Acute exercise-induced catecholaminergic responses after 16 weeks of community-based exercise training in early-stage breast cancer survivors

Table 1 Participant characteristics before and after a 16-week community-based exercise training program, mean (SD) or n (%)

	BCS (n = 13)		CON (n = 13)		P values
	PRE	POST	PRE	POST	G × P	Group	Phase
Age (year)	57 (9)		58 (7)			0.658
Race (white)	13 (100)		13 (100)			1.000
Ethnicity (non-Hispanic)	13 (100)		12 (92.3)			0.308
Education (college degree)	12 (92.3)		13 (100)			0.288
Employment status (employed)	8 (61.5)		12 (92.3)			0.135
Marital status (married)	8 (61.5)		8 (61.5)			0.790
Height (cm)	164.5 (9.0)		162.7 (5.5)			0.724
Body mass (kg)	69.8 (8.6)	70.0 (8.3)	72.3 (19.5)	72.7 (20.8)	0.737	0.751	0.549
Lean mass (kg)	38.7 (3.7)	40.0 (3.0)	41.2 (9.4)	40.7 (10.6)	0.083	0.680	0.388
Body fat (%)	40.9 (7.2)	39.2 (6.4)	39.2 (4.4)	40.4 (5.2)	0.053	0.949	0.546
Lean mass (%)	55.9 (6.8)	57.7 (6.0)	57.6 (3.9)	56.5 (4.7)	0.030a	0.947	0.625
Epinephrine (pg∙mL-1)	12.5 (11.6)	15.0 (15.9)	23.5 (12.0)	20.3 (30.2)	0.999	0.447	0.899
Norepinephrine (pg∙mL-1)	565.6 (295.2)	467.4 (305.9)	653.6 (403.4)	679.0 (322.2)	0.162	0.671	0.610

^aP < 0.05, interaction effect [breast cancer survivor (BCS) vs non-cancer control (CON)].

Independent samples t-tests and χ² tests compared characteristic differences between BCS and CON. BCS: Breast cancer survivor; CON: Non-cancer control; PRE: Pre-training; POST: Post-training; G × P: Group × phase interaction.

Table 2 Clinical characteristics of breast cancer survivors, mean (SD) or n (%)

	BCS (n = 13)
Time from last treatment (day)	82 (90)
Time from surgery (day)	224 (115)
Time from radiation (day)	62 (78)
Time from chemotherapy (day)	152 (100)
Stage
I	5 (38)
II	6 (46)
III	2 (15)
Tumor status
ER+ positive	12 (92)
PR+ positive	12 (92)
HER2+ positive	4 (31)
ER-/PR-/HER2-	1 (8)
Pre-menopausal	5 (38)
Post-menopausal	8 (62)

BCS: Breast cancer survivor; ER: Estrogen-receptor; PR: Progesterone-receptor; HER2: Human epidermal growth factor receptor 2.

Table 3 Physiological responses to VO₂peak test and acute, intermittent exercise before and after training, mean (SD)

	BCS (n = 13)		CON (n = 13)		P values
	PRE	POST	PRE	POST	G × P	Group	Phase	g
CPET
VO2peak (mL∙kg-1∙minute-1)	21.4 (6.6)	22.3 (5.6)	22.5 (2.8)	23.6 (4.5)	0.860	0.523	0.164	-0.04
Peak HR (bpm)	160 (18)	160 (17)	157 (10)	158 (12)	0.830	0.709	0.910	-0.07
Peak power output (W)	119 (34)	137 (40)	129 (21)	136 (24)	0.050a	0.713	< 0.001b	0.34
Duration (second)	596 (127)	669 (142)	617 (85)	647 (154)	0.236	0.928	0.006b	0.31
Acute Exercise Trial
Resistance (W)	74 (20)	83 (24)	77 (16)	82 (82)	0.194	0.848	< 0.001b	0.07
Average RPE	14 (3)	13 (1)	13 (1)	14 (1)	0.070	0.709	0.588	-0.97
average HR (bpm)	136 (8)	136 (7)	135 (8)	145 (9)	0.139	0.166	0.149	-1.20

^aP = 0.05, interaction effect [breast cancer survivor (BCS) vs non-cancer control (CON)].

^bP < 0.05, effect of phase [post-training (POST) vs pre-training (PRE)].

A linear mixed model using a group (BCS vs CON) × training (PRE vs POST) approach was taken to assess training-induced changes. BCS: Breast cancer survivor; CON: Non-cancer control; PRE: Pre-training; POST: Post-training; CPET: Cardiopulmonary exercise test; VO₂peak: Peak oxygen uptake; G × P: Group × phase interaction; g: Hedge’s g effect sizes with thresholds set at 0.16 (small), 0.38 (medium), and 0.76 (large).

Table 4 Correlation matrix between exercise-induced responses in catecholamines and immune cells before and after training

Catecholamines	Response phase	Immune cell type	r	r2	95%CI	P value
Epinephrine (pg∙mL-1)	Initiation	Lymphocyte mobilization	0.34	0.11	(0.07-0.56)	0.016a
	Recovery	Lymphocyte egress	0.38	0.14	(0.11-0.59)	0.007a
	Initiation	MAIT cell mobilization	0.10	0.01	(-0.20 to 0.38)	0.506
	Recovery	MAIT cell egress	0.13	0.02	(-0.18 to 0.41)	0.413
	Initiation	Neutrophil mobilization	0.11	0.01	(-0.18 to 0.38)	0.467
	Recovery	Neutrophil egress	0.16	0.03	(-0.13 to 0.43)	0.278
Norepinephrine (pg∙mL-1)	Initiation	Lymphocyte mobilization	0.53	0.28	(0.29-0.70)	0.001a
	Recovery	Lymphocyte egress	0.47	0.22	(0.22-0.66)	0.001a
	Initiation	MAIT cell mobilization	0.16	0.03	(-0.14 to 0.43)	0.300
	Recovery	MAIT cell egress	0.21	0.05	(-0.09 to 0.48)	0.166
	Initiation	Neutrophil mobilization	0.54	0.30	(0.31-0.72)	0.001a
	Recovery	Neutrophil egress	0.19	0.03	(-0.11 to 0.45)	0.219

^aP ≤ 0.05 significant correlation (r).

Pearson’s correlations were assessed to investigate the association between training-induced changes in catecholaminergic and immune cell responses post-exercise. r: Pearson’s r with thresholds set at weak (< 0.40), moderate (0.40-0.69), and strong (≥ 0.70); r²: Coefficient of determination; MAIT: Mucosal-associated invariant T-cells.