Background. Previous studies have shown female sex, impaired pulmonary function, older age, malnutrition, and colonization of the respiratory tract by Pseudomonas cepacia to be associated with a poor prognosis in patients with cystic fibrosis. We sought to determine the prognostic value of exercise testing in addition to the other prognostic factors. Methods. A total of 109 patients with cystic fibrosis, 7 to 35 years old, underwent pulmonary-function and exercise testing in the late 1970s. They were followed for eight years to determine the factors associated with subsequent mortality. Survival rates were calculated with standard life-table methods. Cox proportional-hazards regression models were used to determine crude relative risks of mortality and relative risks adjusted for age, sex, body-mass index, forced expiratory volume in one second (FEV1), end-tidal partial pressure of carbon dioxide (PCO2) at peak exercise, and oxygen consumption at peak exercise (Vo2peak). Results. Patients with t...

https://www.nejm.org/doi/pdf/10.1056/NEJM199212173272504

The Prognostic Value of Exercise Testing in Patients with Cystic Fibrosis

Pulmonary rehabilitation - 1999

A randomized controlled trial of a 3-year home exercise program in cystic fibrosis

The aim of this study was to compare aerobic and resistance training in children with cystic fibrosis (CF) admitted to hospital with an intercurrent pulmonary infection with a control group. The subjects were randomized into three groups on the first day of admission. The fat-free mass (FFM) was calculated, using the skin fold thickness from four sites (biceps, triceps, subscapular, and iliac crest). Pulmonary function tests were performed within 36 hr of admission and repeated on discharge from the hospital, and again at 1 month after discharge. All subjects performed an incremental treadmill exercise test, using a modified Bruce protocol. Lower limb strength was measured using a Cybex dynamometer. An assessment of quality of life was made using the Quality of Well Being Scale, as previously reported. Activity levels were measured using a 7-day activity diary, and subjects also wore an accelerometer on their hips. There were no significant differences between the three groups in terms of disease severity, and length of stay in hospital. Subjects in all three groups received intravenous antibiotics and nutritional supplementation as determined by the physician. Children randomized to the aerobic training group participated in aerobic activities for five sessions, each of 30-min duration, a week. The children randomized to the resistance training group exercised both upper and lower limbs against a graded resistance machine. Subjects in the control group received standard chest physiotherapy. Our study demonstrated that children who received aerobic training had significantly better peak aerobic capacity, activity levels, and quality of life than children who received the resistance training program. Children who received resistance training had better weight gain (total mass, as well as fat-free mass), lung function, and leg strength than children who received aerobic training. A combination of aerobic and resistance training may be the best training program, and future studies to assess optimal training programs for CF patients are indicated.

Randomized controlled study of in-hospital exercise training programs in children with cystic fibrosis

We studied the impact of a 6-wk supervised, multimodality endurance exercise training program (EXT) on strength and endurance of ventilatory and peripheral muscles in patients with chronic airflow limitation (CAL), and determined whether potential improvements contributed to relief of exertional breathlessness (B) and perceived leg effort/discomfort (LE), respectively. Twenty breathless patients with stable CAL (FEV1 = 41 +/- 3% predicted; mean +/- SEM) were tested at 6-wk intervals at baseline, after a nonintervention control period (pre-EXT), and post-EXT. Measurements included: pulmonary function tests (PFTs), maximal inspiratory/expiratory pressures (MIP, MEP), inspiratory muscle endurance (V(LIM)), quadriceps strength and endurance, exercise endurance, and submaximal cycle exercise with cardioventilatory and symptom responses. Measurements at baseline and pre-EXT were identical. Post-EXT, PFTs did not change; exercise endurance measured on the treadmill, cycle ergometer, arm ergometer, and by 6-min walk distance increased 40 +/- 8%, 43 +/- 10%, 12 +/- 5%, and 34 +/- 9%, respectively (p < 0.05); quadriceps strength increased 21 +/- 5% (p < 0.01); MIP and MEP increased 29 +/- 11% and 27 +/- 11%, respectively (p < 0.05); V(LIM) increased almost threefold (p < 0.05). At isotime near end-exercise, B, LE, carbon dioxide production (VCO2), oxygen consumption (VO2), ventilation, and breathing frequency (F) all fell after EXT (p < 0.05): deltaB correlated with deltaF (r = 0.58, p < 0.01). Increased MIP and V(LIM) did not correlate with improved breathlessness or exercise endurance. Similarly, changes in quadriceps strength and endurance did not correlate with changes in LE or exercise endurance. In conclusion, general nonspecific EXT improved ventilatory and peripheral muscle function in severe CAL, but such improvements did not appear to contribute significantly to reduced exertional symptoms and enhanced exercise performance.

Kathe J. Germann

Papers

Exercise conditioning and cardiopulmonary fitness in cystic fibrosis. The effects of a three-month supervised running program.

The obesity hypoventilation syndrome in children with the Prader-Willi syndrome: a possible role for familial decreased response to carbon dioxide.