Summary of exercise outcomes
| Author [Ref.] | Exercise tests | Findings relating to exercise (at symptom limitation) |
| Babb [28] | Three maximal symptom-limited incremental CPETs | Increased ventilation (Heliox21)*** |
| Eves [29] | One symptom-limited CPET and four constant rate CPETs (60% WRmax) | Increased ventilation (Heliox21)*, increased endurance time (Heliox28, Heliox21 and O2 28%)* |
| Johnson [30] | Three maximal symptom limited CPETs (treadmill) pre/post 6-week pulmonary rehab (exercise and education) | No training benefits Heliox21 and NIPPV |
| Laude [31] | Incremental shuttle walk tests | Increased walk distance*** (all gas mixes) |
| Marciniuk [32] | One maximal symptom limited CPET and 6MWT, and four 6MWTs on two visits | Increased walk distance*** (Heliox30) |
| Oelberg [33] | Two incremental CPETs | No change in peak work loads |
| Palange [34] | One maximal symptom limited CPET and two constant rate CPETs | Increased endurance*** (Heliox21), no significant improvements in lung mechanics |
| Richardson [35] | Three incremental maximal CPETs and single knee extensor ergometry testing | Increased peak work*, increased ventilation* (Heliox21) |
CPET: cardiopulmonary exercise testing; WRmax: maximal work rate; NIPPV: noninvasive positive pressure ventilation; 6MWT: 6-min walk test. *: p<0.05; ***: p<0.001.