Table 1 Suggested target values for key cardiopulmonary exercise testing variables (cycle ergometry) [1, 5,6,7, 10, 11, 15]

Peak \({\dot{\text{V}}\text{O}}_{2}\) (exercise capacity)

 ≥ 85% based on \({\dot{\text{V}}\text{O}}_{2}\) pred. or > 20 mL O₂/min/kg

 < 85%/ < 70%/ < 50% (mild/moderate/severe)

\({\dot{\text{V}}\text{O}}_{2}\)/WR (aerobic capacity)

≥ 9–10 mL/min/watt¹

 ≤ 8 mL/min/watt

\({\dot{\text{V}}\text{O}}_{2}\) at AT

 ≥ 40–80% pred. \({\dot{\text{V}}\text{O}}\) (usually 50–65% of peak \({\dot{\text{V}}\text{O}}_{2}\))

 < 40%/ < 30%/ < 25% (mild/moderate/severe)

Blood pressure

Increase by 10 mmHg per 30 watts

Decrease, inadequate increase

O₂ pulse (\({\dot{\text{V}}\text{O}}_{2}\)/HR)²

≥ 80%

< 70% pred. during peak exercise

Heart rate reserve (HRR)

≥ 85% pred. (< 15 bpm)

< 85% predicted (but wide range)

Breathing reserve (BR)

≥ 15–20% (or ≥ 11–15 L/min)

< 15–20% (or < 11–15 L/min)

Breathing frequency (BF)

≤ 50/min

≥ 60/min

EqCO₂ at AT

25–30 at AT, ≤ 40 after AT

≥ 35 at AT, > 40 after AT;

EqO₂ at AT

20–30 at AT, ≤ 40 after AT

≥ 35 at AT, > 40 after AT

\({\dot{\text{V}}\text{E}}/{\dot{\text{V}}\text{CO}}_{2}\) slope

25–30 (slightly lower than EqCO₂ at AT)

≥ 35 or < 20

RER

≥ 1.05 (ill) or ≥ 1.1 (healthy); > 1.1–1.5 in recovery phase; at rest: > 0.7, < 1.0

< 1 (peak exercise)

PETCO₂ (≈ PACO₂ ≈ PaCO₂)

> 35 mmHg (at rest); > 40 mmHg (during exercise)

 < 33 mmHg (at rest), < 3 mmHg increase or > 50 mmHg (peak exercise)

PETO₂ (≈ PAO₂)

 ≥ 90 mmHg (at rest), 20–30 mmHg increase during exercise

Lack of increase or decrease during exercise

P(A-a) O₂³

20 mmHg (at rest); 30 mmHg (during exercise)

> 35 mmHg

P(a-ET) CO₂⁴

At rest: minimally positive; during exercise: slightly negative

> 5 mmHg