Inactivity: Physiological Effects

Inactivity: Physiological Effects describes the physiological deconditioning inherent in inactivity and immobilization. This book is organized into eight chapters that review the body of information from studies on healthy volunteers conducted in direct support of the space program. Considerable chapters are devoted to the changes occurring in the cardiovascular system, bone and muscle, metabolism and endocrine responses, psychosocial responses, and exercise tolerance. Other chapters discuss the clinical effects and clinical management of deterioration while indicating the changes that have been found in health, normal bed rested subjects. The remaining chapters explore the data on crews that have flown in since their physiological responses are qualitatively similar to those observed in bed rested subjects or immobilized patients on earth. Clinicians, nursing staff, physiologists, researchers, and students in the field will find this book invaluable.

Foreword

Preface

1 Introduction

I. Entry into the Space Age

II. Ground-Based Simulations of Weightlessness

III. Effects of Inactivity

IV. The Effects of Gravity

V. Summary

References

2 Cardiovascular Effects of Inactivity

I. The Impact of Gravity

II. Levels of Defense in Body Position Changes

III. The Gauer-Henry Reflex

IV. Cardiovascular Responses to Inactivity and Immobilization

V. Stress Test Responses following Inactivity

VI. Cardiovascular Changes with Weightlessness

VII. Management of Cardiovascular Effects of Inactivity

VIII. Clinical Applications

References

3 Effects of Inactivity on Bone and Calcium Metabolism

I. Current Concepts of Skeletal Metabolism

II. Current Concepts in Calcium Metabolism

III. Negative Calcium Balance during Bed Rest

IV. Changes in Blood Chemistries during Bed Rest

V. Intestinal Calcium Absorption during Bed Rest

VI. Renal Excretion of Calcium during Bed Rest

VII. Influence of Age and Sex on Calciuria

VIII. The Effect of Bed Rest on Bone Density

IX. Effects of Immobilization on Bone Composition and Structure

X. Effects of Exercise on Bone Loss during Bed Rest

XI. Bone Loss during Spaceflight

XII. Bone Changes in "Bed Rested" Animal Models

XIII. Summary

Reference

4 Effects of Inactivity on Muscle

I. Muscles and Gravity

II. Functional Anatomy

III. Biochemistry of Muscle Contraction

IV. Neural Control

V. Effects of Exercise on Muscles

VI. Disuse Atrophy of Muscle

VII. Effects of Inactivity

VIII. Spaceflight Findings

IX. Management of Disuse Atrophy

X. Diseases of Muscle Inactivity

XI. Conclusions

References

5 Metabolic and Endocrine Changes

I. Metabolic Changes with Inactivity

II. Post-Bed-Rest Orthostatic Hypotension and Countermeasures

III. Drug Metabolism and Drug Action

IV.Conclusions

References

6 Psychosocial and Chronophysiological Effects of Inactivity and Immobilization

I. Introduction

II. Isolation

III. Immobilization

IV. Summary and Conclusions

References

7 Exercise Responses after Inactivity

I. Introduction

II. Exercise Performance after Bed Rest

III. Physiologic Changes Associated with Reduced Work Capacity

IV. Environmental Factors Affecting Exercise Performance after Bed Rest

V. Recovery from Bed Rest Inactivity

VI. Practical Applications

VII. Summary

References

8 Conclusions

I. Cardiovascular Effects

II. Effects on Bone

III. Effects on Muscle

IV. Metabolic and Endocrine Changes

V. Psychosocial Aspects of Immobilization

VI. The Impact of Exercise

VII. Summary

References

Index