TABLE 2 ] .

Results of Cardiopulmonary Exercise Testing According to the Presence or Absence of SDB

Variable	No SDB (n = 134)	SDB (n = 64)	P Value
$\stackrel{.}{\text{V}}$o2peak, mL O2/kg/min	21.2 ± 7.2	16.3 ± 5.4	< .001
			< .001a
Calculated METs	6.1 ± 2.1	4.8 ± 1.6	< .001
$\stackrel{.}{\text{V}}$o2peak not adjusted for patient’s weight, mL O2/min	1,868 ± 785	1,615 ± 632	.017
			< .001a
$\stackrel{.}{\text{V}}$o2peak % predicted by age and sex	68 ± 20	58 ± 18	.001
			< .001a
$\stackrel{.}{\text{V}}$o2peak/peak heart rate, mL O2/beat	0.15 ± 0.04	0.14 ± 0.04	.004
Resting peripheral oxygen saturation, %	98 ± 3	98 ± 4	.74
Nadir peripheral oxygen saturation, %	98 ± 2	98 ± 2	.72
Respiratory exchange ratio at peak exercise	1.2 ± 0.1	1.2 ± 0.1	.13
Nadir $\stackrel{.}{\text{V}}$e/$\stackrel{.}{\text{V}}$co2	38 ± 5	38 ± 5	.91
Resting heart rate, beats/min	70 ± 12	70 ± 12	.89
Peak heart rate, beats/min	140 ± 28	121 ± 28	< .001
Rhythm during exercise testing
Sinus	121 (90)	53 (83)	.16
Paced	11 (8)	8 (13)	.44
Atrial fibrillation/flutter	3 (1)	5 (5)	.33

Data are presented as mean ± SD or No (%). SDB was defined as ODI ≥ 10 as measured by overnight oximetry. MET = metabolic equivalent; $\stackrel{.}{\text{V}}$co₂ = minute volume of CO₂ uptake in the lung; $\stackrel{.}{\text{V}}$e = minute ventilation; $\stackrel{.}{\text{V}}$o₂peak = peak oxygen consumption during exercise. See Table 1 legend for expansion of other abbreviations.

^aAdjusted for age, sex, BMI, β-blocker use, calcium channel antagonist use, rhythm during exercise testing, and history of coronary artery disease, COPD, diabetes mellitus.