Table 1– Exercise training and oxygen

First author [ref.]	Active/ control n	Inclusion criteria	Oxygen treatment	Exercise training	Main outcome parameters	Results active/placebo
Rooyackers [23]	12/12	P_O₂ >8.5 kPa, nocturnal S_O₂ >90%, S_{O₂,max exercise} <90%, ΔP_{A–a,O₂,rest max exercise} >2 kPa	4 L·min⁻¹	Strength + endurance (cycling), S_O₂ >90%: 10 weeks, 5 days·week⁻¹, 80 min·day⁻¹	CWRT, 6MWD, CRQ	ns
Fichter [24]	5/5		35%	Cycling: 4 weeks, 5 days·week⁻¹	W_{max,cycle ergometry}	ns
Garrod [25]	11/11	FEV₁ <40%, S_{O₂,exercise} <90% and ΔS_O₂ >4%	4 L·min⁻¹	Cycling/walking: 6 weeks, 3 days·week⁻¹, 1 h·day⁻¹	ISWT, CRQ	ns
Wadell [26]	10/10	S_O₂,6MWD <92%, P_O₂ >7.8 kPa	5 L·min⁻¹	Walking, S_O₂ >90%: 8 weeks, 3 days·week⁻¹, 30 min·day⁻¹	6MWD	ns
Emtner [27]	14/15	FEV₁ <50%, P_O₂ >7.3 kPa, S_O₂,CWRT >88%	3 L·min⁻¹	Cycling: 7 weeks, 3 days·week⁻¹, 45 min·day⁻¹	CWRT	14.5/10.0 min*
Scorsone [28]^#	7/9		40%	Cycling; 8 weeks, 3 days·week⁻¹, 40 min·day⁻¹	W_{max,cycle ergometry}, CWRT	ns

P_O₂: partial pressure of oxygen; S_O₂: oxygen saturation; Δ: change; P_A–a,O₂: alveolar–arterial oxygen gradient; FEV₁: forced expiratory volume in 1 s; 6MWD: 6-min walk distance; CWRT: constant work rate test; CRQ: Chronic Respiratory Questionnaire; W_max: maximum work; ISWT: Incremental Shuttle Walk Test; ns: not significant. ^#: three-arm study: 40% O₂, heliox (He 60%/O₂ 40%) and air, presented results 40% O₂ versus air. *: p<0.05.