Integrative Strategies to Optimize Metabolic Performance in the Heat Karl E. Friedl, PhD, COL(Ret) U.S. Army Research Institute of Environmental Medicine Natick, Massachusetts 01760-5007
4th International Conference on Soldier Physical Performance Melbourne, Australia Unclassified
Heat Strain Decision Aid (HSDA)
Potter et al. J Therm Biol 2017;64:78-85 Karl E. Friedl, PhD/
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Heat Strain Decision Aid (HSDA)
Should we consider body morphology when assigning personnel to thermally challenging duties? Nigel Taylor, 2017
Can we model aerobic fitness as a separate factor and distinguish high motivation (risk) from more effective cardiovascular response ?
Karl E. Friedl, PhD/
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Voluntary dehydration and water taste perceptions
Szlyk et al. Physiol Behav 1989;49:639-47 Karl E. Friedl, PhD/
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Taste perception of water
Can we make warm water more palatable?
Karl E. Friedl, PhD/
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Nutrition in the tropics
Have we resolved the 1899 debate about hot weather rations?
Karl E. Friedl, PhD/
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Brown adipose tissue
Yet to be seen: Implications to resting metabolic rate, thermogenesis and weight regulation Karl E. Friedl, PhD/
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Capsaicin feeding in humans
WEM 2000;11:152-6 Karl E. Friedl, PhD/
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Metabolic control interactions Ground squirrels and camels better tolerate high temperatures (>40 C), in part through decreased sensitivity of TRPV1 (transient receptor potential vanilloid 1) without changing response to capsaicin
Laursen et al. PNAS 2016;113:11342-7 Karl E. Friedl, PhD/
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Sleep in the heat 26 C, 50% RH 32 C, 80% RH
Okamoto-Mizuno et al. Physiol Behav 2005;83:759-65 Karl E. Friedl, PhD/
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If you stay warm, you can’t sleep!
Based on: Scholander et al. JAP 1958;13:211-218 Karl E. Friedl, PhD/
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Meditation and thermogenesis
Benson et al., Nature 1982;295:234-5
Consistent increase in finger and toe temperatures observed in experience Tum-yo meditators Karl E. Friedl, PhD/
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Meditation and thermogenesis With advanced meditative practices, resting metabolism could be raised (up to 61%) and lowered (up to 64%), characterized by marked EEG beta activity
Benson et al., Behav Med 2010;16:90-5 Karl E. Friedl, PhD/
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Conclusions 1. aerobic fitness is a key modifiable factor that appears to significantly affect heat tolerance and performance in the heat needs to be quantitatively modeled 2. new taste perception biology related to sensations of coolness builds on previous Army investigations to improve drinking 3. fat macronutrient metabolism in the tropics has been a recurring research theme and can be resolved with modern metabolic methods, and underfeeding effects constitute related hypotheses 4. capsinoids increase non-thermal sweating but human studies have not carefully controlled for important moderating factors observed in animal studies or considered new insights to BAT regulation; 5. temperature moderates the quality of sleep but earlier studies on sleep architecture can now be extended outside of the laboratory to devise strategies to optimize restorative sleep in the heat; and 6. neurological control of metabolic rate and body heat production has been demonstrated by specially trained individuals and can be generalized with assistive technologies/real time biofeedback Karl E. Friedl, PhD/
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What’s old is new again when reexamined with new methods and technologies
Karl E. Friedl, PhD/
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