Interval exercise training in cystic fibrosis -- effects on exercise capacity in severely affected adults.

The aims of the present study were to investigate the effects of IT on lung function power (P) and oxygen uptake (VO2) at peak performance (peak) and ventilatory anaerobic threshold (VAT) in CF patients who were unable to participate in a standard exercise program (SEP) and to compare these IT responses with corresponding effects in CF patients performing SEP. 20 patients (FEV1 25.5 ± 7.5%; pred; SpO2 < 90% at rest or P lower than 0.3 W/kg) who were unable to participate in SEP were allocated to IT (5 × 20 min weekly). 23 patients (FEV1 31.6 ± 4.2%; p < 0.05) did 5 × 45 min per week of SEP. Lung function remained unchanged in both groups. VO2peak and PVAT increased in both groups (p < 0.05). However, only after the SEP an increase in Ppeak (p < 0.05) and only after IT a higher VO2VAT (p < 0.05) were found. Compared to SEP, IT improved submaximal exercise capacity to a greater extent whereas responsiveness on peak performance was higher in SEP. This seems to indicate a specific potential of IT for positive peripheral muscular adaptations in spite of diminishing potential of pulmonary improvement. IT represents an alternative, effective and safe training regimen with patients with CF and severe lung disease, with a greater potential than SEP.