RESULTS
A total of 147 children and adolescents were recruited (healthy n = 48,
asthmatic n = 48, and CF = 51). Table 1 presents the baseline
characteristics of the study sample. Participants were homogeneous in
age (11.8 ± 3.0 years) and sex distribution. As expected, there were
significant differences between asthmatics and CF children when compared
to their healthy peers for anthropometric and lung function
measurements. Asthma and CF groups presented lower FEV1when compared to healthy controls, although there was no difference
between asthmatics and CF patients in lung function.
As for cardiorespiratory fitness, significant differences were found for
both VO2peak (F(2,144)=16.992,p <0.0001) and BR (F(2,144)=12.067,p <0.0001) (Figure 1). Asthmatics showed lower
VO2peak when compared to both healthy and CF subjects.
On the other hand, no differences in VO2peak between
healthy and CF patients were described. Although patients with CF had no
decrease in VO2peak, a lower BR was found when compared
to both healthy and asthmatic groups. Comparison between asthmatic and
healthy children revealed no differences in the BR (Figure 1).
The main cardiopulmonary exercise testing variables at
VT1 and peak exercise are presented in Table 2.
Significant differences between groups were observed for both
VE/VO2 (F(2,143)=15.384,p <0.0001) and VE/VCO2(F(2,143)=15.194, p <0.0001) at
VT1 (Figure 2A and 2B). For the
VE/VO2 at VT1, patients
with CF reported the highest values when compared to both asthma and
healthy individuals. In addition, asthmatic patients also presented
higher VE/VO2 at VT1when compared to healthy subjects (Figure 2A). As for
VE/VCO2 at VT1 both
asthmatic and CF patients showed higher values when compared to healthy
participants, while no differences between asthma and CF groups were
revealed (Figure 2B). There were also differences for both
VE/VO2 (F(2,139)=7.895,p =0.001) and VE/VCO2(F(2,144)=6.802, p =0.002) at peak exercise,
indicating that CF patients presented higher values for both variables
when compared to healthy individuals (Figures 2C and 2D).