Chapter 6: Environmental Conditions

Chapter 6: Environmental Conditions

Environmental stress can adversely impact an athlete’s performance and pose serious health threats • Areas of concern • Hyperthermia • Hypothermia • Altitude • Exposure to the sun • Lightening storms • Air pollution • Circadian dysrhythmia

Hyperthermia • Athletic trainers require knowledge and information concerning temperature, humidity and weather to adequately make decisions regarding environmental dangers • Has caused a number of deaths over the years • Must manage heat stress appropriately

Heat Stress • Extreme caution should be used when training in the heat (overexposure could result in heat illness) • It is preventable • Athletes that train under these extreme conditions are at risk • Physiologically the body will continue to function if body temperature is maintained • Body must be dissipate heat to maintain homeostasis

Metabolic Heat Production • Normal metabolic function results in production of heat (will increase with intensity of exercise) • Conductive Heat Exchange • Physical contact with objects resulting in heat loss or gain • Convective Heat Exchange • Body heat can be lost or gained depending on circulation of medium • Radiant Heat Exchange • Comes from sunshine and will cause increase in temperature

Evaporative Heat Loss • Sweat glands allow water transport to surface • Evaporation of water takes heat with it • When radiant heat and environment temperature are higher than body temperature, loss of heat through evaporation is key • Lose 1 quart of water per hour for up to 2 hours • Air must be relative water free for evaporation to occur • relative humidity of 65% impairs evaporation • relative humidity of 75% stops evaporation

Monitoring Heat Index • Heat, sunshine and humidity must be monitored closely • Wet bulb globe temperature index (WBGT) provides objective measure for determining precautions concerning participation in hot • WGBT incorporates different thermometer readings • Dry bulb (standard mercury temperature) • Wet bulb (thermometer with wet gauze that is swung around in air) • Black bulb (black casing that measures radiant heat) • Formula yields WBGT index

DBT and WBT can be measured with psychrometer (combines both thermometers) • Wet bulb will be lower due to evaporation of water • Drier air = greater depression of wet bulb temperature due to evaporation • Ventilation is provided by whirling thermometer (sling psychrometer) or suction fan (aspiration psychrometer) • Newer models utilize digital sensors

Heat Illnesses • Heat rash (prickly heat) • Benign condition associated with red, raised rash, combined with prickling with sweat • Result of continuously wet un-evaporated sweat • Continually toweling the body will prevent • Generally localized to areas covered with clothing

Heat Syncope (heat collapse) • Associated with rapid fatigue and overexposure, standing in heat for long periods of time • Caused by peripheral vasodilation, or pooling of blood in extremities resulting in dizziness and fainting • Treat by placing athlete in cool environment, consuming fluids and laying down • Heat Cramps • Painful muscle spasms (calf, abdominal) due to excessive water loss and electrolyte imbalance • Occurs in individual in good shape that overexert themselves

Prevent by consuming extra fluids and maintaining electrolyte balance • Treat with fluid ingestion, light stretching with ice massage • Return to play unlikely due to continued cramping

Exertional Heat Exhaustion • Result of inadequate fluid replacement • Unable to sustain adequate cardiac output • Will exhibit signs of profuse sweating, pale skin, mildly elevated temperature, dizziness, nausea, vomiting or diarrhea, hyperventilation, persistent muscle cramps, and loss of coordination • May develop heat cramps or become faint/dizzy • Core temperature will be <104o • Performance may decrease

Immediate treatment includes fluid ingestion (intravenous replacement, ultimately), place in cool environment, remove excess clothing • Must continue to monitor vital signs • Return to play – must be fully hydrated and be cleared by a physician

Exertional Heatstroke • Serious life-threatening condition, with unknown specific cause • Characterized by sudden onset - sudden collapse, LOC, CNS dysfunction, flushed hot skin, minimal sweating, shallow breathing, strong rapid pulse, and core temperature of > 104o F • Breakdown of thermoregulatory mechanism

Drastic measures must be taken to cool athlete • Strip clothing • Sponge with cool water • Do not immerse in water • Transport to hospital immediately • Cool first, transport second • Athlete should avoid exercise for a minimum of one week and gradually return to full practice • Must be asymptomatic and cleared by physician

Malignant hyperthermia • muscle disorder causing hypersensitivity to anesthesia and heat • Similar S&S to heatstroke - muscle biopsy is needed to detect • Athlete will complain of muscle pain after exercise • Temperature will remain elevated 10-15 minutes following exercise • Athlete with condition should be disqualified from competition in hot, humid environments

Acute Exertional Rhabdomyolysis • Sudden catabolic destruction and degeneration of skeletal muscle (myoglobin and enzyme leakage into vascular system) • Occurs during intense exercise in heat and humidity resulting in: • gradual muscle weakness, swelling, pain, dark urine, renal dysfunction • severe case = sudden collapse, renal failure and death • Associated with individuals that have sickle cell trait • Should be referred to a physician immediately

