Exhaled nitric oxide and exercise in stable COPD patients.
OBJECTIVE
To evaluate exhaled nitric oxide (eNO) during exercise in patients with stable COPD.


METHODS
Outpatient evaluation in a rehabilitation center.


METHODS
Eleven consecutive male patients with stable COPD (age, 65 +/- 6 years; FEV(1), 56 +/- 10% predicted). Eight healthy (six men; age, 51 +/- 16 years) nonsmoking, nonatopic volunteers served as control subjects.


METHODS
In each subject, a symptom-limited cycle ergometry test was performed by monitoring eNO with the tidal-breath method to assess eNO concentration (FENO) and output (VNO) at rest, peak exercise, and recovery time.


RESULTS
Resting FENO (9.8 +/- 5.1 and 14.1 +/- 6.3 parts per billion, respectively) and VNO (4.2 +/- 2.0 and 5.9 +/- 3.4 nmol/min, respectively) were lower, although not significantly, in COPD patients than in control subjects. In both groups, FENO significantly decreased whereas VNO significantly increased during exercise. Both variables returned to baseline during the recovery time. Peak exercise VNO, but not FENO, was significantly lower in COPD patients than in control subjects (7.9 +/- 5.4 and 12.7 +/- 6.0 nmol/min, respectively, p < 0.05). The rise in VNO was weakly correlated to oxygen consumption VO(2)) both in control subjects (r = 0.31, p = 0. 002) and in COPD patients (r = 0.22, p = 0.03). FENO showed an inverse correlation to VO(2) in both groups (r = -0.53, p = 0.000; r = -0.31, p = 0.003 in control subjects and COPD patients, respectively).


CONCLUSIONS
In patients with mild and moderate COPD, eNO during exercise parallels that observed in normal control subjects. VNO, but not FENO, is significantly reduced at peak exercise in COPD patients as compared with control subjects. The long-term effects of exercise training on eNO has to be evaluated by further studies.
Clini
E
E
Pulmonary Division, Lung Function Unit, Fondazione S. Maugeri IRCCS, Gussago (Brescia), Italy. fsm.g2@numerica.it
Bianchi
L
L
Vitacca
M
M
Porta
R
R
Foglio
K
K
Ambrosino
N
N
D000328:Adult; D000368:Aged; D001944:Breath Tests; D005080:Exercise Test; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000502:physiology; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology*; D012016:Reference Values
D018836:Inflammation Mediators; D009569:Nitric Oxide