressure; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D008659:Metabolic Diseases / Q000503:physiopathology*; D008875:Middle Aged; D010477:Perfusion; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012129:Respiratory Function Tests; D018434:Sickness Impact Profile