Reference values for cardiopulmonary exercise testing in healthy subjects – an updated systematic review

Figures & data

Figure 1. The PRISMA flow diagram displaying the selection of studies and reasons for exclusion.

Table 1. Overall study characteristics.

Reference	Sample size (males/females)	Age (years)	Sample characteristics	Country	Smokers included	Treadmill or cycle ergometry	Protocol	Primary parameters measured	Methodology	Time averaging (s)
Aadland 2016	765 (402/363)	20–85	Population-based, retrospective	Norwegian	Yes	TM	Modified Balke protocol	VO2, HR, RER	Gas analyzer	30 s
Abella 2016	215 (138/77)	6–17	Hospital-based, retrospective	Argentina	?	TM	Bruce protocol	VO2^a, HR, RER, O2-pulse, VE/VCO2-slope, SpO2	B × B	10–60 s
Agostini 2017	500 (260/240)	18–77	Population-based, prospective	Italy	Yes	CY	Personalized incremental ramp protocol	VO2, CO, arteriovenous oxygen difference, HR, SV, CI	B × B	20 s
Almeida 2014	3119 (1624/1495)	8–90	Hospital-based, retrospective	Brazil	Yes	TM	Personalized incremental ramp protocol	HR, SBP, DBP, RER, VE, VO2	B × B	20 s
Blanchard 2018	228 (112/116)	12–17	Population-based, prospective	Canada	No	CY	Personalized incremental ramp protocol	VO2, O2-pulse, WR^a, VE, HR, RER, OUES, OUES-slope below VAT, VE/VCO2-slope, VE/VCO2-slope below VAT, VE/VCO2 at VAT, VO2/WR-slope, O2-pulse/WR-slope, HRR^c	B × B	?
Bongers 2015	214 (114/100)	8–19	Population-based, prospective	The Netherlands	?	CY	Godfrey protocol (10, 15, or 20 W/min)	WR, HR, RER, VO2^a, VE, VE/VCO2-slope, OUES, OUEP, OUE at VAT	B × B	30 s
Buys 2014	1411 (877/534)	20–60	Population-based, prospective	Belgium	?	CY	Incremental protocol (20 W/min)	VO2, WR, HR, RER, OUES	B × B	30 s
Dilber 2015	164 (99/65)	11–17	Hospital-based	Croatia	?	TM	Bruce protocol	WR^1, HR^a,b, RER, VO2^a, O2-pulse^a,b, ΔVO2/ΔWR, SBP^a,b, BF^a,b, VT^a,b, VE^a, VE/VO2^a, VE/VCO2^a, VD/VT^a, PETCO2^a	B × B	15 s
Duff 2017	70 (33/37)	10–18	Population-based, prospective	Canada	?	TM	Incremental TM protocol (start at 2.0 mph, 1%, increase of 0.5 mile/hr/min)	VO2, VE, HR, RER	B × B	15 s
Genberg 2016	181 (90/91)	50	Population-based, prospective	Sweden	Yes	CY	Incremental protocol (10 W/min, with initial work rate of 30 W (women) and 50 W (men)	WR, VO2^a, VE/VCO2 at VAT	B × B	?
Herdy 2015	3922 (2388/1534)	15–74	Hospital-based, prospective	Brazil	No	TM	Personalized incremental ramp protocol	VO2	Mixing chamber gas analyzer	10 s
Hossri 2018	217 (69/148)	4–21	Hospital-based, retrospective	Brazil	?	TM	Personalized incremental ramp protocol	OUES, PETCO2 at rest, VE/VCO2-slope, VAT, O2-pulse, RER, SpO2^2	Gas analyzer	30 s
Kaafarani 2017	184 (113/71)	6–18	Hospital-based, retrospective	The Netherlands	No	CY	Godfrey protocol (10, 15, or 20 W/min)	VO2, WR, RER, SBP	B × B	30 s
Kaminsky 2015^d	7783 (4611/3172)	20–79	Population-based, retrospective	United States	?	TM	Personalized incremental ramp protocol	VO2, HR, RER	Gas analyzer	20–30 s
Kaminsky 2017^d	4494 (1717/2777)	20–79	Population-based, retrospective	United States	?	CY	Personalized incremental ramp protocol	WR, HR, RER	Gas analyzer	20–30 s
Kaminsky 2018^d	5232 (3043/2189)	20–79	Population-based, retrospective	United States	?	TM	Personalized incremental ramp protocol	VE, VO2, HR^2, SBP at rest, DBP at rest	Gas analyzer	20–30 s
Kokkinos 2018^d	5100 (3378/1722)	20–79	Random, population-based, retrospective	United States	Yes	CY	?	VO2	Open circuit spirometry	30–60 s
Lintu 2014	140 (71/69)	9–11	Hospital-based, retrospective	Finland	?	CY	Incremental (1 W/6 s, with initial work rate of 20 W)	WR, VO2, VE, RER, VE/VCO2 (lowest), O2-pulse, HR^b,c, SBP^b,c	B × B	15 s
Loe 2014	3512 (1758/1754)	20–90	Random, population-based, prospective	Norway	Yes	TM	Incremental (0.5–1.0 km/h/min or 1–2% incline)	WR^a, HR^a, VO2^a, VE^a, BF^a, VT^a, VCO2^a, RER^a	B × B	?
