Chapter 24
Exercise and the Environment

EXERCISE PHYSIOLOGY

Altitude

•Atmospheric pressure

–________________ at higher altitude

•Partial pressure

–Same percentages of O₂, CO₂, and N₂ in the air

–Lower partial pressure of _______, _______, and ________

–Hypoxia: ________ (altitude)

–Normoxia: normal PO₂ (_________)

–Hyperoxia: _____ PO₂

Effect of Altitude on Performance

•Short-term anaerobic performance

–Lower PO₂ at altitude should have ____ __________ of performance

–Lower air resistance may ________ performance

•Long-term aerobic performance

–Lower PO₂ results in poorer aerobic performance

Effect of Altitude on VO_2max

•__________ VO_2max at higher altitude

•Up to _____________ altitudes (~4,000m)

–Decreased VO_2max due to decreased arterial ________

At higher elevations

–Rate of VO_2max reduction also due to fall in maximum _________ _______

Changes in VO_2max with Increasing Altitude

Effect of Altitude on Submaximal Exercise

•Elicits ___________ heart rate

–Due to lower ________ content of _________ blood

•Requires higher _____________

–Due to reduction in number of O₂ molecules per liter of air

Effect of Altitude on Submaximal Heart Rate Response

Effect of Altitude on Submaximal Ventilation Response

Adaptation to High Altitude

•Production of more __________ ________ cells

–Counter desaturation caused by __________ PO₂

•In those who grew up at altitude

–Have complete __________ in arterial _____________ content and VO_2max

In those recently arriving at altitude

– Adaptations are _________ complete

Training for Competition at Altitude

•Effect of training at altitude on VO_2max __________ between athletes

–Due to degree of saturation of ___________

•Some athletes can improve __________ by training at altitude, others cannot

– May be due to _________ _________ before arriving at altitude

•Some athletes have higher _________ upon return to _________ altitude, while others do not

–Could be due to “_________” effect

•Cannot train as intensely at altitude

The Quest for Everest

•Mount Everest was climbed without oxygen in 1978

–Previously thought that VO_2max at summit would be just above rest

–Actually, VO_2max estimated at 15 ml•kg^-1•min^-1

•Due to miscalculation of barometric pressure at summit

Challenges of
High Altitude Climbing

•Successful climbers have great capacity for _________

–Drives down _________ and _________in blood

–Allows more _________ to bind with _________ at same PO₂

•Climbers must contend with loss of appetite

–Results in loss of _________

–Reduction in muscle fiber _________

Heat

–_________

–Elevated body temperature

•Heat-related problems

–Heat _________

–Heat _________

–Heat _________

•May require medical attention

–Heat stroke

•Medical_________

Factors Affecting Heat Injury

Consideration for Exercise

•Know signs/symptoms of heat illness

•Exercise in cooler part of the day

•Gradually _________ exposure to heat to _________

•Drink _________ _________, _________, and _________ exercise

•Wear _________ clothing

•Alter exercise _________ to stay within _________ zone

Implications for Performance

•Safety during events in high heat/humidity

–_________, season of the year

–_________ water stops

–Traffic control

–Identification of those with heat illness

–Coordinate proper treatment

•First aid, ambulance services, hospitals

Environmental Heat Stress

•_________ _________ _________ _________ (WBGT)

–Dry bulb temperature (T_db)

•Air temperature in shade

–Black globe temperature (T_g)

•Radiant heat in direct sunlight

–Wet bulb temperature (T_wb)

•Index of ability to wick sweat

Cold

•Important to protect against heat loss

–Maintain _________ temperature

•The _________ index

–Describes how wind lowers the effective temperature at the skin

Water

–Causes heat loss by convection _________ times greater than in air

Hypothermia

•Insulating factors

–_________

–_________

–Amount of insulation required is lower during exercise

Environmental factors

_________

_________

_________

__________

________

Insulation in the Cold

•Insulation

–Subcutaneous fat

–Clothing

–Amount of insulation needed is _________ during exercise

•Energy production increases upon _________ to _________

–_________relationship between VO₂ and body fatness

–Women cool faster than men

Factors Affecting Hypothermia

Effect of Water
Temperature on Survival

Changes in Insulation Requirement at Different Temperatures and Activities

Air Pollution

•Ozone

–Decreases VO_2max and respiratory function

•Sulfur dioxide

–Causes bronchoconstriction in asthmatics

•Carbon monoxide

–Binds to hemoglobin and reduces oxygen transport

•Prevention of problems

–Reduce exposure time

–Stay away from “bolus” amounts of pollutants

–Exercise during least polluted part of day

Effect of Carbon
Monoxide on VO_2max