Interoceptive awareness in essential hypertension

Objective: Clinical practice and research provide evidence indicating the involvement of psychological factors in essential hypertension. Little is known about interoception (i.e. the ability of perceiving bodily signals) in essential hypertension. The present study focused on the assessment of interoceptive awareness in newly diagnosed-untreated hypertensives by means of ambulatory blood pressure monitoring (ABPM), a useful tool in the detection and evaluation of hypertension.

Methods: The study population consisted of 50 untreated newly diagnosed hypertensives (48.3±9.7years) and 31 normotensives (49.5±14.2years) matched regarding sex, BMI and prevalence of smoking. All participants underwent 24-hour ABPM (Spacelabs 90207). Cardiac interoceptive awareness was assessed by means of a heartbeat detection task.

Results: Hypertensives exhibited higher office blood pressure (BP) and heart rate (HR) levels (clinic systolic BP: 152±20 vs 140±17; p=0.01, clinic diastolic BP: 95±10 vs 89±11; p=0.008, clinic HR: 82±13 vs 74±11; p=0.04) as well as ambulatory measurements (systolic BP24: 137±11 vs 119±7; p<0.001, diastolic BP24: 87±7 vs 73±5; p<0.001, HR24: 79±9 vs 71±10; p<0.01) compared to normotensives. Moreover, the analysis revealed an increased interoceptive awareness in hypertensives as compared to normotensives. A comparison within the hypertensive group between subjects with and without interoceptive awareness revealed that subjects with increased interoceptive awareness had higher office systolic and diastolic blood pressure values, as well as mean ambulatory HR.

Conclusion: These findings give credence to the idea that interoceptive awareness may represent an enhanced cardiovascular reactivity involved in essential hypertension, even in its early stages. The cross-sectional nature of this study precludes causal inference, but provides valuable directions for future prospective investigations.