Factors Influencing Human Blood Pressure and Heart Rate in Clinical Health Germaine Cornelissen1, Kuniaki Otsuka2, Yoshihiko Watanabe3, Jarmila Siegelova4, Lyazzat Gumarova5, Vincenzo Valenzi6 (presenter), for Investigators of the Project on the BIOsphere and the COSmos (BIOCOS) 1 Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA; 2 Executive Medical Center, Totsuka Royal Clinic, Tokyo Women's Medical University, Tokyo, Japan; 3 Women’s Medical University, Tokyo, Japan; 4 Masaryk University, Brno, Czech Republic; 5 Al-Farabi Kazakh National University, Almaty, Kazakhstan; 6 University of Rome, Rome, Italy

AIM To review the relative influence of several factors on human blood pressure (BP) and heart rate (HR), with emphasis on their circadian rhythm.

Genetics The circadian amplitude of BP was found to be larger in students with a positive family history of high BP than in students with a negative such family history. Similar results were found in newborns.

Genetics The circadian and circaseptan amplitudes of HR were shown to be inherited.

Exercise and Rest-Activity Cycle BP and HR are known to physiologically respond to exercise. Their response, however, may differ depending on when exercise is performed.

Exercise and Rest-Activity Cycle Apart from the circadian stage-dependent effects of exercise, exercise in the evening but not in the morning may also be associated with an increase in the circadian amplitude of BP.

Exercise and Rest-Activity Cycle Regular daily activities have long been regarded as determining the circadian variation in BP. The circadian BP rhythm persists, however, during continued bedrest. Concomitantly monitoring BP and activity around the clock for 6-7 days in clinical health shows no phase lag of BP versus activity, suggesting that activity is not the determinant of the circadian rhythm in BP.

Exercise and Rest-Activity Cycle Whereas BP and HR are usually lower during sleep and higher during the active part of the day, BP can be higher during the night in some patients with Type2 diabetes suffering from autonomic nervous dysfunction. Fasting Glucose HR variability

Meals, Salt and Alcohol Increases in both BP and HR have been noted after a meal, from newborns to adulthood. Population-mean cosinor spectrum of HR of 164 newborns fed every 3 hours. A 4-hour spectral peak was found instead in another population of babies fed every 4 hours. Similar results apply to BP measured at the same times. In a population of healthy Japanese nurses following the same schedule of 3 daily meals, increases in BP and HR are observed after each meal. 90% Prediction Limits (44 women in Nov & 50 in Jun) Nov Jun

Meals, Salt and Alcohol Salt intake is associated with an increase in BP in salt-sensitive individuals. Two independent studies have identified individuals who respond to salt restriction with an increase in BP. Whether such an opposite behavior was the result of day- to-day variability in circadian characteristics remains to be clarified since the latter can be quite large.

Meals, Salt and Alcohol A small cross-over study suggests that the effect of salt intake is also circadian stage-dependent.

Meals, Salt and Alcohol Alcohol intake has been consistently associated with an increase in the circadian amplitude of BP.

Meals, Salt and Alcohol Alcohol intake has been consistently associated with an increase in the circadian amplitude of BP.

Smoking In clinically healthy men and women between 40 and 59 years of age, smoking was found to be associated with a statistically significant increase in the MESOR of systolic BP and with numerically larger circadian amplitudes of diastolic BP and of HR in subjects with a positive family history of high BP, but not in subjects with a negative such family history.

Emotions Emotions can have a larger impact on BP than other factors such as exercise, alcohol or tobacco use.

Space Weather HR has been shown to increase in association with magnetic storms, whereas HR variability was decreased. The effect is thought to underlie excess mortality from myocardial infarction. Geomagnetic storms are associated with a decrease in HRV.

Discussion & Conclusion Longitudinal around-the-clock physiologic monitoring, facilitated by the availability of miniaturized sensors and advances in communication, can provide useful information for health maintenance and disease risk assessment. A chronobiologic assessment of the data thus collected can help screen for abnormalities in circadian rhythm characteristics before disease becomes overt by screening for vascular variability disorders (VVDs). VVDs have been associated with adverse outcomes in several outcome studies.

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