Respiratory training as strategy to prevent cognitive decline in aging: a randomized controlled trial

Figures & data

Figure 1 Flow diagram to assess the effects of interventions.

Table 1 Baseline demographic and clinical characteristics for each group

	Control (n=22)	Breathing (n=24)	Walking (n=22)	ANOVA
				F(2,65)	P
Female	86.3%	87.5%	68.18%
Age (years)	69.2 (4.8)	65.9 (5.2)	66.2 (5.6)	3.03	0.06
Education (years)	12.9 (2.5)	12.5 (2.9)	12.9 (2.7)	0.13	0.82
MMSE (score)	28.7 (1.5)	28.1 (1.5)	28.8 (1.6)	1.42	0.25

Note: Values are expressed as mean (standard deviation).

Abbreviations: ANOVA, analysis of variance; MMSE, Mini-Mental State Examination.

Table 2 Results of the heart rate at rest, pulmonary parameters and blood analysis

	Control		Breathing		Walking		ANOVA interaction
	Pre	Post	Pre	Post	Pre	Post	F(2,65)	P	ES
HRrest (bpm)	73.3 (68.8, 77.8)	73.9 (69.9, 77.8)	71.5 (67.2, 75.8)	73.9 (70.1, 77.7)	74.0 (69.5, 78.5)	71.2 (67.3, 75.2)	3.14	0.05a	0.88
Erythrocytes (10^−6/mm^3)	4.8 (4.6, 4.9)	4.7 (4.5, 4.9)	4.7 (4.5, 4.8)	4.6 (4.5, 4.8)	5.0 (4.8, 5.1)	4.9 (4.7, 5.0)	0.42	0.65	0.01
Hemoglobin (g/dL)	14.1 (13.6, 14.5)	13.9 (13.4, 14.5)	13.7 (13.3, 14.1)	13.9 (13.4, 14.4)	14.2 (13.7, 14.6)	14.5 (14.0, 15.0)	1.33	0.27	0.03
Hematocrit (%)	41.4 (40.1, 42.6)	41.4 (40.1, 42.7)	41.3 (40.1, 42.5)	41.2 (39.9, 42.4)	42.6 (41.3, 43.9)	42.5 (41.2, 43.9)	0.05	0.95	0.01
SpO2 (%)	95.4 (94.8, 96.0)	95.7 (95.1, 96.2)	95.4 (94.8, 96.0)	96.5 (96.0, 97.1)	95.5 (94.0, 96.1)	96.1 (95.5, 96.7)	2.30	0.11	0.07
MEP (cm/H2O)	81.8 (75.0, 88.6)	83.0 (76.5, 89.6)	84.5 (77.9, 91.0)	92.0 (85.8, 98.3)	93.8 (87.0, 100.6)	99.6 (93.1, 106.2)	4.77	0.01a	0.13
MIP (cm/H2O)	85.6 (76.0, 95.2)	82.1 (73.2, 91.1)	82.7 (73.5, 91.9)	87.5 (78.9, 96.1)	88.1 (78.6, 97.8)	92.3 (83.4, 101.3)	2.99	0.06	0.08
AI axillary fold (cm)	1.17 (0.87, 1.47)	1.22 (0.92, 1.51)	1.56 (1.27, 1.85)	2.02 (1.74, 2.30)	1.24 (0.93, 1.54)	1.51 (1.22, 1.80)	3.57	0.03a	0.10
AI xiphoid process (cm)	1.87 (1.38, 2.37)	2.05 (1.63, 2.46)	2.33 (1.86, 2.81)	2.83 (2.44, 3.22)	2.06 (1.56, 2.55)	2.48 (2.07, 2.89)	2.00	0.14	0.60
AI umbilical scar (cm)	0.35 (-0.01, 0.72)	0.41 (0.06, 0.76)	0.05 (−0.29, 0.40)	0.72 (0.38, 1.05)	−0.02 (−0.39, 0.33)	0.48 (0.13, 0.83)	7.41	0.01a	0.19

Notes:

a Significant differences. Values are expressed as mean (95% CI).

Abbreviations: AI, amplitude index; ANOVA, analysis of variance; CI, confidence interval; ES, effect size; HRrest, heart rate at rest; MEP, maximal expiratory pressure; MIP, maximal inspiratory pressure; SpO₂, oxygen saturation in arterial blood.

