Variable Clinical usefulness Cutoffs/patterns of abnormality Metabolic Estimated lactate threshold (LT) (i) Prognosis in CHF [52 ] (i)
LT < 40% predicted
peak [2 ] (ii) Marker of disease severity in PAH [53 ] (ii) Influenced by age, gender, and fitness [4 , 7 , 42 , 76 ] (iii) Risk predictor of postoperatory complications in the elderly [50 , 51 ] (iv) Guide exercise training intensity [72 , 73 ] (v) Responsive to rehabilitation in less impaired patients with chronic cardiopulmonary diseases [54 , 70 ]
/
work rate (mL/min/W)(i) Indicative of impaired O2 delivery and/or utilization [77 –81 ] (i) <lower limit of normality (<8.5 mL/min/W) [4 , 8 ] (ii) Adjunct for the diagnosis of myocardial ischemia [82 –88 ] (ii) Decrease in slope (or plateau) as exercise progresses [77 –81 ]
efficiency slope (OUES)(i) Functional impairment and prognosis in CHF [18 , 89 –94 ] Mortality in CHF
1.05 L/min/log (L/min) or <65% predicted [89 ] (ii) Response to interventions in CHF [95 ] (iii) More sensitive to training than the
/
slope in CHF [96 ]
efficiency plateau (OUEP)Functional impairment and prognosis in CHF [89 ] Mortality in CHF
25 mL/L or <65% predicted [89 ] Ventilatory Excess exercise ventilation (i) Prognosis in PAH [97 , 98 ] and CHF, even under
-blocker therapy (CHF) [99 , 100 ] <age—and gender-specific lower limits of normality [10 , 11 ] (ii) Responsive to therapy in CHF [101 –103 ], PAH [104 , 105 ], and CTEPH [106 ] (iii) Responsive to exercise training [107 ] Mortality in CHF
/
≥ 34 [108 ]
≥ 45 [109 ] Mortality in PAH
/
≥ 52 [97 ]
LT ≥ 54 [98 ]
/
≥ 62 [98 ]
/
≥ 48 [97 ] Postoperative complications of lung resection
/
≥ 34 [110 ] End-tidal partial pressure for CO2 (
ET CO2 ) (i) Adjunct for the diagnosis of PVD [111 ] Diagnosis of PVD [111 ] (ii) Prognosis in CHF [112 –116 ] “likely” = ≤ 30 mmHg at the LT (iii) Marker of disease severity in PAH [97 , 111 , 117 , 118 ] “very likely” = ≤ 20 mmHg at the LT (iv) Diagnosis of a patent forame ovale in PAH [119 ] progressive reductions as exercise increases (v) Responsive to drug therapy in PAH[105 ] and CHF [101 ] sudden increase with exercise cessation (vi) Responsive to exercise training [120 ] Mortality in CHF ≤33 mmHg at rest [112 , 114 ] ≤36 mmHg at the LT [115 ] <31 mmHg at peak [116 ] Exertional oscillatory ventilation (i) Indicative of worsening clinical status, severe hemodynamic dysfunction, and reduced functional capacity in CHF [121 –126 ] Three or more regular
oscillations (standard deviation of three consecutive cycle lengths within 20% of their average), with minimal average amplitude of ventilatory oscillation of 5 L/min [27 ] (ii) Responsive to interventions in CHF [101 ] Cardiovascular
Heart rate
O2 (beat/L)(i) Indicative of abnormal cardiovascular response to exercise [127 –130 ] <age—and gender-specific lower limits of normality [9 , 10 ] (ii) Adjunct for the diagnosis of myocardial ischemia [88 , 131 –133 ] Changes in linearity with increases in steepness [88 , 132 , 133 ] Heart rate recovery (HRR) (beats/min) (i) Prognosis in asymptomatic subjects referred for exercise testing [134 ], CHF [135 ], PAH [28 ], Type 2 diabetes [136 ], and COPD [137 ] Mortality in patients referred for exercise testing (ii) Disease severity in metabolic syndrome [138 ], obstructive sleep apnea [139 ], sarcoidosis [140 ], rheumatological diseases [141 , 142 ], polycystic ovary syndrome [143 ], polycystic kidney disease [144 ], and HIV infection [145 ] Treadmill, cooldown: 1 min ≤ 12 [134 , 150 , 151 ] (iii) Responsive to aerobic training in CHF, COPD, obstructive sleep apnea, and systemic lupus erythematosus [146 –149 ] Treadmill, no cooldown: 1 min ≤ 18 [135 ] 2 min ≤ 22 [152 ] Treadmill, no cooldown: 2 min ≤ 42 [153 ] Mortality in CHF Treadmill, cooldown: HRR1 min < 6.5 [154 ] Treadmill, no cooldown: 1 min ≤ 12 [155 ] Bike, cooldown: 1 min < 17 [156 ] Mortality in PAH 1 min ≤ 18 [28 ] Mortality in COPD 1 min ≤ 14 [137 ] Mortality in Type 2 diabetes Treadmill, cooldown: HRR1 min < 12 2 min < 28 [136 ]