Meyers 2017^d	7759 (4601/3158)	20–79	Population-based, retrospective	United States	?	TM	Personalized incremental ramp protocol	VO2, HR, RER, SBP, DBP	?	20–30 s
Mylius 2019	4477 (3570/907)	7–65	Population-based, retrospective	The Netherlands	No	CY	Personalized incremental ramp protocol	VO2	B × B	30–60 s
Neto 2019	18189 (12555/5634)	13–69	Population-based, retrospective	Brazil	?	TM	Personalized incremental protocol	VO2	B × B	30 s
Ozemek 2017	2644 (1510/1134)	18–76	Population-based, retrospective	United States	No	TM	Bruce, modified Bruce, BSU Bruce ramp, Balke, modified Balke, and personalized incremental protocol	VO2, HR^b	Open circuit spirometry	?
Pistea 2016	99 (58/41)	>70	Population-based, prospective	France	Yes	CY	Incremental 10, 15, 20, 25, or 30 W/min (depending on subjects age, body mass, and physical fitness level)	VO2, HR^b, WR, VE^b, VE/VCO2, VE/VO2, RER	B × B	20 s
Rapp 2018	10090 (6462/3628)	21–83	Population-based, retrospective	Germany	Yes	CY	Ramp protocol + multistage protocols	VO2, SBP, DBP	B × B	10 s
Sabbahi 2018^d	2736 (1525/1211)	20–79	Random, population-based, retrospective	United States	?	TM	?	SBP^b, DBP^b, HR	NA	NA
Stensvold 2017	310 (150/160)	70–77	Random, population-based, prospective	Norway	Yes	CY/TM	10 W/30 s, on CY, or incremental protocol on TM	HR^c, VO2^a, RER^a, VCO2^a, BF^a, VE^a, BR, VT, O2-pulse, VE/VO2^a, VE/VCO2^a, SBP, DBP	B × B	Average of three highest consecutive values
Tompouri 2017	38 (18/20)	9–11	Hospital-based, prospective	Finland	?	CY	Incremental 1 W/6 s, with initial work rate of 20 W	WR^a, VO2^a,b, RER	B × B	15 s
van de Poppe 2018	3463 (2868/595)	20–60	Population-based, retrospective	The Netherlands, Belgium	No	CY	Personalized incremental ramp protocol	WR, VO2, HR, RER	B × B	30 s

If not explicitly stated, a variable was obtained at peak exercise.

B × B = breath-by-breath; BF = breathing frequency; BR = breathing reserve; CI = cardiac index; CO = cardiac output; CY = cycle ergometry; DBP = diastolic blood pressure; HR = heart rate; HRR = heart rate reserve; NA = not applicable; O₂-pulse = oxygen-pulse; O₂-pulse/WR-slope = relation between oxygen-pulse and work rate; OUE = oxygen uptake efficiency; OUEP = oxygen uptake efficiency plateau; OUES = oxygen uptake efficiency slope; PETCO₂ = end tidal carbon dioxide pressure; RER = respiratory exchange ratio; s = seconds; SBP = systolic blood pressure; SpO₂ = peripherally measured oxygen saturation; SV = stroke volume; TM = treadmill ergometry; VAT = oxygen uptake at the ventilatory anaerobic threshold; VCO₂ = carbon-dioxide production; VD/VT = physiologic dead space to tidal volume ratio; VE = minute ventilation; VE/VCO₂ = minute ventilation to carbon dioxide production ratio; VE/VCO₂-slope = relationship between minute ventilation to carbon dioxide production; VE/VO₂ = minute ventilation to oxygen uptake ratio; VO₂ = oxygen uptake; VO₂/WR-slope = relation between oxygen uptake and work rate; ΔVO₂/ΔWR = delta oxygen uptake to delta work rate ratio (oxygen cost of work); VT = tidal volume; WR = work rate; ? = unknown.

