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.

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”

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

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.

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

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)

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

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”

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

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

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)

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

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), 2005. (Allied Medical Publication (NATO AMedP-14 Vol.2) “Heat Stress Control & Heat Casualty Management” (TB MED 507/AFPAM 48-152), 2003. (Allied Medical Publication (NATO AMedP-14 Vol.1 Associated Pamphlets & Posters

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

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

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