Table 2

Isotime values of selected physiological and perceptual responses during high-intensity, constant work rate exercise after placebo or bronchodilators (n=12)

VariablesPlaceboBronchodilatorsP Value
Metabolic
Embedded Image (ml/min)
Exercise1107±3001180±3550.94
Δ exercise–rest808±128835±1410.86
Embedded ImageCO2 (ml/min)1110±2931221±3350.88
RER1.00±0.071.04±0.080.90
Ventilatory/gas exchange
Embedded ImageE (l/min)37.6±15.841.3±17.40.02
Embedded ImageE/MVV0.87±0.100.88±0.110.90
ƒ (respirations/min)31±431±50.95
VT (litres)1.24±0.461.34±0.500.02
IC (litres)
Exercise1.67±0.582.02 ± 0.650.02
Δ exercise–rest−0.29±0.18−0.25±0.200.78
IRV (litres)0.48±0.170.32±0.150.01
Spo2 (%)91±390±20.88
Cardiovascular
QT (l/min)
Exercise11.7±3.111.6±2.90.92
Δ exercise–est4.4±1.04.3±0.90.87
HR (bpm)
Exercise133±22134±240.68
Δ exercise–rest54±1852±140.74
SV (ml)
Exercise89±1888±160.81
Δ exercise–rest28±1526±190.75
Subjective
Dyspnoea scores8 (6–10)6 (4–8)0.03
Leg effort scores7 (4–9)5 (3–8)0.04
  • Values are means ± SD, with the exception of subjective variables (median and range).

  • bpm, beats per minute; ƒ, breathing frequency; HR, heart rate; IC, inspiratory capacity; IRV, inspiratory reserve volume; QT, cardiac output; RER, respiratory exchange rate; Spo2, oxygen saturation by pulse oximetry; SV, stroke volume;

    Formula
    , carbon dioxide output;
    Formula
    E, minute ventilation;
    Formula
    , oxygen uptake; VT, tidal volume.