^a: Variable(s) also obtained at the VAT; ^b: Variable(s) also obtained at rest; ^c: Variable(s) also obtained during recovery; ^d: data from the FRIEND registry.

Table 2. Methodological quality of the included studies list based on the ATS/ACCP guidelineappendi.

Reference	A/P	1	2	3	4	5	6	7	8	9	10	11	12	13	14	Total score
Aadland 2016	A	0	1	0	0	1	0	0	0	1	1	1	1	1	1	9
Abella 2016	P	0	0	0	0	1	0	0	0	0	1	1	0	0	0	3
Agostini 2017	A	1	0	0	0	1	0	0	1	0	1	1	1	0	1	7
Almeida 2014	A + P	0	1	0	0	1	1	0	0	0	1	1	0	1	0	6
Blanchard 2018	P	1	1	0	1	1	0	0	1	0	1	1	1	0	1	9
Bongers 2016	P	1	0	0	0	1	0	0	1	1	1	1	1	0	1	8
Buys 2014	A	1	0	1	0	1	1	0	1	1	1	1	1	1	1	11
Dilber 2015	P	0	0	0	0	1	0	0	?	0	1	1	0	0	0	3
Duff 2017	P	1	0	0	0	0	1	0	1	1	1	1	0	0	0	6
Genberg 2016	A	1	1	0	0	1	1	1	1	1	1	1	0	0	0	9
Herdy 2016	A + P	1	1	0	1	1	1	0	1	0	1	1	0	1	1	10
Hossri 2018	A + P	0	0	0	0	1	1	0	0	0	0	1	1	0	1	5
Kaafarani 2017	P	1	0	0	1	1	0	0	0	1	1	1	1	0	1	8
Kaminsky 2015	A	1	0	0	0	1	1	1	0	1	0	1	1	0	1	8
Kaminsky 2017	A	1	0	0	0	1	1	1	0	1	0	1	1	0	1	8
Kaminsky 2018	A	1	0	0	0	1	1	1	0	1	0	1	1	1	1	9
Kokkinos 2018	A	1	0	0	0	1	1	1	0	1	1	0	1	1	1	9
Lintu 2015	P	0	0	0	1	1	1	0	0	0	1	1	0	0	1	6
Loe 2014	A	1	0	0	0	1	1	1	1	1	1	1	0	0	1	9
Myers 2017	A	1	0	0	0	1	1	0	0	1	1	1	1	1	1	9
Mylius 2019	A + P	1	0	0	1	1	1	0	0	1	1	1	1	1	1	10
Neto 2019	A + P	1	0	0	0	1	1	0	0	1	1	1	1	0	1	8
Ozemek 2017	A	1	0	0	0	1	1	0	0	0	1	1	0	0	1	6
Pistea 2016	A	0	1	0	0	1	0	0	1	0	1	1	0	0	0	5
Rapp 2018	A	1	0	0	1	1	1	0	0	1	1	1	1	0	1	9
Sabbahi 2017	A	1	0	0	0	1	1	0	0	1	1	1	1	0	0	7
Stensvold 2017	A	1	1	0	0	1	1	0	1	1	1	1	1	0	1	10
Tompuri 2017	P	1	1	0	1	1	0	0	1	0	1	1	0	0	1	8
van de Poppe 2018	A	1	0	0	1	1	1	0	0	1	1	1	1	1	1	10

See appendix B for the methodological quality list based on the ATS/ACCP guideline.

A=adult subjects; P=pediatric subjects, 0= criterion is not met, 1= criterion is not met.

Table 3. Reference values of the included studies for cardiovascular parameters, ventilatory parameters, and ventilatory efficiency parameters.

Variable	Reference	Age-range	Sex	Prediction equation or reference data	R^2, SEE
Cardiovascular parameters
VO2max/VO2peak (mL/kg/min)	Aadland 2016	<55	M	VO2max/VO2peak = 22.04 + (−0.18 × age (years)) + (−0.13 × body mass (kg)) + (2.61 × time to exhaustion (min))	?,4.46
VO2max/VO2peak (mL/kg/min)	Aadland 2016	>55	M	VO2max/VO2peak = 40.05 + (−0.27 × age (years)) + (−0.13 × body mass (kg)) + (1.49 × time to exhaustion (min))	?,3.91
VO2max/VO2peak (mL/kg/min)	Aadland 2016	<55	F	VO2max/VO2peak = 23.03 + (−0.15 × age (years)) + (0.10 × body mass (kg)) + (1.95 × time to exhaustion (min))	?,3.87
VO2max/VO2peak (mL/kg/min)	Aadland 2016	>55	F	VO2max/VO2peak = 39.67 + (−0.25 × age (years)) + (0.13 × body mass (kg)) + (1.07 × time to exhaustion (min))	?,3.19
VO2max/VO2peak (mL/kg/min)	Almeida 2014	8–90	M/F	VO2max/VO2peak = 53.478 + (−7.518 × sex) + (−0.254 × age) + (0.430 × BMI) + (6.132 × physical activity)	0.679,?
