[Effects of nighttime and daytime interval definition on blood pressure and dipping in patients referred for ambulatory blood pressure measurement]

On the use of actigraphy in clinical evaluation of diurnal blood pressure profile

A disturbed diurnal blood pressure profile is one of the most important risk factors of cardiovascular diseases. This review analyzes the use of simultaneous diurnal ambulatory blood pressure monitoring (ABPM) and motion activity monitoring (actigraphy) to obtain additional information for correct interpretation of ABPM results in clinically significant decision-making. The article considers practical aspects of actigraphy in expert ABPM for clock-independent calculation of the parameters of nighttime and daytime blood pressure (BP); detection of BP changes during sleep; connection with respiratory disturbances during sleep, motion activity, and body position; and sleep deprivation in shift workers. Original illustrations of simultaneous ABPM and actigraphy are provided.

Association of self-reported sleep and hypertension in non-insomniac elderly subjects

OBJECTIVES

Sleep duration and sleep quality play important roles in the development of hypertension (HT) in middle-aged subjects, with controversial data in elderly. In this study, we investigated the link between HT and self-reported sleep in non-insomniac elderly subjects.

METHODS

We examined 500 participants without insomnia complaints aged 72 ± 1 years. An extensive instrumental evaluation was carried out, including 24-h blood pressure (BP) monitoring and an assessment of nocturnal BP dipping. Sleep duration and quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI). The subjects were stratified into three groups according to sleep duration: short (< 6 h), normal (> 6h to < 8 h), and long (> 8 h) sleepers. A PSQI < 5 defined good sleepers (GS, n = 252), and a PSQI > 5 (n = 248) defined poor sleepers (PS).

RESULTS

PS represented 50% of the subjects, more frequently females. Compared to GS, PS did not differ in terms of HT, BP, baroreflex sensitivity (BRS), and BP dipping. Short, normal, and long sleepers accounted for 28%, 42%, and 30% of subjects, with HT, BP values, BRS, and gender not differing between groups. No relationship was found between nocturnal BP values and self-reported sleep measures. Logistic regression analysis indicated that neither sleep duration nor sleep quality predicts the prevalence of HT, the body mass index being the only factor affecting this association.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT00759304 and NCT00766584.

CONCLUSIONS

In a sample of non-insomniac elderly subjects, neither sleep duration nor sleep quality affected the prevalence of HT. These data argue against a relationship between self-reported sleep duration and quality and HT in elderly without insomnia.

Step count is associated with lower nighttime systolic blood pressure and increased dipping

BACKGROUND

Higher nighttime blood pressure (BP) and the loss of nocturnal dipping of BP are associated with an increased risk for cardiovascular events. However, the determinants of the loss of nocturnal BP dipping are only beginning to be understood. We investigated whether different indicators of physical activity were associated with the loss of nocturnal dipping of BP.

METHODS

We conducted a cross-sectional study of 103 patients referred for 24-hour ambulatory monitoring of BP. We measured these patients' step count (SC), active energy expenditure (AEE), and total energy expenditure simultaneously, using actigraphs.

RESULTS

In our study population of 103 patients, most of whom were hypertensive, SC and AEE were associated with nighttime systolic BP in univariate (SC, r = -0.28, P < 0.01; AEE, r = -0.20, P = 0.046) and multivariate linear regression analyses (SC, coefficient beta = -5.37, P < 0.001; AEE, coefficient beta = -0.24, P < 0.01). Step count was associated with both systolic (r = 0.23, P = 0.018) and diastolic (r = 0.20, P = 0.045) BP dipping. Nighttime systolic BP decreased progressively across the categories of sedentary, moderately active, and active participants (125mm Hg, 116mm Hg, 112mm Hg, respectively; P = 0.002). The degree of BP dipping of BP increased progressively across the same three categories of activity (respectively 8.9%, 14.6%, and 18.6%, P = 0.002, for systolic BP and respectively 12.8%, 18.1%, and 22.2%, P = 0.006, for diastolic BP).

CONCLUSIONS

Step count is continuously associated with nighttime systolic BP and with the degree of BP dipping independently of 24-hour mean BP. The combined use of an actigraph for measuring indicators of physical activity and a device for 24-hour measurement of ambulatory BP may help identify patients at increased risk for cardiovascular events in whom increased physical activity toward higher target levels may be recommended.