Adrenaline during mental stress in relation to fitness, metabolic risk factors and cardiovascular responses in young men

Figures & data

Table I. Group characteristics.

Variable	Screening BP		p
	⩾140/90 mmHg (n = 19)	⩽115/75 mmHg (n = 19)
Age (years)	22.2 (21–23)	22.6 (22–24)
Body mass index (kg/m^2)	25.8 (4.8)	23.0 (2.6)	0.03
Waist circumference (cm)	92.4 (11.5)	85.1 (7.6)	0.03
Systolic BP (mm Hg)	130 (10)	115 (8)	<0.0001
Diastolic BP (mm Hg)	80 (8)	68 (10)	0.0003
Pulse rate (beats/min)	67 (11)	63 (9)	0.16
Total cholesterol (mmol/l)	4.2 (0.7)	4.2 (0.7)	0.67
HDL (mmol/l)	1.2 (0.3)	1.2 (0.2)	0.71
Triglycerides (mmol/l)	1.6 (2.4)	0.8 (0.4)	0.22
Glucose (mmol/l)	5.0 (0.4)	4.8 (0.3)	0.14
Insulin (pmol/l)	50.4 (42)	34.6 (11)	0.42
GDR/I (AU)	1.9 (1.2)	2.3 (0.8)	0.20
Peak oxygen uptake (ml/min/kg)	45.8 (8.5)	48.3 (5.2)	0.29

Mean values (SD). Age not compared statistically (range in parenthesis).

BP, blood pressure; HDL, serum high‐density lipoprotein cholesterol; GDR/I, insulin‐adjusted glucose disposal rate; AU, arbitrary units.

Table II. Plasma catecholamine and cardiovascular responses to mental stress.

	Baseline and glucose clamp		Mental stress test		Recovery
	H	N	H	N	H	N
Adrenaline (pmol/l)	224 (183)	163 (78)	376 (303)^d	228 (128)^b	225 (158)^c	173 (106)^a
Noradrenaline (nmol/l)	1.17 (0.41)	0.94 (0.32)	1.57 (0.66)^c	1.14 (0.40)^c	1.41 (0.57)^a	1.21 (0.49)
Heart rate (ms)	61 (9)	59 (8)	78 (10)^d	70 (12)^d	66 (9)^d	63 (9)^d
ΔSBP (mm Hg)			15.5 (15.8)	8.6 (11)
ΔDBP (mm Hg)			10.4 (10.8)	3.7 (6.1)

Mean values (SD).

H, high screening blood pressure; N, normal screening blood pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure.

^ap<0.05, ^bp<0.01, ^cp<0.001, ^dp<0.0001 vs. previous measurement. p<0.0001 for effects by repeated measures analysis, except adrenaline (p<0.01), SBP (p<0.001), and DBP (p<0.05) in N. p = 0. 06 for group difference in Δadrenaline and stress adrenaline level; Δnoradrenaline, stress noradrenaline level and heart rate, and ΔDBP significantly higher in H (all p<0.05).

Table III. Correlations between plasma adrenaline and peak oxygen uptake and measures of obesity in the combined groups.

Variable	Plasma adrenaline
	Abas		ln Arest		ln Amst		ln Amax		ΔA		ln Arec
	rs	p	r	p	R	p	r	p	rs	p	r	p
VO2peak	0.18	NS	0.40	<0.05	0.47	<0.01	0.49	<0.01	0.38	<0.05	0.29	NS
ln BMI	−0.38	<0.05	−0.44	<0.01	−0.36	<0.05	−0.36	<0.05	−0.20	NS	−0.32	NS
ln WC	−0.33	<0.05	−0.39	<0.05	−0.37	<0.05	−0.38	<0.05	−0.29	NS	−0.27	NS

A, adrenaline; A_bas, baseline (before glucose clamp); A_rest, mean resting value; A_mst mean value during mental stress test; A_max, maximal value (individual); ΔA, change from mean resting value; A_rec, recovery; ln, natural logarithm; r_s, Spearman's rank correlation coefficient; VO_2peak, peak oxygen uptake; BMI, body mass index; WC, waist circumference.

Table IV. Stepwise multiple regression analyses with plasma adrenaline as the dependent variable.

Explanatory variables	Plasma adrenaline
	Rest		Mental stress		Response (Δ)
	β	p	β	p	β	p
High screening blood pressure	0.37	<0.05	0.40	<0.01	0.38	<0.05
Body mass index	−0.56	<0.001		NS		NS
Peak oxygen uptake		NS	0.54	<0.001	0.46	<0.01

β, standardized regression coefficient.

All models adjusted for waist circumference and smoking status; the response also adjusted for resting value (all non‐significant).

Figure 1. Correlations between peak oxygen consumption and mean plasma adrenaline at rest (top left) and during mental stress test (MST) (top right), maximal level during MST (bottom left), and the response (bottom right). Filled circles and solid regression line: men with high (H) screening blood pressure; open circles and dashed regression line: men with normal (N) screening blood pressure. r_s, Spearman's rank correlation coefficient. Correlations in H still significant after exclusion of the subject with the lowest peak oxygen consumption for mean (r = 0.59, p<0.05) and maximal (r = 0.66, p<0.01) adrenaline level during MST and for the response (r_s = 0.57, p<0.05).

Figure 2. Correlations between body mass index and mean plasma adrenaline at rest (top) and during mental stress test (MST) (bottom). Filled circles and solid regression lines: men with high (H) screening blood pressure; open circles and dashed regression lines: men with normal (N) screening blood pressure.

Table V. Correlations between plasma adrenaline and serum lipids and variables of glucose metabolism in the combined groups.

Variable	Plasma adrenaline
	Abas		ln Arest		ln Amst		ln Amax		ΔA		ln Arec
	rs	p	r/rs	p	r/rs	p	r/rs	p	rs	p	r/rs	p
Total cholesterol	−0.46	<0.01	−0.38	<0.05	−0.26	NS	−0.28	NS	−0.05	NS	−0.32	<0.05
HDL	0.39	<0.05	0.48	<0.01	0.55	<0.001	0.52	<0.001	0.32	<0.05	0.39	<0.05
Triglycerides^a	−0.38	<0.05	−0.30	NS	−0.34	<0.05	−0.39	<0.05	−0.21	NS	−0.09	NS
Glucose	−0.31	NS	−0.28	NS	−0.17	NS	−0.16	NS	0.03	NS	−0.18	NS
Insulin^a	−0.18	NS	−0.26	NS	−0.23	NS	−0.27	NS	−0.13	NS	−0.16	NS
GDR/I	0.11	NS	0.21	NS	0.25	NS	0.30	NS	0.19	NS	0.01	NS

A, adrenaline; A_bas, baseline (before infusion), A_rest, mean resting value, A_mst mean value during mental stress test, A_max, maximal value (individual); ΔA, change from mean resting value; A_rec, recovery; HDL, serum high‐density lipoprotein cholesterol; GDR/I, insulin‐adjusted glucose disposal rate.

^aSpearman's rank correlation coefficients (r_s).

Figure 3. Correlations between mean plasma adrenaline level at rest (left) and during mental stress test (MST) (right) and serum high‐density lipoprotein cholesterol (HDL). Filled circles and solid regression line: men with high (H) screening blood pressure; open circles and dashed regression line: men with normal (N) screening blood pressure.