the exercise endurance
time, Borg dyspnea ratings at the isotime near end-exercise,
and IC are very reproducible indices [5], and that
Table 2 Correlations of the BDI score with airflow limitation and static hyperinflation
Spearman’s rank correlation coefficients Pearson’s correlation coefficient
Rs p value R p value
Dyspnea vs. Airflow limitation
BDI score vs. FEV1 (L) 0.60 < 0.0001 0.60 < 0.0001
BDI score vs. FEV1 (%pred) 0.56 < 0.0001 0.57 < 0.0001
BDI score vs. FEV1/FVC 0.56 < 0.0001 0.57 < 0.0001
Dyspnea vs. Static Hyperinflation
BDI score vs. IC (L) 0.45 < 0.0001 0.48 < 0.0001
BDI score vs. IC/predicted TLC 0.46 < 0.0001 0.51 < 0.0001
BDI score vs. IC/TLC 0.47 < 0.0001 0.48 < 0.0001
Table 3 Results of stepwise multiple regression analyses
to identify those variables that best predicted dyspnea
assessed by the BDI score
BDI score
Independent variables
Age (years) -
Smoking (pack-years) -
BMI (kg/m2
) -
FEV1 (L) 0.262
IC/predicted TLC -
DLCO (mL/min/mmHg) 0.144
PaO2 (mmHg) -
BNP (pg/mL) -
Cumulative R2 0.406
Nishimura et al. Respiratory Research 2011, 12:135
http://respiratory-research.com/content/12/1/135
Page 4 of 7
500 micrograms of nebulized ipratropium bromide can
improve the exercise endurance time by 32% on average.
This improvement correlated best with the IC improvement,
but not with the FVC or FEV1 improvements, and
the change in the Borg dyspnea ratings at the isotime
near end-exercise also correlated well with the IC
improvement [6]. An increased IC means reduced resting
lung hyperinflation. Using a similar mechanism, the
use of tiotropium bromide, salmeterol, or a fluticasone
propionate/salmeterol combination was associated with
sustained reductions in lung hyperinflation at rest and
during exercise. The resultant increases in inspiratory
capacity permitted a greater expansion of the tidal
volume, and contributed to improvements in both exercise
endurance and exertional dyspnea