Cardiovascular Adjustments to Gravitational Stress

Abstract

The sections in this article are: 1 Hydrostatic Pressure 1.1 Models 1.2 Hydrostatic Indifference Point 1.3 Transmural Pressure and Tissue Filtration 2 Immediate Cardiovascular Responses to Posture Changes and Blood Volume Redistribution 2.1 Experimental Conditions 2.1.1 Lower-Body Negative Pressure 2.1.2 Passive Tilt 2.1.3 Immersion 2.1.4 G-Suit Devices 2.1.5 Lower-Body Positive Pressure 2.2 Blood Volume and Distribution 2.3 Intravascular and Intracardiac Pressures 2.4 Cardiac Dimensions and Pump Performance 2.5 Cardiac Output 2.6 Regional Flow 2.6.1 Brain 2.6.2 Myocardium 2.6.3 Skin and Muscle 2.6.4 Splanchnic Region 2.6.5 Kidneys 2.7 Postural Effects on Hemodynamic Responses to Exercise 2.8 Dynamic Responses to Posture Changes 2.8.1 Regulatory Mechanisms 2.8.2 Systemic Responses 3 Cardiovascular Adaptation to Prolonged Bed Rest, Zero Gravity, and Related Conditions 3.1 Experimental Conditions 3.1.1 Bed Rest 3.1.2 Head-Down Tilt 3.1.3 Immersion 3.1.4 Zero Gravity 3.2 Body Composition 3.3 Blood Volume 3.4 Cardiovascular Function 3.4.1 Maximal Oxygen Uptake 3.4.2 Cardiac Dimensions and Performance 3.4.3 Systemic Hemodynamics 3.4.4 Orthostatic Intolerance 3.5 Dynamic Responses 4 Hypergravic Conditions 4.1 Experimental Conditions 4.2 Fluid Shifts 4.3 Cardiac Dimensions and Performance 4.4 Cardiac Output and Regional Flow 4.4.1 Pulmonary Blood Flow 4.4.2 Brain 4.4.3 Splanchnic and Muscle Blood Flow 4.5 Dynamic Responses and Reflex Adjustments