Table 3 Results of the cognitive tests and potential confounders

Test	Cognitive domain	Control		Breathing		Walking		ANOVA interaction
		Pre	Post	Pre	Post	Pre	Post	F(2,65)	P	ES
LOGIC_I	Declarative/episodic memory	22.0 (19.7, 24.4)	25.4 (22.7, 28.1)	20.3 (18.0, 22.5)	21.0 (18.5, 23.6)	21.4 (19.1, 23.8)	25.2 (22.5, 27.9)	2.70	0.07	0.08
LOGIC_II	Evocative memory	18.0 (15.7, 20.4)	22.8 (20.2, 25.4)	16.0 (13.8, 18.3)	17.5 (15.0, 20.0)	16.5 (14.2, 18.8)	19.5 (16.9, 22.1)	2.13	0.13	0.06
Vocabulary	Semantic memory	30.1 (27.0, 33.2)	38.5 (34.6, 42.3)	29.0 (26.1, 32.0)	28.3 (24.6, 32.0)	30.6 (27.6, 33.8)	31.8 (27.9, 35.7)	12.60	0.01a	0.28
Information	Semantic memory	16.1 (13.0, 18.3)	17.7 (15.4, 20.0)	14.5 (12.5, 16.7)	16.0 (13.8, 18.2)	16.8 (14.6, 19.0)	17.6 (15.4, 20.0)	0.55	0.57	0.02
DIGITS_F	Short-term memory	5.3 (4.8, 5.8)	5.0 (4.5, 5.5)	5.0 (4.6, 5.5)	5.2 (4.8, 5.8)	5.0 (4.6, 5.6)	4.9 (4.4, 5.4)	2.04	0.14	0.06
DIGITS_B	Mental manipulation	4.7 (4.2, 5.3)	4.1 (3.7, 4.7)	3.8 (3.3, 4.3)	4.2 (3.8, 4.8)	4.0 (3.5, 4.6)	4.1 (3.7, 4.7)	3.76	0.03a	0.11
CORSI_F	Visuospatial memory	4.8 (4.3, 5.3)	4.9 (4.8, 5.3)	4.8 (4.4, 5.3)	5.0 (4.6, 5.5)	4.8 (4.3, 5.3)	4.7 (4.3, 5.2)	0.61	0.54	0.02
CORSI_B	Visuospatial memory	4.3 (3.8, 4.8)	4.3 (3.8, 4.8)	4.3 (3.8, 4.8)	4.0 (3.6, 4.5)	4.7 (4.2, 5.2)	4.5 (4.0, 5.0)	0.26	0.77	0.01
W_Cat	Abstraction	4.6 (3.9, 5.4)	4.0 (3.3, 4.7)	4.1 (3.5, 4.9)	4.8 (4.2, 5.5)	4.5 (3.8, 5.2)	4.6 (4.0, 5.4)	6.01	0.01a	0.16
W_PE	Mental flexibility	5.0 (2.8, 7.3)	6.0 (4.0, 8.0)	5.7 (3.6, 7.9)	3.7 (1.8, 5.7)	4.9 (2.7, 7.1)	5.3 (3.3, 7.4)	4.31	0.02a	0.12
SYMBOLS	Attention	28.4 (25.3, 31.6)	22.0 (19.1, 25.0)	25.9 (22.9, 29.0)	25.7 (22.9, 28.5)	28.8 (25.6, 32.0)	26.3 (23.4, 29.3)	9.38	0.01a	0.22
GDS	Depressive symptoms	9.0 (6.9, 11.1)	9.0 (7.0, 11.1)	6.3 (4.3, 8.4)	5.5 (3.5, 7.5)	7.0 (4.9, 9.1)	7.0 (5.0, 9.1)	1.55	0.22	0.05
STAI	State anxiety	38.9 (34.1, 43.8)	33.5 (29.9, 37.0)	37.6 (33.0, 42.2)	33.6 (30.2, 37.0)	35.1 (30.3, 39.9)	32.5 (29.0, 36.1)	0.37	0.69	0.01
BAECKE	Physical activity	3.7 (2.5, 4.9)	4.0 (2.7, 5.4)	4.2 (3.1, 5.4)	4.3 (3.0, 5.6)	2.7 (1.6, 4.0)	6.1 (4.7, 7.5)	12.0	0.01a	0.27

Notes:

a Significant differences. Values are expressed as mean (95% CI).

Abbreviations: BAECKE, Modified Baecke Questionnaire, for the elderly; CI, confidence interval; CORSI_F, Corsi’s block, forward order; CORSI_B, Corsi’s block, backward order; DIGITS_B, backward digit span; DIGITS_F, forward digit span; ES, effect size; GDS, Geriatric Depression Scale; LOGIC_I, Logic Memory I; LOGIC_II, Logic Memory II; STAI, State-Trait Anxiety Inventory; SYMBOLS, symbol search; W_Cat, number of categories by Wisconsin Card Sorting Test; W_PE, perseverative errors of Wisconsin Card Sorting Test.

Figure S1 Illustration of the exerciser and incentive spirometry

Note: Adapted with permission from the product manual (RESPIRON^®; NCS Ltda, Barueri, SP, Brazil).¹

Figure S2 Instructions for use of the RESPIRON^® (NCS Ltda, Barueri, SP, Brazil).

Notes: Extra instruction: Put adhesive labels on the air intake of cylinders 2 and 3 (front and back). Perform exercises 1–3. Then, remove the adhesive labels and perform exercises 1–6, at level 0.