| dc.description.abstract | This study sought to determine whether a 6-week physical rehabilitation programme has a measurable influence on heart rate responsiveness to changing metabolic demand in patients with pulmonary fibrosis. Fifteen individuals (13 with idiopathic pulmonary fibrosis and two with pulmonary fibrosis associated with rheumatoid disease) underwent assessments of physical function (6-min walk test), ventilatory function
(spirometry), and cardio-respiratory function (respiratory gas analysis
and electrocardiogram [ECG] recording during a protocol consisting of
periods of rest, incremental bicycle exercise to maximal effort, and
post-exercise recovery). RR (beat-to-beat cardiac intervals) data were
derived from the ECG and used to quantify (a) heart rate variability (HRV)
and (b) cardiac acceleration (AC) and deceleration capacities (DC) (via
phase rectified signal averaging). Following the rehabilitation programme, heart rate was elevated by 11%–18% during exercise and recovery states. HRV was not statistically influenced by rehabilitation
during any stage of the assessment protocol; however, qualitative
changes were apparent with HRV increasing by 68%–75% during all
stages of the protocol. Statistically, AC and DC were similar pre- and
postrehabilitation (AC= -2.7 and -3.2 msec; DC= 2.3 and 3.2 msec, respectively) but again we observed qualitative improvements in these indices of 19% and 38%, respectively. These results provide initial evidence that physical rehabilitation improves heart rate dynamics (viamodulation of autonomic control of heart rate) in idiopathic pulmonary
fibrosis patients, even when respiratory and physical functions are unchanged or diminished. | en_US |