VO2max/VO2peak (mL/kg/min)	Kokkinos 2018	20–79	M/F	VO2max/VO2peak = 1.74 × (WRpeak × 6.12/body mass (kg)) + 3.5
VO2max/VO2peak (mL/kg/min)	Kokkinos 2018	20–79	M	VO2max/VO2peak = 1.76 × (WRpeak × 6.12/body mass (kg)) + 3.5
VO2max/VO2peak (mL/kg/min)	Kokkinos 2018	20–79	F	VO2max/VO2peak = 1.65 × (WRpeak × 6.12/body mass (kg)) + 3.5
VO2max/VO2peak (mL/kg/min)	Myers 2017	20–79	M/F	VO2max/VO2peak = 79.9 – (0.39 × age) – (13.7 × sex (0 = male; 1 = female) – (0.127 × body mass (lbs))	0.62, 7.2
VO2max/VO2peak (mL/min)	Blanchard 2018	12–17	M	VO2max/VO2peak = (−0.297 × body height^2) + (105.9 × body height) + (36.6 × corrected body mass) + (0 × age) + −8660
VO2max/VO2peak (mL/min)	Blanchard 2018	12–17	F	VO2max/VO2peak = (−0.24 × body height^2) + (86.8 × body height) + (14.7 × corrected body mass) + (0 × age) + −6424
VO2max/VO2peak (mL/min)	Blanchard 2018	12–17	M	Z-score = VO2peak – [(−0.3 × body height^2) + (105.88 × body height) + (36.59 × body mass) + (−8660.14)]/(6.35 × body height) + (−717.05)
VO2max/VO2peak (mL/min)	Blanchard 2018	12–17	F	Z-score = VO2peak – [(−0.24 × body height^2) + (86.856 × body height) + (14.7 × body mass) + (−6424.42)]/(2.12 × body height) + (−45.9)
VO2max/VO2peak (mL/min)	Mylius 2019	7.9–65	M	VO2max/VO2peak = −2537.29 + 743.35 + (24.3 × body height) + (12.57 × body mass) + (spline function for age: estimate degrees of freedom: 4.263, reference degrees of freedom 5.260)	0.57, 556.5
VO2max/VO2peak (mL/min)	Mylius 2019	7.9–65	F	VO2max/VO2peak = −2537.29 + (24.3 × body height) + (12.57 × body mass) + (spline function for age: estimate degrees of freedom: 7.391, reference degrees of freedom 8.288)	0.57, 556.5
VAT (mL/min)	Blanchard 2018	12–17	M	VAT = (−0.146 × body height^2) + (56.3 × body height) + (18.0 × corrected body mass) + (−48.3 × age) + −3898
VAT (mL/min)	Blanchard 2018	12–17	F	VAT = (−0.00407 × body height^2) + (−2.14 × body height) + (15.9 × corrected body mass) + (−26.7 × age) + 1282
VAT (mL/min)	Blanchard 2018	12–17	M	Z-score = VAT – [(−0.13 × body height^2) + (52.37 × body height) + (17.21 × body mass) + (−51.9 × age) + (−3565.48)]/(3.24 × body height) + (−109.49)
VAT (mL/min)	Blanchard 2018	12–17	F	Z-score = VAT – [(−0.004 × body height^2) + (−2.14 × body height) + (15.91 × body mass) + (−26.72 × age) + (1281.8)]/(0.45 × body height) + (215.33)
HRpeak (beats/min)	Ozemek 2017	18–76	M	HRpeak = (−0.005 × age^2) – (0.33 × age) + 205 (cross-sectional)	0.386
HRpeak (beats/min)	Ozemek 2017	18–76	F	HRpeak = (0.0002 × age^3) – (0.02 × age^2) + (0.44 × age) + 191 (cross-sectional)	0.358
HRpeak (beats/min)	Ozemek 2017	18–76	M/F	HRpeak = (0.0002 × age^3) – (0.02 × age^2) + (0.44 × age) + 211 (cross-sectional)	0.369
HRpeak (beats/min)	Ozemek 2017	18–76	M	HRpeak = −0.83 × age + 215 (longitudinal)	BIC provided
HRpeak (beats/min)	Ozemek 2017	18–76	F	HRpeak = −0.74 × age + 211 (longitudinal)	BIC provided
