Changes in six-minute walking distance during pulmonary rehabilitation in patients with COPD and in healthy subjects

Figures & data

Table 1 Anthropometric characteristics and pulmonary function parameters of healthy subjects and patients with chronic obstructive pulmonary disease before and after rehabilitation program

	Healthy subjects (n = 9)		Patients with COPD (n = 26)
	Before RP	After RP	Before RP	After RP
Age, Yr	58 ± 7	–	61 ± 4	–
BMI; kg/m^2	26,52 ± 1.78	25.19 ± 2.13	24.01 ± 5.16	25.18 ± 4.61
FEV1, L	2.94 ± 0.45	2.97 ± 0.56	1.42 ± 0.52***	1.57 ± 0.75†††
FEV1, % Predicted	88.66 ± 9.1	92.50 ± 5.17	48.86 ± 11.31***	51.31 ± 9.73†††
FVC, L	3.16 ± 0.57	3.27 ± 0.51	2.21 ± 0.86***	2.36 ± 0.71†††
FVC, % Predicted	82.75 ± 13.29	85.49 ± 9.41	58.82 ± 9.8***	65.43 ± 7.42†††
FEV1/FVC ratio	82.81 ± 9.5	84.27 ± 10.75	55.64 ± 8.91***	57.91 ± 9.91†††

Unit: Mean ± SD; n, number of subjects.

Notes: Comparisons between patients with COPD and healthy subjects before rehabilitation program:

*** P < 0.001; Comparisons between patients with COPD and healthy subjects after rehabilitation program:

††† P < 0.001.

Abbreviations: COPD, chronic obstructive pulmonary disease; BMI, body mass index; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; RP, rehabilitation program.

Table 2 Exercise characteristics of healthy subjects and patients with chronic obstructive pulmonary disease before and after rehabilitation program

	Healthy subjects (n = 9)		Patients with COPD (n = 26)
	Before RP	After RP	Before RP	After RP
V̇O2peak, mL min^−1 Kg^−1	29.03 ± 6.15	32.6 ± 4.32**	26,27 ± 3.23‡‡	27.54 ± 5.7††§§§
Anaerobic threshold, l min^−1	1.18 ± 0.22	1.38 ± 0.24**	0.84 ± 0.09‡‡‡	1.12 ± 0.05††§§
Dyspnea
Rest	0.2 ± 0.3	0.14 ± 0.23	2.4 ± 1.7‡‡‡	1.4 ± 0.6†††
Peak	3.45 ± 1.12	1.02 ± 1.18**	6.6 ± 1.9‡‡‡	3.3 ± 2.7†††
SO2, %
Rest	96.2 ± 0.2	96 ± 1.3	94 ± 1.24‡‡	93 ± 2.5§§
Peak	95 ± 1.8	96.21 ± 1.5	91 ± 3‡‡‡	92.27 ± 1.3§§§
HR, bat min^−1	156.72 ± 18.9	149.27 ± 18.4**	136 ± 7‡‡‡	137 ± 5††

Unit: mean ± SD; V̇O_2peakl/min.

Notes: Comparison in healthy subjects with values before and after rehabilitation program:

** P ≤ 0.01; Comparison in patients with COPD with values before and after rehabilitation program:

†† P ≤ 0.01,

††† P ≤ 0.001; Comparison between patients with COPD and healthy subjects before rehabilitation program:

‡‡ P ≤ 0.01,

‡‡‡ P ≤ 0.001; Comparison between patients with COPD and healthy subjects after rehabilitation program:

§§ P ≤ 0.01,

§§§ P ≤ 0.01.

Abbreviations: HR, heart rate; SO₂, oxygen saturation; VO_2peak, peak oxygen uptake; COPD, chronic obstructive pulmonary disease; RP, rehabilitation program.

Table 3 Six-minute walking test parameters of healthy subjects and patients with chronic obstructive pulmonary disease before and after rehabilitation program

	Healthy subjects (n = 9)		Patients with COPD (n = 26)
	Before RP	After RP	Before RP	After RP
6MWD, m	600 ± 28.28	789 ± 19.07**	504 ± 55.46‡‡‡	620 ± 69.71††,§§§
6MWD, %	86 ± 4	113 ± 3**	72 ± 8‡‡‡	89 ± 10††,§§§
SO2, %
Rest	96.9 ± 1.13	96.72 ± 1.1	96 ± 2.4	95 ± 2.7
Peak	96.27 ± 1.1	95.45 ± 1.8	91.82 ± 4.5‡‡‡	89 ± 6.5§§§
Dyspnea
Rest	0.18 ± 0.4	0.91 ± 0.3*	0.72 ± 1.27‡‡	0.45 ± 0.47†,§§
Peak	1.72 ± 1.48	0.36 ± 0.5*	4.5 ± 3.033‡‡‡	2.59 ± 2.13†§
HR
Rest	73.72 ± 8.9	65 ± 4.07	75.63 ± 13.87‡‡	76.45 ± 14.03§§
Peak	87.8 ± 12.1	82.27 ± 27.7*	111.09 ± 11.2‡‡	104.81 ± 22.7†,§§§

Unit: Mean ± SD.

Notes: Comparison in healthy subjects with values before and after rehabilitation program,

* P ≤ 0.05,

** P ≤ 0.01; Comparison in patients with COPD with values before and after rehabilitation program,

† P ≤ 0.05,

†† P ≤ 0.01; Comparison between patients with COPD and healthy subjects before rehabilitation program;

‡‡ P ≤ 0.01,

‡‡‡ P ≤ 0.001; Comparison between patients with COPD and healthy subjects after rehabilitation program,

§ P ≤ 0.05,

§§ P ≤ 0.01,

§§§ P ≤ 0.001.

Abbreviations: 6MWD, six-minute walking distance; HR, heart rate; SO₂, oxygen saturation; RP, rehabilitation program.

Figure 1 Logarithmic and linear fitting of the dependant variables for patients with COPD (–♦–) and healthy subjects (---▴---).