Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations

TABLE 6-5 Mean Oxygen Uptake during Rest, Moderate Activity, and Heavy Activity by Young Men (n = 7) in a Room Maintained at Different Temperatures

	Mean Oxygen Uptake (ml per minute)
Intensity of Activity	21.1°C (70°F)	29.4°C (85°F)	37.7°C (100°F)	Percent
Rest	273	282	304*	11.4
Moderate^†	521	525	590*	13.3
Heavy^‡	1422	1404	1570*	11.7
* p ≤ 0.05, i.e., effect of 100°F > 85°F or 70°F. ^† Fifty minutes on cycle ergometer. ^‡ Fifty minutes on cycle ergometer at 120 watts. SOURCE: Adapted from Consolazio et al. (1963).

study by Welch et al. were nonsignificant, there appeared to be a trend for a higher energy expenditure during walking in a hot desert environment when expressed either as kcal per hour or kcal per kg per hour, where kg represents total weight transported. However, more recent studies have failed to find significant differences (Klausen et al., 1967; Rowell et al., 1969; Sen Gupta et al., 1977; Shvartz et al., 1977; Young et al., 1985).

Shvartz et al. (1977) clearly indicated little difference in metabolic rate with ergometer exercise prior to heat acclimation (see Table 6-8). Sen Gupta et al. (1977) raised the possibility that although total energy expenditure during submaximal exercise was not different when the exercise was

TABLE 6-6 Oxygen Uptake by Young Men (n = 7) Performing Different Types of Exercise* in a Desert Environment, Yuma, Arizona

	Oxygen Uptake (ml per minute)
Exercise Type	Sun (37.8°C)	Shade (37.8°C)	Indoors (26°C)
Bicycle 1	754^†	683^†	641
Bicycle 2	813^†	751^†	681
Treadmill	1156	1197^†	1110
Resting	340^†	322	314
* Two separate cycle ergometer rides that are indicated here as bicycle 1 and 2. ^†p < 0.05. SOURCE: Adapted from Consolazio et al. (1970).

Table of Contents

Front Matter R1-R14

Part I: Committee Summary and Recommendations 1-2

1. Introduction and Backgrounds 3-44

2. Conclusions and Recommendations 45-52

Part II: Invited Presentations 53-54

3. Physiological Responses to Excercise in Heat 55-74

4. Effects of Excercise and Heat on Gastrointestinal Function 75-86

5. Water Requirements During Excercise in the Heat 87-96

6. Energetics and Climate with Emphasis on Heat: A Historical Perspective 97-116

7. The Effect of Excercise and Heat on Mineral Metabolism and Requirements 117-136

8. The Effect of Excercise and Heat on Vitamin Requirements 137-172

9. Heat as a Factor in the Perception of Taste, Smell, and Oral Sensation 173-186

10. Effects of Heat on Appetite 187-214

11. Situational Influences on Food Intake 215-244

Part III: U.S. Army Presentations: A Reevaluation of Sodium Requirements for Work in the Heat 245-246

12. Responses of Soldiers to 4-gram and 8-gram NaCl Diets During 10 Days of Heat Acclimation 247-258

13. Endocrinological Responses to Dietary Salt Restriction During Heat Acclimation 259-276

14. Subjective Reports of Heat Illness 277-294

Part IV: Committee Discussion Paper 295-296

15. Food Intake, Appetite, and Work in Hot Environments 297-304

Appendixes 305-306

Appendix A: Military Recommended Dietary Allowances, AR 25-40; 1985 307-328

Appendix B: Nutritional Needs in Hot Environments -- A Selected Bibliography 329-352

Appendix C: Biographical Sketches 353-362

Index 363-378