HRpeak (beats/min)	Ozemek 2017	18–76	M/F	HRpeak = (0.0002 × age^2) – (0.03 × age^2) + 0.84 + 185 (longitudinal)	BIC provided
HRpeak (beats/min)	Blanchard 2018	12–17	M	HRpeak = (−0.000532 × body height^2) + (0.313 × body height) + (−0.259 × corrected body mass) + (0 × age) + 169.5
HRpeak (beats/min)	Blanchard 2018	12–17	F	HRpeak = (−0.0213 × body height^2) + (7.198 × body height) + (−0.193 × corrected body mass) + (−0.809 × age) + −391.1
HRpeak (beats/min)	Blanchard 2018	12–17	M	Z-score = HRpeak – [(−0.0005 × body height^2) + (0.31 × body height) + (−0.26 × body mass) + (169.45)]/(0.1 × body height) + (−7.47)
HRpeak (beats/min)	Blanchard 2018	12–17	F	Z-score = HRpeak – [(−0.02 × body height^2) + (7.2 × body height) + (−0.19 × body mass) + (−0.81 × age) + (−391.11)]/(−0.12 × body height) + (28.41)
O2-pulsepeak (mL/beat)	Blanchard 2018	12–17	M	O2-pulsepeak = (−0.00131 × body height^2) + (0.459 × body height) + (0.214 × corrected body mass) + (0 × age) + −37.48
O2-pulsepeak (mL/beat)	Blanchard 2018	12–17	F	O2-pulsepeak = (−0.00019 × body height^2) + (0.075 × body height) + (0.1007 × corrected body mass) + (0 × age) + −1.83
O2-pulsepeak (mL/beat)	Blanchard 2018	12–17	M	Z-score = O2-pulsepeak – [(−0.001 × body height^2) + (0.41 × body height) + (0.2 × body mass) + (−0.2 × age) + (−35.14)]/(0.03 × body height) + (−2.69)
O2-pulsepeak (mL/beat)	Blanchard 2018	12–17	F	Z-score = O2-pulsepeak – [(−0.0002 × body height^2) + (0.07 × body height) + (0.1 × body mass) + (−1.83)]/(−0.003 × body height) + (2.17)
Blood pressure (mm Hg)	Kaafarani 2017	6.2–18.6	M/F	Normality SBP = 0.00004 × (WRpeak^2) – 0.00526 × (WRpeak) + 0.46541 Mean SBP = 0.2853 × (WRpeak) + 111.46
WRpeak (W)	Blanchard 2018	12–17	M	WRpeak = (−0.0182 × body height^2) + (−5.324 × body height) + (2.824 × corrected body mass) + (4.170 × age) + 378.9
WRpeak (W)	Blanchard 2018	12–17	F	WRpeak = (−0.06025 × body height^2) + (20.57 × body height) + (0.741 × corrected body mass) + (0 × age) + −1622
WRpeak (W)	Blanchard 2018	12–17	M	Z-score = WRpeak – [(−0.02 × body height^2) + (−5.32 × body height) + (2.82 × body mass) + (−4.17 × age) + (378.86)]/(0.22 × body height) + (−7.62)
WRpeak (W)	Blanchard 2018	12–17	F	Z-score = WRpeak – [(−0.06 × body height^2) + (20.57 × body height) + (0.74 × body mass) + (−1622.29)]/(−0.28 × body height) + (−24.41)
WRpeak (W)	Poppe 2018	20–60	M/F	WRpeak = −102 + (1.5 × body mass (kg)) + (1.9 × body height (cm)) – (2.0 × age) – (sex × 60 (M:1; F:0))	0.57, 44.2
WRpeak (W)	Poppe 2018	20–60	M	WRpeak = (−0.967 × age^2) + (5.2057 × age) + 257.12	0.99
WRpeak (W)	Poppe 2018	20–60	M	WRpeak = (−0.0372 × body mass^2) + (8.0074 × body mass) – 92.929	0.99
WRpeak (W)	Poppe 2018	20–60	M	WRpeak = (0.0162 × body height) – (2.4774 × body height) + 227	0.99
WRpeak (W)	Poppe 2018	20–60	F	WRpeak = (−0.0012 × age^3) + (0.1147 × age^2) ^– (4.7471 × age) + 278.7	0.99
