1. Exercise: The Environment and Special Populations
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2. Learning Objectives Describe how to prevent heat loss during exercise
List several important guidelines for exercising in a hot environment
Describe the appropriate clothing for exercising in the heat
Differentiate among the various types of heat injury
Discuss how heat acclimatization reduces the risk of heat injury
Describe the appropriate clothing for exercising in a cold environment
List two major forms of air pollution that affect exercise performance
Describe exercise strategies for coping with air pollution
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3. Learning Objectives (cont.)
Discuss the importance of the following factors in achieving lifetime physical fitness: goal setting, selection of physical activities, planning exercise sessions, monitoring fitness programs, and social support
Outline several common misconceptions about physical fitness
List age-related changes in fitness and wellness and describe actions that you can take to maintain fitness and wellness throughout the life span
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4. Environmental Effects on Human Performance
Body temperature is regulated to stay close to a set point (98.6°F or 37°C)
Changes can result in serious bodily injury
Altitude and air pollution reduce the amount of oxygen that gets into the blood, meaning the body works harder
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5. Temperature Ranges for Human Survival
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6. Exercising in the Heat
Exercise muscle contraction = increase in body heat
Hot/humid conditions = excess body heat
Heat injury occurs if body temp exceeds 105 degrees
Heat illness = dizziness, nausea, lack of sweat, and dry, hot, or clammy skin
Short-term exposure (30–60 min) can cause heat injury
There are two primary means of heat loss/cooling during exercise
Convection: movement of air or water around the body
The faster the air or water flow, the greater the heat loss
Evaporation: heat release as sweat converts to gas
If air temperature and humidity are high, evaporation is limited
Determining factor: air temperature and humidity
Evaporation = most important means of body heat loss
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7. Heat Index
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8. Clothing for Hot Weather
Minimize the amount you wear
Maximize exposed surface area for evaporation
Clothes should be lightweight, light colored, absorb moisture, and allow air to move freely
Avoid heavyweight, rubber/plastic materials
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9. Heat Acclimitization
Acclimitization = Physiological adaptations to environment
Within 10–12 days of regular exercise during heat exposure
Sweating begins earlier
More sweat is produced (aiding evaporation)
Blood volume increases
Exercise heart rate decreases
Body temperature decreases
Heat injury = heat load exceeds body's ability to regulate body temperature, resulting in
Heat cramps
Heat exhaustion
Heat stroke
To determine body's heat load, monitor heart rate
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10. Temperature Changes on Heart Rate
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11. Exercising in Hot/Humid Conditions
Begin exercising slowly, keep sessions short (15–20 minutes max)
Monitor heart rate often, keep intensity low
Wear appropriate clothing
Stay hydrated! Drink fluids before, during, after exercise sessions
Exercise in the morning or evening, when temperatures are cooler
If you must exercise mid-day, stay in the shade
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12. Exercising in the Cold
Air temperature below 60°F requires warm clothing to prevent excessive loss of body heat
Long periods of exposure overwhelm body's ability to maintain temperature level
Losing body heat = hypothermia, disorientation, and may be life threatening
Avoiding Hypothermia
Limit duration of exercise
Don't get wet
Dress in layers with appropriate amounts and types of clothing
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13. Clothing for Cold Weather
Proper Clothing, Worn in Layers
Should trap enough heat to maintain body temperature, without overheating
Layering especially important for upper body
Base Layer
Removes moisture from skin, moves it to next layer (wicking)
Avoid cotton, tends to stay wet
Middle Layer
Further insulates the body, wicks moisture outward
Often heavier than base layer
Outer Layer
Protects you from wind/water
Windproof, waterproof, ventilated, lightweight jacket
Hats, scarves, gloves protect extremities from frostbite
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14. Layering Clothing in Cold Environments
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15. Exercising at High Altitudes
A lower barometric pressure = less oxygen transported in blood, decreasing VO2max, and exercise tolerance
Acute Mountain Sickness (AMS)
Occurs at altitudes above 8000 ft
Affects approx. 20% of individuals exercising at or above this altitude
Affects some (up to 80%) who fly into high-elevation areas
Symptoms: severe headaches, nausea, weakness, and dizziness
Avoiding AMS
Ascend slowly
Sleep at lowest elevation possible
If hiking or driving up, don't go farther if you feel AMS effects
Drink plenty of water
Avoid tobacco, alcohol, depressants
Eat a high-carbohydrate diet
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16. Effects of Elevation on Heart Rate and Ventilation
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17. Exercise and Air Pollution
Major Forms of Air Pollution
Ozone (gas produced from sunlight and car exhaust)
Extremely irritating to lungs and airways
Causes chest tightness, coughing, headaches, nausea, throat and eye irritation, and bronchoconstriction
May trigger asthma attacks
Carbon monoxide (gas from fossil fuels and cigarette smoke)
Reduces blood's capacity to carry oxygen to body and muscles
High-traffic environments = serious health threat
Coping with air pollution
Avoid exercise when/where
levels of pollutants are highest
automobile traffic is heavy
Complete Lab 12.1: Exercising in Harsh Environments
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18. Avoiding High-Pollution Exercise Times
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19. Lifelong Exercise Considerations
Maintaining healthy level of fitness/wellness
Lifelong process
Your actions now significantly impact future health
Fitness cannot be stored
Principle of reversibility
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20. Exercise Programming During All Life Stages
Most adults' physical activity declines with age and major lifestyle changes
Maintain regular exercise as you age
Properly plan exercise sessions, adjust schedule as your lifestyle changes
Join a health club
Get support or hire help if needed
Change your physical activity needs as you age
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21. Summary
Evaporation is the most important means of heat loss during exercise in a hot environment. Maximize the body surface area exposed to the air to ensure adequate release of body heat through evaporation
Heat acclimatization occurs after several days of exposure to a hot environment. During exercise in hot environments, drink plenty of fluids to avoid dehydration
Avoid hypothermia when exercising in a cold environment by dressing in layers, and in appropriate amounts and types of clothing
Exercise at high altitude reduces the amount of oxygen in the blood, which reduces oxygen transport to the working muscles and lowers both VO2max and exercise tolerance
Minimize the effects of air pollution during exercise by avoiding exercise when ozone or carbon monoxide levels are highest
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22. Summary (cont.)
Exercise must be performed regularly throughout life to achieve the benefits of physical fitness, wellness, and disease prevention
Appropriate exercise is safe and beneficial for healthy pregnant women
Older adults can safely participate in regular exercise to gain and maintain fitness and reduce risk of disease
Numerous changes take place in the body and mind during the aging process
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