1. Environmental Fitness for Military Personnel
Defining Total Fitness for the 21st Century , Bethesda MD, 6-9 Dec 2009
Environmental Fitness for Military Personnel
Michael N. Sawka, Ph.D.
U.S. Army Research Institute of Environmental Medicine
DISCLAIMER: The views expressed in this presentation (slides, etc.) are those of the author and do not reflect the official policy of the Department of the Army, Department of Defense, or the U.S. Government.

2. Workshop Definitions
Fitness: “Ability of our Warriors to Perform their duties well, withstand the multiple stressors of deployment and war, and recovery rapidly after stress and injury”
Resiliency: “Ability to adapt to new stressful situations, new challenges, solve difficulty problems”

3. Fact: Wars are Fought Outdoors with Extended
Exposure to Harsh Conditions & Exhaustive Work

4. WARRIOR STRESS / STRAIN FACTORS
(Physical Domains)
Temperature
Humidity
Wind
Altitude
Environment
Mission
Biomedical
Age
Anthropometry
Gender
Health
Nutrition
Sleep Status
Acclimation / AT
Physical Fitness Fitness
Emotions - Motivation
Hydration
Pharmaceuticals X
Metabolic Rate
Duration
Type of Work
Clothing / Equipment
Heat stress assessment needs to account for climate, demands of event and status of athlete.

5. Altitude Impacts on Afghanistan Operations
15,620 ft Tora Bora
Pharmaceuticals to reduce Acute Mountain Sickness (AMS) degrade performance & adverse side effects
13,000 ft Operation Snipe
Above 10,000 ft, entire force has disrupted sleep contributing to fatigue & impaired judgment
10,470 ft Takur Ghar
“Aborted Missions from Altitude Sickness” – 24th STS, JSOC
8,400 ft Korengal Valley
Above 8,000 ft,
altitude sickness incidence ranges from 20-80%
“Operation Anaconda, hospitalizations for severe AMS” – Army Times
8,200 ft Operation Mountain Storm
“Combat Ineffective”, “Cannot Pursue Enemy” – PM, Marine Expeditionary Rifle Squad
Above 6,000 ft, entire force has degraded physical performance (40% reduction at 10,000 ft)
“Soldier’s total load was around 65 to 80 pounds, but at 8,000 – 10,000 ft of altitude the weight felt more like 120 pounds after 5 minutes of movement”
- Center for Army Lessons Learned
“The physical demands that mountain operations place on our Soldiers cannot be overstated”…“Soldier’s load becomes critical”…“and takes on a whole new meaning in the thin air of mountain ridges”
– MG W. Wojdakowski, Commandant Infantry Center & School

6. Consequences of Poor Environmental Fitness
Mission Degradation
Reduced physical and cognitive performance
Environmental Injuries (e.g., heat stroke, frostbite, altitude sickness)
Increased injury susceptibility (accidents, CNS, organ)
Increased Logistical Burden
Medical / Evacuation
Manpower
Increased Health Care Costs
Disability (e.g., frostbite)
Mortality (heat stroke induced heart, GI, liver diseases)

7. Physical Fitness = Environmental Fitness/
High Aerobic Fitness Greater Performance Decrement with Altitude Exposure
In mountains, human’s are fighting platform
(3.28 ft = 1 meter)
Fulco et.al. Aviat. Space Env. Med. 1998

8. Components of Environmental Fitness
Environmental Fitness (altitude, heat, cold, hyperbaric)
Acclimation
(stress specific)
Acquired Tolerance
Acquired
Cross- Tolerance
(non-stress specific)
Acquired Cross Tolerance – “Induce adaptation to a stressor without prior exposure” - M. Horowitz
Acquired Tolerance –
“Cellular / tissue protection against a given amount or greater physiologic strain”
Acclimation: -
“Reduced physiologic strain & sustained performance after repeated days of exposure”

