Masked hypertension is “unmasked” by low-intensity exercise blood pressure

Figures & data

Table I. Clinical characteristics of study population (n = 75).

Variable	Normotensive with exaggerated BP response to exercise (n = 33) Mean ± SD or %	Masked hypertensive (n = 42) Mean ± SD or %	p-value
Age (years)	53.7 ± 8.0	53.7 ± 9.0	0.98
Sex (% male)	27.3	73.8	<0.001
Height (cm)	168.4 ± 10.0	173.7 ± 8.6	<0.05
Weight (kg)	84.3 ± 17.5	89.5 ± 14.8	0.17
BMI (kg/m^2)	29.7 ± 5.2	29.6 ± 3.9	0.93
Day SBP (mmHg)	126 ± 5	143 ± 8	<0.001
Day DBP (mmHg)	77 ± 5	85 ± 8	<0.001
Night SBP (mmHg)	112 ± 10	121 ± 11	<0.001
Night DBP (mmHg)	66 ± 7	71 ± 9	<0.05
ABPM SBP (mmHg)	124 ± 4	139 ± 7	<0.001
ABPM DBP (mmHg)	75 ± 5	82 ± 7	<0.001
Resting heart rate (beats/min)	66.0 ± 10.1	66.5 ± 8.2	0.81
Total cholesterol (mmol/l)	5.20 ± 0.99	5.37 ± 0.90	0.45
HDL-cholesterol (mmol/l)	1.41 ± 0.36	1.28 ± 0.42	0.17
LDL-cholesterol (mmol/l)	3.20 ± 0.95	3.38 ± 0.84	0.39
Triglycerides (mmol/l)	1.30 ± 0.58	1.86 ± 1.49	<0.05
Plasma glucose (mmol/l)	5.42 ± 0.71	6.70 ± 2.83	<0.05
Glycosylated HbA1c (%)	5.62 ± 0.47	6.35 ± 1.60	<0.05
Current smoker (%)	9.1	7.1	0.76
Aortic PWV (m/s)^a	7.53 ± 1.69	8.86 ± 2.06	<0.05
Brachial PWV (m/s)^a	7.69 ± 1.11	8.61 ± 1.13	<0.05

Data are mean ± SD. BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; ABPM, 24-h ambulatory blood pressure monitor; HDL, high-density lipoprotein; LDL, low-density lipoprotein; PWV, pulse wave velocity. ^aAnalysis of covariance (ANCOVA) corrected for mean arterial pressure.

Table II. Hemodynamic differences between normotensives with exaggerated blood pressure (BP) response to exercise and masked hypertensive individuals.

Variable	Condition	Normotensive with exaggerated BP response to exercise (n = 33) Mean (SD)	Masked hypertensive (n = 42) Mean (SD)	p-value	ANCOVA, p-value^a
SBP (mmHg)	Rest	120 ± 9	127 ± 9	<0.001	–
	Light exercise	168 ± 15	188 ± 22	<0.001	<0.05
DBP (mmHg)	Rest	71 ± 6	74 ± 7	0.080	0.73
	Light exercise	82 ± 9	85 ±11	0.118	0.46
MAP (mmHg)	Rest	88 ± 6	92 ± 7	<0.05	0.94
	Light exercise	114 ± 10	120 ± 14	<0.05	0.17
Heart rate (beats/min)	Rest	66 ± 10	67 ± 8	0.805	0.70
	Light exercise	111 ±9	109 ± 10	0.559	0.47

Data are mean ± SD. SBP, systolic blood pressure; DBP, Diastolic blood pressure; MAP, mean arterial pressure; PWV, pulse wave velocity; ^aAnalysis of covariance (ANCOVA) corrected for supine resting brachial SBP.

Figure 1. Change in systolic blood pressure (SBP) from rest to light exercise (60–70% maximum heart rate, HR_max) for the study population (n = 75). Values are significantly different between normotensives with exaggerated BP response to exercise and masked hypertensives and remain significant after analysis of covariance (ANCOVA) correction for height, sex, fasting triglycerides and plasma glucose levels. *p < 0.05. Error bars are standard error of the mean.

Figure 2. Pearson correlation graph showing the relationship between 24-h ambulatory systolic blood pressure (SBP) and light exercise brachial SBP in the study population (n = 75).

Table III. Logistic regression model for predictors of masked hypertension.

					95% CI for OR
Variable	B	Wald	p-value	Odds ratio	Upper	Lower
Light exercise SBP	0.065	5.92	0.015	1.067	1.124	1.013
Sex	2.391	7.34	0.007	10.92	61.61	1.938
Aortic PWV	0.925	5.21	0.023	2.521	5.578	1.139
Total cholesterol	0.785	2.56	0.110	2.192	5.732	0.838
Fasting glucose	0.575	1.39	0.239	1.777	4.628	0.682
Age	−0.061	1.20	0.273	0.941	1.050	0.843
BMI	−0.076	0.64	0.423	0.926	1.117	0.768
Triglycerides	−0.304	0.25	0.615	0.738	2.411	0.226
Resting SBP	0.034	0.53	0.466	1.034	1.132	0.945

CI, confidence interval; OR, odds ratio; SBP, systolic blood pressure; PWV, pulse wave velocity; BMI, body mass index.