WRpeak (W)	Poppe 2018	20–60	F	WRpeak = (0.002 × body mass^3) ^– (0.4715 × body mass^2) + (38.12 × body mass) – 818.6	0.99
WRpeak (W)	Poppe 2018	20–60	F	WRpeak = (−0.0642 × body height^2) + (24.481 × body height) – 2101.7	0.99
WRpeak (W/kg)	Poppe 2018	20–60	M/F	WRpeak = 2.45 – (0.026 × body mass (kg)) + (0.024 × body height (cm)) – (0.024 × age) – (sex × 0.84 (M: 1; F: 0])	0.4,0.54
WRpeak (W/kg)	Poppe 2018	20–60	M	WRpeak = (−0.0008 × age^2) + (0.0247 × age) + 3.9059	0.99
WRpeak (W/kg)	Poppe 2018	20–60	M	WRpeak = (7E-06 × body mass^3) + (0.0016 × body mass^2) + (0.109 × body mass) + 2.022	0.99
WRpeak (W/kg)	Poppe 2018	20–60	M	WRpeak = (−4E-07 × body height^4) + (0.0003 × body height^3) – (0.083 × body height^2) + (9.8777 × body height) – 435.9	0.99
WRpeak (W/kg)	Poppe 2018	20–60	F	WRpeak = (−0.0005 × age^2) + (0.0139 × age) + 3.2404	0.99
WRpeak (W/kg)	Poppe 2018	20–60	F	WRpeak = (−0.0004 × body mass^2) + (0.029 × body mass) + 2.8378	0.99
WRpeak (W/kg)	Poppe 2018	20–60	F	WRpeak = (−0.0009 × body height^2) + 0.31 × body height) – 24.466	0.99
Ventilatory parameters
VEpeak (L/min)	Almeida 2014	8–90	M/F	VEpeak = 75.32 ± 15.78 (range 33.10–121.9) Tabulated data (n = 2495)	SD provided
VEpeak (L/min)	Blanchard 2018	12–17	M	Z-score = VEpeak − [(−0.002 × body height^2) + (−0.42 × body height) + (0.98 × body mass) + (3.17 × age) + (2.7)]/[(0.4 × body height) + (−52.54)]
VEpeak (L/min)	Blanchard 2018	12–17	F	Z-score = VEpeak − [(−0.007 × body height^2) + (2.56 × body height) + (0.53 × body mass) + (1.13 × age) + (−202.86)]/[(0.07 × body height) + (3.72)]
VEpeak (L/min)	Bongers 2016	8–18	M	VEpeak = 80 ± 25 (range 42–157) Tabulated data (n = 114)	SD provided
VEpeak (L/min)	Bongers 2016	8–18	F	VEpeak = 71 ± 21 (34–152) Tabulated data (n = 100)	SD provided
VEpeak (L/kg/min)	Bongers 2016	8–18	M	VEpeak = 1.7 ± 0.3 (0.9–2.5) Tabulated data (n = 114)	SD provided
VEpeak (L/kg/min)	Bongers 2016	8–18	F	VEpeak = 1.5 ± 0.3 (0.8–2.1) Tabulated data (n = 100)	SD provided
VEpeak (L/min)	Dilber 2015	11–17	M	VEpeak = 89.09 ± 30.1 Tabulated data (n = 99)	SD provided
VEpeak (L/min)	Dilber 2015	11–17	F	VEpeak = 67.29 ± 19.6 Tabulated data (n = 65)	SD provided
VEpeak (L/min)	Duff 2017	10–18	M/F	VEpeak = 99.2 (75.6–120.0) (median + IQR) Tabulated data (n = 70)
VEpeak (L/min)	Kaminsky 2018	20–79	M/F	VEpeak = 17.32 – (28.33 × sex (M = 0; F = 1)) – (0.79 × age (years)) – (1.85 × body height (inches))	21.7
VEpeak (L/min)	Lintu 2015	9–11	M	VEpeak = 69.0 ± 20.0 Tabulated data (n = 71)	SD provided
VEpeak (L/min)	Lintu 2015	9–11	F	VEpeak = 63.0 ± 18.0 Tabulated data (n = 69)	SD provided
VEpeak (L/min)	Loe 2014	20–90	M	VEpeak = 123.7 ± 25.7 Tabulated data per age group	SD provided
VEpeak (L/min)	Loe 2014	20–90	F	VEpeak = 81.8 ± 17.6 Tabulated data per age group	SD provided
VEpeak (L/min)	Pistea 2016	>70	M	VEpeak = 72.77 ± 18.31 Tabulated data (n = 58)	SD provided
