Physical Training and Heart Rate Variability in COPD
Condition: Chronic Obstructive Pulmonary Disease (COPD)
MeSH terms: Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
Study type: Interventional

Summary: 
      To contrast the potential effects of physical exercise training program (PTP) of a 6 versus
      12 weeks on cardiac autonomic modulation by linear and non-linear heart rate variability
      (HRV) indices and functional capacity in moderate-to-severe COPD patients.
    

Detailed description: 
      This is a prospective randomized controled trial. A total of fifty two patients were
      recruited, however, only 32 patients met all inclusion criteria. Patients that were included
      presented: 1) a diagnosis of COPD according to criteria set forth by the Global Initiative
      for Chronic Obstructive Lung Disease (19), 2) compliance with medical management, 3) no
      change in medical management and no decompensation episodes for at least one month prior to
      study initiation, and 4) no participation in a regular physical exercise program for at least
      six months prior to study initiation. Exclusion criteria consisted of the presence of
      orthopedic or neurological conditions that would preclude participation in a physical
      exercise program, a history of cardiac arrhythmias, a past history consistent with heart
      disease, diabetes mellitus, arterial hypertension and failure to comply with the research
      protocol.

      Patients were randomly assigned to physical exercise training program PTG, (n=17) or to a
      control group (CG, n=15) without aerobic exercise training by drawing of shuffled, opaque,
      coded envelopes that were opened immediately before starting each case. However, after the
      randomization process, five patients refused to continue and seven interested patients were
      excluded.

      Finally the groups were composed of PTG (n=10) and control group (CG, n=10). Heart rate
      variability (HRV) on rest and during submaximal test was determined by linear analysis (rMSSD
      and SDNN) and nonlinear indices SD1, SD2 and sample entropy (SE). In addition, the
      physiological responses were obtained during cardiopulmonary exercise testing (CPX), the
      walking distance (WD) on six minute walking test and submaximal constant speed testing (CST).
      PTP consisted of 30 minutes of aerobic exercise training on a treadmill, 3 times per week at
      70% of CPX peak speed rate. Patients were evaluated on baseline, 6 and 12 weeks.

      All patients received regular treatment consisting of inhaled bronchodilators and steroids
      and the dosage did not changed during the study. The study protocol was approved by the
      Institutional Ethics Committee and all patients signed a written consent form prior to study
      initiation (109/2006). The target number of patients was calculated to be 10 patients in each
      group, based on a 5% type I error, a 2-sided test, and an 80% power to detect a change
      between the groups in 5 to SD2 at rest. Considering a drop out of 20%, 12 patients in each
      group were calculated. Due to the Gaussian distribution and/or homogeneity of variance in
      variable values, parametric tests were selected for statistical analysis.
    

Intervention name(s): Physical Exercise Training Program Exercise
Intervention type(s): Other
Intervention description(s): Physical Exercise Training Program Exercise training was conducted in three times a week, during 12 weeks at high-intensity targets. Each session consisted of a five minute warm up (walking) at 2 km/h and 30 minutes with an intensity targets set at 70% of the peak speed rate. The increase of intensity was 0.5Km/h when the patient scored less than 4 point of Borg scale (moderate to intense effort) during each session. All evaluations were done at 6th week, in order to analyze the progression of outcomes and exactly adjust the intensity of training.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Health Services Research
Keywords: chronic obstructive pulmonary disease; heart rate variability; physical training