This volume examines the current state of knowledge concerning the influence of a hot environment on nutrient requirements of military personnel. A parallel concern is ensuring that performance does not decline as a result of inadequate nutrition.

The committee provides a thorough review of the literature in this area and interprets the diverse data in terms of military applications. In addition to a focus on specific nutrient needs in hot climates, the committee considers factors that might change food intake patterns and therefore overall calories. Although concern for adequate nutrition for U.S. soldiers in Saudi Arabia prompted the initiation of this project, its scope includes the nutrient needs of individuals who may be actively working in both hot-dry and hot-moist climates.

Contents

• COMMITTEE ON MILITARY NUTRITION RESEARCH
• FOOD AND NUTRITION BOARD
• PREFACE
• PART I. COMMITTEE SUMMARY AND RECOMMENDATIONS
  • Overview
  • 1. Introduction and Background
    • The Committee's Task
    • Military Recommended Dietary Allowances
    • Physiological Changes Arising from Exercise and Heat
    • Changes in Nutrient Requirements for Hot Environments
    • Factors that may Influence Eating Patterns, Food Preferences, and Food Intake in Hot Environments
    • Social and Psychological Influences on Food Intake During Military Operations
    • Conclusion
    • References
  • 2. Conclusions and Recommendations
    • Conclusions
    • Recommendations
    • Areas for Future Research
    • References
• PART II. INVITED PRESENTATIONS
  • Overview
  • 3. Physiological Responses to Exercise in the Heat
    • Introduction
    • Core Temperature Responses to Exercise
    • Metabolism
    • Skeletal Muscle Metabolism
    • Skin Blood Flow and Circulatory Responses
    • Summary
    • References
  • 4. Effects of Exercise and Heat on Gastrointestinal Function
    • Introduction
    • Gastrointestinal Symptoms
    • Importance of GI Manifestations with Exercise-Heat Stress
    • Gastric Emptying
    • Intestinal Absorption
    • Prevention and Management
    • References
    • Discussion
  • 5. Water Requirements During Exercise in the Heat
    • Introduction
    • Distribution of Body Water
    • Avenues of Fluid Loss and Gain
    • Determinants of Sweat Rate
    • Water Requirements
    • Conclusions and Recommendations
    • References
    • Discussion
  • 6. Energetics and Climate with Emphasis on Heat: A Historical Perspective
    • Introduction
    • Early Appraisals
    • Energy Expenditure: Submaximal Exercise
    • Acclimatization/Acclimation
    • Appetite
    • Resting Metabolism/Dietary-Induced Thermogenesis
    • Dietary Deficiencies
    • A Perspective
    • References
  • 7. The Effect of Exercise and Heat on Mineral Metabolism and Requirements
    • Introduction
    • Effects of Exercise and Heat on Iodine, Chromium, and Selenium Metabolism
    • Effects of Exercise and Heat on Iron Metabolism
    • Effects of Exercise and Heat on Zinc Metabolism
    • Influence of Exercise and Heat on Magnesium Metabolism
    • Effects of Exercise and Heat on Copper Metabolism
    • Conclusions
    • References
    • Discussion
  • 8. The Effect of Exercise and Heat on Vitamin Requirements
    • Introduction
    • Water-Soluble Vitamins
    • Fat-Soluble Vitamins
    • Conclusions and Recommendations
    • References
    • Discussion
  • 9. Heat as a Factor in the Perception of Taste, Smell, and Oral Sensation
    • Introduction
    • Sensory Effects of Temperature
    • Physiological and Psychological Effects of Temperature
    • Summary and Suggestions for Future Research
    • Acknowledgment
    • References
    • Discussion
  • 10. Effects of Heat on Appetite
    • Introduction
    • Environmental Temperature, Eating, and Thermoregulation
    • Effects of Eating on Thermoregulation
    • Effects of Heat on Appetite
    • Conclusions and Recommendations
    • References
    • Discussion
  • 11. Situational Influences on Food Intake
    • Introduction
    • The Underconsumption Problem
    • Problem Definition
    • Why is Ration intake Insufficient?
    • Laboratory and Field Differences
    • Situational Influences
    • Conclusions and Recommendations
    • References
    • Discussion
• PART III. U.S. ARMY PRESENTATIONS: A REEVALUATION OF SODIUM REQUIREMENTS FOR WORK IN THE HEAT
  • Overview
  • 12. Responses of Soldiers to 4-gram and 8-gram NaCl Diets During 10 Days of Heat Acclimation
    • Introduction
    • Methods
    • Results
    • Discussion
    • Conclusions
    • Acknowledgments
    • References
    • Discussion
  • 13. Endocrinological Responses to Dietary Salt Restriction During Heat Acclimation
    • Introduction
    • Methods
    • Results
    • Discussion
    • Conclusions and Recommendations
    • Acknowledgments
    • References
    • Discussion
  • 14. Subjective Reports of Heat Illness
    • Introduction
    • Method
    • Results
    • Discussion
    • Conclusions
    • References
    • Discussion
• PART IV. COMMITTEE DISCUSSION PAPER
  • Overview
  • 15. Food Intake, Appetite, and Work in Hot Environments
    • Introduction
    • Observational Data on Intake
    • Conclusions and Research Recommendations
    • References
• APPENDIXES
  • A Military Recommended Dietary Allowances, AR 25-40 (1985)
  • B Nutritional Needs in Hot Environments—A Selected Bibliography
  • C Biographical Sketches

This report was produced under grants DAMD17-86-G-6036/R and DAMD17-92-J-2003 between the National Academy of Sciences and the U.S. Army Medical Research and Development Command. The views, opinions, and/or findings contained in chapters in Parts II and III that are authored by U.S. Army personnel are those of the authors and should not be construed as official Department of the Army positions, policies, or decisions, unless so designated by other official documentation. Human subjects who participated in studies described in those chapters gave their free and informed voluntary consent. Investigators adhered to U.S. Army regulation 70-25 and United States Army Medical Research and Development Command regulation 70-25 on use of volunteers in research. Citations of commercial organizations and trade names in this report do not constitute an official Department of the Army endorsement or approval of the products or services of these organizations. The chapters are approved for public release; distribution is unlimited.

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance. Part I of this report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to enlist distinguished members of the appropriate professions in the examination of policy matters pertaining to the health of the public. In this, the Institute acts under both the Academy's 1863 congressional charter responsibility to be an adviser to the federal government and its own initiative in identifying issues of medical care, research, and education. Dr. Kenneth R. Shine is president of the Institute of Medicine.