VEpeak (L/min)	Pistea 2016	>70	F	VEpeak = 49.50 ± 13.22 Tabulated data (n = 41)	SD provided
VEpeak (L/min)	Stensvold 2017	70–77	M	VEpeak = 96.2 ± 21.7 Tabulated data (n = 768)	SD provided
VEpeak (L/min)	Stensvold 2017	70–77	F	VEpeak = 61.1 ± 21.6 Tabulated data (n = 769)	SD provided
VTpeak (L)	Blanchard 2018	12–17	M	Z-score = VTpeak − [(0.00002 × body height^2) + (0.002 × body height) + (0.02 × body mass) + (0.09 × age) + (−1.22)]/[(0.004 × body height) + (−0.46)]
VTpeak (L)	Blanchard 2018	12–17	F	Z-score = VTpeak − [(0.00005 × body height^2) + (−0.009 × body height) + (0.01 × body mass) + (0.06 × age) + (0.35)]/[(0.0008 × body height) + (0.17)]
VTpeak (L)	Dilber 2015	11–17	M	VTpeak = 2.22 ± 0.6 Tabulated data (n = 99)	SD provided
VTpeak (L)	Dilber 2015	11–17	F	VTpeak = 1.84 ± 0.8 Tabulated data (n = 65)	SD provided
VTpeak (L)	Loe 2014	20–90	M	VTpeak = 2.83 ± 0.67 Tabulated data per age group	SD provided
VTpeak (L)	Loe 2014	20–90	F	VTpeak = 1.90 ± 0.43 Tabulated data per age group	SD provided
VTpeak (L)	Stensvold 2017	70–77	M	VTpeak = 2.3 ± 0.5 Tabulated data (n = 768)	SD provided
VTpeak (L)	Stensvold 2017	70–77	F	VTpeak = 1.6 ± 0.3 Tabulated data (n = 769)	SD provided
BFpeak (breaths/min)	Dilber 2015	11–17	M	BFpeak = 49.64 ± 11.7 Tabulated data (n = 99)	SD provided
BFpeak (breaths/min)	Dilber 2015	11–17	F	BFpeak = 49.49 ± 9.1 Tabulated data (n = 65)	SD provided
BFpeak (breaths/min)	Stensvold 2017	70–77	M	BFpeak = 41.8 ± 8.0 Tabulated data (n = 768)	SD provided
BFpeak (breaths/min)	Stensvold 2017	70–77	F	BFpeak = 39.7 ± 7.1 Tabulated data (n = 769)	SD provided
Ventilatory efficiency parameters
OUEP	Bongers 2016	8–18	M	OUEP = 26.34 – (0.029 × age^2) + (1.641 × age)	0.9998
OUEP	Bongers 2016	8–18	F	OUEP = 28.437 – (0.00363 × age^2) + (1.1409 × age)	0.9999
OUES	Barron 2015	25–84	M	OUES = 0.7 – (11.51 × age) + (5.67 × body height) + (8.62 × body mass) – (49.99 × beta blocker) – (214.53 × current smoker) + (172.97 × FEV1)	P5 and P95 provided
OUES	Barron 2015	25–80	F	OUES = −182.4 – (8.89 × age) + (10.12 × body height) + (10.51 × body mass) – (117.65 × beta blocker) – (21.45 × current smoker) + (40.31 × FEV1)	P5 and P95 provided
OUES	Buys 2014	20–60	M	OUES = 3930 – (12.5 × age) OUES = 1093 – (18.5 × age) + (1479 × BSA)
OUES	Buys 2014	20–60	F	OUES = 3013 – (15 × age) OUES = 842 – (18.5 × age) + (1280 × BSA)
OUES	Bongers 2016	8–18	M	OUES = 577.2 + 6.2 × age^2 + 52 × Age	0.997
OUES	Bongers 2016	8–18	F	OUES = 342.4–2.589 × Age^2 × 214.6 × age	0.9993
OUES (10–100)	Blanchard 2018	12–17	M	Z-score = OUES10–100 − [(−0.24 × body height^2) + (81.44 × body height) + (38.25 × body mass) + (−6176.58)]/[(9.29 × body height) + (−1137.43)]
OUES (10–100)	Blanchard 2018	12–17	F	Z-score = OUES10-100 − [(−0.37 × body height^2) + (130.32 × body height) + (15.27 × body mass) + (−19.1 × age) + (−9 721.78)]/[(4.91 × body height) + (−474.83)]
