321435_Print.indd

(やまだぃちぅ) #1

women has evolved differently than in men, primarily due to their monthly ovu-


latory cycle and the need to retainfluid volume for uterine egg implantation. This


hidden adaptation makes their blood pressure less sensitive to dietary salt and tends


to protect them from cardiovascular insults during their reproductive years. Finally,


there is also a venous blood pressure adaptation in humans, made necessary as we


became bipedal. The soleus muscle pump which is initiated by neuronal signals


from Meissner’s corpuscles located on the plantar surface of the foot generates the


added venous blood pressure needed to counteract the effects of gravity on the 70–


75% of blood volume that is below the heart when humans stand.


A large part of this discussion has been focused on the functional aspects of


blood pressure, as it occurs in relation to how people in Western societies behave. It


is highly likely that the blood pressure and underlying hormonal responses to the


different physical and cultural environmental circumstances in non-Western pop-


ulations will be different, although surprisingly, there are relatively few studies of


ambulatory blood pressure and behavior in these populations. Thus, for example,


the examination of sociological roles on circadian blood pressure patterns as I have


described them here is likely idiosyncratic and ethnocentric to the populations


studied. However, there have been studies in migrant populations such as Filipinos


living in Hawaii (see Brown, this volume).


Finally, there are“hidden”physiological adaptations in populations that relate to
climate that might also affect the“hidden”blood pressure adaptations noted in the


current discussion (James 2013 ). Readers interested in these should consult James


and Baker ( 1995 ) or James ( 2013 ). However, suffice it to say that all physiology is


integrated, so that the blood pressure responses to thermal, postural, dietary,


reproductive, and physical stressors are interrelated. One might say that this


interconnectedness is also part of the“hidden adaptability”of blood pressure.


Acknowledgments Some of the data reported were collected from studies supported by NIH
Grants HL37054, HL47540, and CA72457.


References


Angeli, F., Reboldi, G., & Verdecchia, P. (2010). Masked hypertension: Evaluation, prognosis,
and treatment.American Journal of Hypertension, 23, 941–948.
Arifuddin, M. S., Hazari, M. A. H., & Reddy, B. R. (2012). Blood pressure variations during different
phases of the menstrual cycle.International Journal of Science & Nature, 3(3), 551–554.
Baumgart, P., Walger, P., Fuchs, G., Dorst, K. G., Vetter, H., & Rahn, K. H. (1989). Twenty-four
hour blood pressure is not dependent on endogenous circadian rhythm. Journal of
Hypertension, 7, 331–334.
Blank, S. G., Mann, S. J., James, G. D., West, J. E., & Pickering, T. G. (1995). Isolated elevation
of diastolic blood pressure: Real or artifact?Hypertension, 26, 383–389.
Blank, S. G., West, J. E., Muller, F. B., Cody, R. J., Harshfield, G. A., Pecker, M. S., et al. (1988).
Wideband external pulse recording during cuff deflation: A new technique for evaluation of the
arterial pressure pulse and measurement of blood pressure.Circulation, 77, 1297–1305.


164 G.D. James

Free download pdf