Capacidade de exercício e efeitos de diferentes intensidades de exercício resistido em um treinamento físico combinado em pacientes com doença pulmonar obstrutiva crônica
Abstract
The scientific literature of patients with Chronic Obstructive Pulmonary
Disease (COPD) brings several specific aspects in relation to exercise capacity and
physical training. However, there are gaps that have not been elucidated, bringing
scientific questions that enabled this thesis development. The questions presented were:
1) Do patients with more symptomatic COPD present different exercise capacity on a
cycle ergometer according to disease severity? 2) What limiting factors of exercise
capacity are related to greater functional impairment of patients with COPD and greater
disease severity? 3) In patients with COPD, which intensity of resistance training in a
combined physical training produces more positive effects on peripheral muscle
strength, exercise capacity, symptoms perception and quality of life? Thus, two studies
were performed involving the problematic presented with following aims: 1) to identify
how the limiting factors (ventilatory, cardiovascular, oxygenation and peripheral
muscles) are involved in exercise performance and to determine whether there is
difference on exercise capacity in more symptomatic patients with different disease
severity; 2) to compare the effect of two combined trainings, different regarding the
intensity of the resistance training, on peripheral muscle strength, exercise capacity,
symptoms and quality of life in patients with COPD and to verify which intensity of
training was capable of presenting a larger proportion of responder patients. Methods:
The first study was a cross-sectional study with thirty-eight symptomatic patients with
COPD (COPD assessment test ≥ 10 points) that were assessed by: Spirometry,
Symptom-limited Cardiopulmonary Exercise Testing (CPET), Six Minute Walk Test
(6MWT), isometric muscle strength test of knee extensors (KExt) and hip abductors
(HAbd) with Microfet2 dynamometer. Subjects were grouped according to airway
obstruction level [Group 1: FEV1 ≥ 50% (n=17, 66±9yrs, FEV1=61.1± 9.9%pred) and
Group 2: FEV1 < 50% (n=21, 67.8±8.9yrs, FEV1=36.3±8.5%pred)]. In second study,
with intervention program for patients with COPD, thirty-one patients were assessed
and reassessed by: CAT, Saint George’s Respiratory Questionnaire (SGRQ); isometric
muscle strength of KExt and elbow flexors (EFlex); 6MWT; Symptom-limited CPET;
constant load cardiopulmonary test (CL-CPET) and one repetition maximum test
(1RM). Patients were randomized in two groups and underwent 36 training sessions:
combined training with low-intensity resistance training, from 30%1RM to 45%1RM
for upper limbs and to 51%1RM for lower limbs (LIRT: n=16, 68.1±9.3years,
10
FEV1=50.0±15.7%pred), and combined training with high intensity resistance training,
from 60%1RM to 75%1RM for upper limbs and to 81%1RM for lower limbs (HIRT:
n=15, 70±6.5years, FEV 1 =46.8 ± 14.5%pred). Both groups performed aerobic training
with work load corresponding to 80% VO2peak in symptom-limited CPET. Results:
More symptomatic patients with more severity COPD had significantly lower 6MWD,
besides lower oxygen saturation and ventilatory reserve in peak CPET, being that the
prevalence of this condition in peak exercise occurred in higher proportion in this
group. Furthermore, there were significant differences in isometric strength between
groups, being KExt strength able to predict approximately 52% of CPET maximal load.
For patients that performed combined training with different intensities of resistance
training, there were significant differences regarding symptoms (CAT), quality of life
(SGRQ) and exercise capacity (6MWD and Tlim) in both groups, nevertheless, only
HIRT presented significative improvement in isometric muscle strength of KExt and
EFlex). Both trainings presented values above the minimum clinically important
difference (MCID) to symptom and exercise capacity. However, quality of life and
KExt and EFlex isometric muscle strength only presented improvements higher than
MCID in group HIRT, which also presented a significantly larger number of responder
patients considering isometric muscle strength. Conclusion: More symptomatic patients
with COPD with higher disease severity present more limitation in exercise tolerance,
being lower ventilatory reserve, oxygenation deficit and KExt muscle strength more
pronounced limiting factors in these patients. Additionally, aerobic training associated
to resistance training was effective to improve symptoms and exercise capacity
regardless the intensity of the strength training. However, high intensity resistance
training may lead to greater gains regarding quality of life and peripheral muscle
strength, which indicates that patients respond more and better to this intensity of
training, as well as present greater clinical relevance.