OUES/BSA	Hossri 2018	4–21	M/F	OUES/BSA LLN: 1200
OUES/kg	Hossri 2018	4–21	M/F	OUES/kg ULN: 34.63
OUES/kg	Bongers 2016	8–18	M	OUES/kg = 21.757 – (0.0011 × age^4) + (0.0562 × age^3) – (1.0675 × age^2) + (8.8991 × age)	0.9063
OUES/kg	Bongers 2016	8–18	F	OUES/kg = 41.3 + (0.0006 × age^4) + (0.0045 × age^3) + (0.3241 × age^2) + (1.4446 × age)	0.991
VE/VCO2 at the VAT	Loe 2014	20–90	M	VE/VCO2 = 26.7 ± 2.4 Tabulated data per age group	SD provided
VE/VCO2 at the VAT	Loe 2014	20–90	F	VE/VCO2 = 28.5 ± 3.6 Tabulated data per age group	SD provided
VE/VCO2 at the VAT	Genberg 2016	50	M	VE/VCO2 = 27.5 ± 2.70	SD provided
VE/VCO2 at the VAT	Genberg 2016	50	F	VE/VCO2 = 27.9 ± 3.24	SD provided
VE/VCO2 minimum	Lintu 2015	9–11	M	VE/VCO2 normal range: 24–32.9	SD provided
VE/VCO2 minimum	Lintu 2015	9–11	F	VE/VCO2 normal range: 25–33.8
VE/VCO2 peak	Pistea 2016	>70	F	VE/VCO2 = 34.83 ± 5.66	SD provided
VE/VCO2 peak	Pistea 2016	>70	M	VE/VCO2 = 34.19 ± 4.63	SD provided
VE/VCO2 peak	Loe 2014	20–90	M	VE/VCO2 = 29 ± 3.3 Tabulated data per age group	SD provided
VE/VCO2 peak	Loe 2014	20–90	F	VE/VCO2 = 29.3 ± 4 Tabulated data per age group	SD provided
VE/VCO2 peak	Stensvold 2017	70–77	M	VE/VCO2 = 32.6 ± 4.4 (26.6–28.7)	P5 and P95 provided
VE/VCO2 peak	Stensvold 2017	70–77	F	VE/VCO2 = 31.8 ± 4.1 (26.3–38.3)	P5 and P95 provided
VE/VCO2-slope	Abella 2016	6–17	M/F	Data shown in graph only, no equation provided	R^2 = 0.336
VE/VCO2-slope (up to the VAT)	Dilber 2015	11–17	M	VE/VCO2-slope = 27 ± 2.9	SD provided
VE/VCO2-slope (up to the VAT)	Dilber 2015	11–17	F	VE/VCO2-slope = 28.16 ± 2.8	SD provided
VE/VCO2-slope (up to the VAT)	Blanchard 2018	12–17	M	Z-score = VE/VCO2-slope − [(−0.0004 × body height^2) + (0.24 × body height) + (−0.1 × body mass) + (−1.01 × age) + (15.1)]/[(−0.03 × body height) + (8.71)]
VE/VCO2-slope (up to the VAT)	Blanchard 2018	12–17	F	Z-score = VE/VCO2-slope − [(−0.002 × body height^2) + (0.63 × body height) + (0.06 × body mass) + (−0.31 × age) + (−24.88)]/[(−0.02 × body height) + (5.8)]

BF_peak = breathing frequency at peak exercise; BMI-body mass index; BSA = body surface area; F = women; HR_peak = heart rate at peak exercise; IQR = interquartile range; LLN = lower limit of normal; M = men; O₂-pulse_peak = oxygen-pulse at peak exercise; OUEP = oxygen uptake efficiency plateau; OUES = oxygen uptake efficiency slope; SBP = systolic blood pressure; SD = standard deviation; SEE = standard error of the estimate; ULN = upper limit of normal; VAT = oxygen uptake at the ventilatory anaerobic threshold; VE_peak = minute ventilation at peak exercise; VE/VCO₂ = minute ventilation to carbon dioxide production ratio; VE/VCO₂-slope = relation between minute ventilation and carbon dioxide production; VO_2max = maximal oxygen uptake; VO_2peak = oxygen uptake at peak exercise; VT_peak = tidal volume at peak exercise; WR_peak = work rate at peak exercise.