Exertional Hyponatremia • Fluid/electrolyte disorder resulting in abnormally low concentration of sodium in blood • Caused by ingesting too much fluid before, during and after exercise • May be result of too little sodium in diet or in ingested fluids over a period of prolonged exercise • Athletes that ingest large quantities of water and sweat over several hours are at risk (marathon, triathlon) • Preventable – must maintain balance

Signs and Symptoms • Progressively worsening headache, nausea, vomiting • Swelling of hands and feet, lethargy, apathy or agitation • Low blood sodium • Could compromise CNS and create a life-threatening situation • If levels can not be determined on-site, measures to rehydrate should be delayed and the athlete should be transported to a medical facility • Delivery of sodium, diuretics, or intravenous solutions may be necessary

Preventing Heat Illness • Common sense and precaution • Consume fluids and stay cool • Fluid and Electrolyte Replacement • Body requires 2.5L of water daily when engaged in minimal activity • 1-2% drop in body weight (due to dehydration) results in thirst • If thirst is ignored, dehydration results in: • nausea, vomiting, fainting and increased risk for heat illness

More likely to occur when exercising outdoors sweating heavily and engaging in strenuous exercise • Prevent through hydration, don’t ignore thirst, and don’t rely on it being your indicator • Generally only 50% of fluid is ever replaced and should therefore be replaced before, during and after exercise • Athletes should have unlimited access to water to prevent decrements in performance and hypohydration

Using Sports Drinks • More effective than just replacing fluids with water • Flavoring results in increased desire to consume • Replaces fluids and electrolytes • Water alone can prematurely stop thirst response and initiate fluid removal by kidneys • Small amounts of sodium help in retention of water • Different drinks have different nutrient levels • Optimal CHO level is 14g per 8 ounces of water • More CHO results in slower absorption • Effective for both short term and endurance activities

Gradual Acclimatization • Most effective method of avoiding heat stress • Involves becoming accustomed to heat and exercising in heat • Early pre-season training and graded intensity changes are recommended with progressive exposure over 7-10 day period • 80% of acclimatization can be achieved during first 5-6 days with 2 hour morning and afternoon practice sessions

Identifying Susceptible Individuals • Athletes with large muscle mass • Overweight athletes (due to increased metabolic rate) • Death from heat stroke increase 4:1 as body weight increases • Women are physiologically more efficient with regard body temp. regulation • Others that are susceptible include, those with poor fitness, history of heat illness, or febrile condition

Uniform Selection • Base on temperature and humidity • Dress for the weather and temperature • Avoid rubberized suits • Weight Records • Keep track of before and after measures for first two weeks • If increase in temperature and humidity occurs during the season, weights should again be recorded • A 3-5% loss of BW will reduce blood volume and could be a health threat

Temperature and Humidity Reading • Dry and wet bulb readings should be taken on the field prior to practice to monitor heat index • Modify practice according to severity of environmental conditions

Guidelines for Athletes Who Intentionally Lose Weight • Predispose themselves to heat related injuries and could create life-threatening situations • Weight loss should not be accomplished through dehydration • Gradual process over weeks and months and should be a result of body fat lost • NCAA and high school federations have established guidelines for weight loss in wrestling

Hypothermia • Cold weather vs. nature of particular sport • Most activity allows for adequate heat production (increased metabolism) and dissipation, allowing for sufficient functioning • Impact on warm-up and “down time” • Temperature in conjunction with wind chill and dampness or wetness can increase chances of hypothermia

65% of body heat is lost through radiation (head and neck 50%) • 20% through evaporation • 2/3 through skin and 1/3 through respiration • Problems arise when heat lost exceeds heat production via metabolism • Results in impairment of neuromuscular function • Drop in core stimulates shivering but stops after temp. drops below 85-90oF • Death is imminent when temp falls below 77-85oF.

Prevention • Apparel geared for weather to provide semitropical microclimate for body and prevent chilling • Waterproof and windproof fabrics that allow passage of heat and sweat and allow movement • Layers and adjusting them are key to maintaining body temperature (during period of (in)activity) • Inadequate clothing, improper warm-up and chill factor can lead to injury, frostbite, chilblains, and/or minor respiratory problems • Be aware of hydration levels as well to enhance blood volume and heat maintenance

Common Cold Injuries • Localized cooling can result in tissue damage • Formation of ice crystals between cells, destroys cells, disrupts blood flow, clotting may occur • Frost nip • Involves, ears, nose, chin, fingers, and toes • Occurs with high wind and/or severe cold • Skin appears firm with cold painless areas that may peel and blister (24-72 hours) • Treat with firm pressure, blowing warm air or hands in armpits (if fingers involved) • Do not rub

Frostbite • Chilblains result from prolonged exposure causing redness and swelling, tingling pain in toes and fingers • Due to poor peripheral circulation • Superficial Frostbite involves only skin and subcutaneous tissue • Appears pale, hard, cold and waxy • When re-warming the area will feel numb, then sting and burn • It may blister and be painful for several weeks • Deep Frostbite indicates frozen skin requiring hospitalization • Rapid re-warming is necessary (100-110oF) • Tissue will become blotchy red, swollen, painful and may become gangrenous

