Effects of 24-hour ambulatory blood pressure monitoring on daily activities

Self-Focused Attention and Mood During Everyday Social Interactions

This study examined the association of dispositional self-focused attention to mood rated at the time of a negative social interaction in 100 employed, middle-age adults using experience sampling methodology. Results revealed that a self-focusing style was associated with higher negative mood and lower positive mood at the time of a negative social interaction during 3 days of everyday activities. Women who were chronically self-focused were particularly vulnerable to these negative social interactions in the daily environment; they were more likely than men to report lower positive mood during the interaction. In addition, 30 minutes after the negative social interaction, self-focused individuals with higher preexisting levels of depressive symptoms continued to report higher levels of negative mood and lower levels of positive mood relative to individuals who were not self-focused and did not report higher depressive symptoms. These results provide support for the role of self-focused attention in the etiology and maintenance of negative moods.

Job control, perceptions of control, and cardiovascular activity: an analysis of ambulatory measures collected over the working day

OBJECTIVE

To assess the influence of job control as a personal characteristic, and momentary perceptions of lack of control, on blood pressure and heart rate monitored over the working day.

METHODS

The study was carried out with a sample of 122 school teachers (45 men, 77 women), divided into high and low job control groups on a standard questionnaire. Blood pressure and heart rate were measured every 20 min using ambulatory techniques, and ratings of concurrent perceived control were also obtained. Energy expenditure was assessed using accelerometers. Cardiovascular measures associated with low perceived control were averaged for each individual, as were readings associated with high perceived control.

RESULTS

Low perceived control ratings were infrequent overall. However, in the participants who reported episodes of both high and low perceived control, systolic and diastolic blood pressure and heart rate were significantly greater during episodes of low control. These effects were independent of concurrent energy expenditure, gender, and time of day. High and low job control groups did not differ in cardiovascular responses to episodes of low perceived control. But low job control was associated with more frequent episodes of low perceived control and fewer periods of high perceived control.

CONCLUSION

The results suggest that laboratory observations concerning the impact of lack of control on cardiovascular activity are corroborated by naturalistic measures in everyday life. Differences in exposure to periods of low perceived control rather than differences in reactivity to uncontrollable situations may contribute to the elevation in cardiovascular risk associated with low job control.

Stress, social support and cardiovascular activity over the working day

The influence of stress on ambulatory blood pressure monitored over the working day, and the potential buffering effect of social support, was assessed in 104 school teachers (37 men and 67 women). Blood pressure and heart rate were measured every 20 min and energy expenditure was assessed using accelerometers. Participants rated the degree of stress they were experiencing at the time of each measurement on a seven-point scale. Episodes of both high and low stress during the working day were reported by 62 participants. They were divided by median split into high and low social support groups on the Interpersonal Support Evaluation List. After controlling for body mass and concomitant energy expenditure, high stress was associated with increased systolic blood pressure, diastolic blood pressure and heart rate. However, the impact of stress was buffered by social support, with no significant increase in blood pressure or heart rate with stress in the high support group. The accelerometers were also shown effectively to discriminate between blood pressure readings taken in the seated and standing positions in terms of energy expenditure. The results corroborate laboratory studies, in showing that social support buffers the impact of episodic stress on cardiovascular activity under naturalistic conditions during the working day.

Ambulatory blood pressure monitoring is associated with reduced physical activity during everyday life

OBJECTIVE

The objective of this study was to assess the impact on noninvasive ambulatory blood pressure monitoring on physical activity measured objectively by use of triaxial accelerometers.

METHODS

Twenty-four working men and women performed ambulatory blood pressure plus activity monitoring for 1 working day and evening and activity monitoring alone for a separate day and evening. Blood pressure measures were taken at 20-minute intervals during the day and 30-minute intervals in the evening and were accompanied by diary assessments of mood, location, and posture. Comparisons were made of energy expenditure on the 2 days and of activity levels during the minutes surrounding each blood pressure reading and diary completion.

RESULTS

Energy expenditure assessed in terms of activity calories per hour was significantly lower during blood pressure plus activity monitoring compared with activity monitoring alone (mean 37.3, SD = 16.3 vs. mean = 43.0, SD = 18.7 kcal, respectively: p = .02). Energy expenditure was lower during the 4 minutes surrounding each blood pressure reading than in the intervals between blood pressure readings. However, energy expenditure was also lower in the intervals between blood pressure readings than during comparable times on the activity only monitoring day. Blood pressure, heart rate, and physical activity were moderately correlated within individuals.

CONCLUSIONS

Ambulatory blood pressure recording using automated sphygmomanometers is associated with reduced physical activity during the monitoring day. This is due partly to regular periods of immobility during cuff inflation and deflation and diary completion and partly to more general self-imposed restrictions on activity. This pattern has implications for the representativeness of ambulatory blood pressure monitoring, and the construction of ambulatory monitoring diaries.

Test-retest reliability of 24-hour ambulatory blood pressures

The test-retest reliability of 24-hour ambulatory blood pressures (ABP) was examined using correlational analyses as well as idiographic and nomothetic time-series regression analyses. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions, each of which was separated by a week. When analyzing the data, various postural positions, activities, and locations were controlled for in order to differentially assess the effects of these variables independently. Correlational analyses found the overall test-retest reliability of the ABPs to be quite good (SBP r = .84-.88, DBP r = .83-.86, HR r = .91-.95). Correlations examined within specific postural positions, activities, and locations were also significant. The time-series regression analyses used confirmed the reproducibility of the ABPs, with no greater than 20% of the subjects showing significant changes in ABPs over the three monitoring periods. Gender effects were also examined. In general, males had significantly higher systolic ABPs overall, although there was no influence of gender in terms of the test-retest reliability of the ABPs.