Impaired aerobic function in patients with cystic fibrosis during ramp exercise
Research output: Contribution to journal › Article › peer-review
Methods: Ten patients with stable, mild-to-moderate CF (12.7 ± 2.8 yr) and 10 healthy controls (CON, 12.8 ± 2.8 yr) completed a combined ramp and supramaximal cycling test to determine maximal O2 uptake (V˙O2max). Changes in gas exchange and ventilation, HR, and m. vastus lateralis HHb (near-infrared spectroscopy) were assessed. Δ[HHb]-work rate and Δ[HHb]-V˙O2 profiles were normalized and fit using a sigmoid function.
Results: Aerobic function was impaired in CF, indicated by very likely reduced fat-free mass-normalized V˙O2max (mean difference, ±90% confidence interval: −7.9 mL·kg−1·min−1, ±6.1), very likely lower V˙O2 gain (−1.44 mL·min−1·W−1, ±1.12), and a likely slower V˙O2 mean response time (11 s, ±13). An unclear effect was found upon the absolute and relative work rate (−14 W, ±44, and −0.7% peak power output, ±12.0, respectively) and the absolute and percentage (−0.10 L·min−1, ±0.43, and 3.3% V˙O2max, ±6.0) V˙O2 corresponding to 50% Δ[HHb] amplitude, respectively, between groups. However, arterial oxygen saturation (SpO2) was very likely lower in CF (−1%, ±1) and demonstrated moderate-to–very large relations with parameters of aerobic function.
Conclusions: Young patients with mild-to-moderate CF present with impaired aerobic function during ramp incremental cycling exercise. Because the rate of fractional O2 extraction during ramp cycling exercise was not altered by CF, yet SpO2 was lower, the present findings support the notion of centrally mediated oxygen delivery to principally limit the aerobic function of pediatric patients with CF during ramp incremental cycling exercise.
|Journal||Medicine and Science in Sports & Exercise|
|Publication status||Published - 1 Dec 2014|
- Impaired aeurobic function
Rights statement: This is a non-final version of an article published in final form in Saynor ZL, Barker AR, Oades PJ, Williams CA. Impaired aerobic function in patients with cystic fibrosis during ramp exercise. Med Sci Sports Exerc. 2014 Dec;46(12) 2271-2278. doi:10.1249/mss.0000000000000369
Accepted author manuscript (Post-print), 1.33 MB, PDF document