Altitude • Most events do not occur at extreme heights • As height increases, maximum oxygen uptake decreases resulting in a decrease in performance • Body compensates through tachycardia and hyperventilation • Responses are a result of having fewer red blood cells than necessary to adequately capture available oxygen

Adaptations • Increased height = reduced barometric pressure resulting in decreased partial pressure of oxygen = less saturation of red blood cells • Individual adaptations dependent on whether an the person is a native, resident or visitor • Native has larger chest capacity, more alveoli, capillaries and red blood cells • Resident makes partial adaptations (increased mitochondria and hemoglobin, glycogen conservation) • Visitor responds with increased breathing heart action, hemoglobin, blood alkalinity, myoglobin and changes in blood flow and enzyme activity

Other uncertainties with regards to training and competition • Time to adjust (2-3 weeks vs. 3 days) • Short adjustment allows acid-base balance to recover but does not allow significant changes in blood volume and maximum cardiac output • Altitude Illnesses • Acute Mountain Sickness • 1 out of 3 will experience when making the jump 7000-8000 feet. • Experience headache, nausea, vomiting, sleep disturbance, and dypsnea • Caused by brain disruption associated with sodium potassium imbalance resulting in fluid retention and cellular pressure changes

Pulmonary Edema • Occurs at 9000-10,000 feet. • Lungs accumulate fluid in alveolar walls forming pulmonary edema • Signs and symptoms: dypsnea, cough, headache, weakness and occasionally unconsciousness. • Treat by moving athlete to lower altitude and providing oxygen • Sickle Cell Trait • 8-10% of African Americans have sickle cell trait • In most the trait is benign • Abnormality in red blood cell hemoglobin structure • When hemoglobin is deoxygenated, cells clump together causing blood cell to develop sickle shape making it easy to destroy • Causes enlarged spleen and could rupture at high altitudes

Overexposure to Sun • Precautions must be taken to protect athletes, coaches, athletic trainers and support staff • Long Term Effects on Skin • Premature aging and skin cancer due to ultraviolet exposure • Premature aging is characterized by dryness, cracking and inelasticity of the skin • Skin cancer is the most common malignant tumor found in humans

Damage to DNA is suspected as the cause of cancer • Major types include basal cell carcinoma, squamous cell carcinoma and malignant melanoma • Rate of cure is 95% with early detection • Fair skinned individuals are more susceptible to these maladies

Using Sunscreen • Can help prevent damaging effects of UV radiation • Sunscreen effectiveness is expressed as SPF (sun protection factor) • Indicates how many times longer an individual can be exposed to the sun with vs. without sunscreen before skin turns red. • Greater the susceptibility the higher the SPF should be used • Should be worn by athletes, coaches and athletic trainers who are outside a considerable amount, and/or have fair complexion, light hair, blue eyes or skin that burns easily

Individuals with dark complexion should also apply • 60-80% of sun exposure occurs before the age of 20 • Sunscreen use is at its highest March - November but should be used year round (particularly between the hours of 10am-4pm) • It should be applied 15-30 minutes before exposure and re-applied after exposure to water, excess sweating, rubbing skin with clothing or a towel

Lightening Safety • #2 cause of death by weather phenomena • NATA has established position statement due to number of athletes and coaches potentially exposed to lightening scenarios • Emergency action plans must be set for this type of event • Involving chain of command, monitoring of weather service, decision making regarding removal and return to field

In the event of a storm, shelter indoors should be obtained • Other guidelines • Avoid large trees, flag/light poles, standing water, telephones, pools, showers, and metal objects (bleachers, equipment,umbrellas) • Last resorts find car, ravine, ditch or valley for safety • If hair stands up on hand you are in imminent danger and should get down on the ground but not flat as that increases surface area

Additional Guidelines • Lightening is generally accompanied by thunder (except 20-40% of the time due to atmospheric disturbances) • Flash-to-bang methods estimates distance away for the storm • From time lightening is sighted to the clap of thunder count, divide by 5 to calculate the number of mile away • Count of 30 indicates inherent danger • Count of 15 seconds everyone should leave the field

NATA and National Weather Service recommend returning to the field 30 minutes following the last clap of thunder or lightening strike • Major misconception is that lightening that is seen striking is coming down • In actuality it is the return stroke of the lightening going back up after it has already hit the ground

Lightening detector • Hand-held instrument • Able to detect storm occurring within 40 miles • Allows you to know level of activity and direction • When it detects a lightening stroke it emits an audible warning tone • Inexpensive alternative to setting up contract with weather service

Air Pollution • Major problem in urban areas, particularly when considering large periods of exposure • Two types • Photochemical haze: nitrogen dioxide and stagnant air acted on by sunlight to produce ozone • Smog: combination of carbon monoxide and sulfur dioxide

Ozone • 3 atom molecule of oxygen • reaction of oxygen, nitrogen oxides, hydrocarbons and sunlight • Minimum activity levels - ozone will not impact • Higher intensity will have a negative effect on work output • May experience shortness of breath, coughing, chest tightness, pain with deep breathing, nausea, eye irritation, fatigue, lung irritation, lowered resistance to lung infection • Asthmatics are at greater risk • May become desensitized over time

Chapter 6: Environmental Conditions