Page 162 - Biobehavioral Resilence to Stress

Resilience and

Survival in Extreme 7

Environments

KARL E. FRIEDL

U.S. Army Research Institute of Environmental Medicine

DAVID M. PENETAR
McLean Hospital/Harvard Medical School

Contents
Introduction ........................................................................................................ 139
Extremes of Human Endurance ...................................................................... 140
The Physiological Basis of Performance Limits and Injury ......................... 144

High Altitude ................................................................................................. 144
High Work Intensity and Energy Balance ................................................. 148
Th ermal Strain ............................................................................................... 149
Sleep and Fatigue ........................................................................................... 152
Psychological Stress ....................................................................................... 155
Physiological Limits to Risky Behavior........................................................... 156

Psychosocial Modifiers of Environmental Stress and Health ...................... 158

Resilience Modifiers: Exercise and Other Interventions .............................. 162
Conclusions and Recommendations for Future Research ........................... 165
Summary ............................................................................................................. 166
References ............................................................................................................ 166

In appreciation for whatever it is that makes men accomplish the impossible.
—Alfred Lansing, Endurance, Shackleton’s Incredible Voyage, 1959

Introduction

Human physical survival under harsh environmental conditions is fairly well
understood and somewhat predictable as a function of known physiological

mechanisms. These essential mechanisms can be seen as analogous to the
factors that support or limit machine performance (e.g., fuel levels—energy
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