THE ROLE OF GRAVITY IN THE EVOLUTION OF MAMMALIAN BLOOD PRESSURE
Version of Record online: 2 JAN 2014
© 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.
Volume 68, Issue 3, pages 901–908, March 2014
How to Cite
White, C. R. and Seymour, R. S. (2014), THE ROLE OF GRAVITY IN THE EVOLUTION OF MAMMALIAN BLOOD PRESSURE. Evolution, 68: 901–908. doi: 10.1111/evo.12298
- Issue online: 3 MAR 2014
- Version of Record online: 2 JAN 2014
- Accepted manuscript online: 23 OCT 2013 03:38PM EST
- Manuscript Accepted: 19 APR 2013
- Manuscript Received: 4 JAN 2012
- CRW is an Australian Research Council QEII Research Fellow. Grant Number: DP0987626
Understanding of the factors involved in determining the level of central arterial blood pressure in mammals has been clouded by inappropriate allometric analyses that fail to account for phylogenetic relationships among species, and require pressure to approach 0 as body size decreases. The present study analyses systolic, mean arterial, and diastolic blood pressure in 47 species of mammal with phylogenetically informed techniques applied to two-parameter equations. It also sets nonlinear, three-parameter equations to the data to remove the assumption of the two-parameter power equation that the smallest animals must have negligible blood pressure. These analyses show that blood pressure increases with body size. Nonlinear analyses show that mean blood pressure increases from 93 mmHg in a 10 g mouse to 156 mmHg in a 4 tonne elephant. The scaling exponent of blood pressure is generally lower than, though not significantly different from, the exponent predicted on the basis of the expected scaling of the vertical distance between the head and the heart. This indicates that compensation for the vertical distance above the heart is not perfect and suggests that the pressure required to perfuse the capillaries at the top of the body may decrease in larger species.