9. Examples of Acclimation & Acquired Tolerance
Heat Acclimation
(reduced strain)
Acquired Thermal Tolerance (Reduced morbidity & mortality at given strain)
(rats exposed to
heat strain)
Cohen & Gisolfi MSSE 1982
Fruth & Gisolfi JAP 1983

10. Acquired Cross Tolerance
Robust Stress Pathways
Heat
Hypoxia
Physical Exercise
Protective Outcomes
Environmental Injuries
Muscle Injury
Neural Injury
Surgical Survival
Trauma Recovery

11. Examples of Acquired Cross Tolerance
from Prior Heat (HA) or Prior Hypoxia (PH)
HA improves BBB integrity following closed head injury (Shohami et al. Acta Neurochir Suppl 1994)
HA increases time to hyperbaric-induced CNS oxygen toxicity (Arieli et al. Brain Res. 2003)
HA reduces myocardial damage following ischemia (Maloyan et al. Physiol. Genomics 2005)
Heat acclimation improves cognitive performance after closed head injury (Shein et al. J Cereb Blood Flow Metab 2005)
HA reduces skeletal muscle damage from eccentric exercise (Nosaka et.al. Eur. J. Appl. Physiol. 2007)
HA during reloading of immobilized skeletal muscle reduces damage & improves re-growth (Selsby et.al. J Appl. Physiol. 2007)
PH protects from depression following psychoemotional stress (Rybnikova et al. Neurosci Behav Physiol, 2008)
PH protects against passive avoidance learning deficits (Rybnikova et al. Behav Brain Res, 2005)
PH protects cognitive ability during stress (Shao et al Neurosignals, 2007)
PH protects myocardium against ischemic injury (Murry et al. Circulation 1986)
PH protects the myocardium against ischemia-reperfusion injury. (Lin et al. J Physiol, 2008)

12. Poor Environmental Fitness Compromises Resiliency to Other Stressors
(“Multiple Hit Hypothesis”)
Example Hyperthermia:
Reduces Brain Blood Flow
Blood Brain Barrier Breakdown
Exacerbates Drug-Induced Toxicity
Exacerbates Nanoparticle Induced Toxicity
Increases Chemical Toxicity
Exacerbates CNS Injury from Occlusion

13. Standards for Environmental Fitness
“Altitude Acclimatization & Illness Management” (TB MED 505), 2010 (NATO AMedP-14 Vol.3)
“Prevention & Management of Cold-Weather Injuries” (TB MED 508), (Allied Medical Publication (NATO AMedP-14 Vol.2)
“Heat Stress Control & Heat Casualty Management” (TB MED 507/AFPAM ), (Allied Medical Publication (NATO AMedP-14 Vol.1
Associated Pamphlets & Posters

14. Metrics to Assess Environmental Fitness
Current:
Acclimatization: Functional Outcomes, Exposure Dosage (approximation)
Acquired Tolerance: None
Cross-Tolerance: None
Future:
Acclimatization: Dosage monitor & status algorithms (group, individual)
Acquired Tolerance: “omics” biomarkers
Cross-Tolerance: “omics” biomarkers

15. Example: Altitude Acclimatization Monitor
Simple measure of altitude exposure (barometric pressure and duration)
to predict altitude acclimatization status for target altitude
Inputs:
Barometric pressure & time (auto)
Target Altitude (user entry)
Output:
Acclimatization Status
AMS Risk
AMS Severity
4500 m
(lines below at
500 m increments
Altitude Dosage Profile
Altitude Sickness Model

16. Summary: Environmental Fitness
Essential to perform duties well in harsh environments
Different from Physical Fitness
Specific to environment
Acclimation (specific)
Acquired Tolerance (specific)
Acquired Cross Tolerance (broad; key to induce resiliency?)
Poor fitness, increase vulnerabilities (multiple hit hypothesis)
Metrics: currently general; altitude dosage & status monitor