KIN 100 1st Edition Lecture 8Exercise and the Environment ○ Temperature○ Pressure(Altitude decrease, diving, increase)○ Air pollution● How is heat transferred?○ Conduction■ heat transfer by contact● air, water, within body (blood stream)○ Convection■ particle movement● air- cyclist● water- swimmer○ Radiation■ heat transfer without transfer medium● vacuum● from the sun● affected by color○ white- least heat exchange○ black- most heat exchange○ Evaporation■ heat exchange by water loss● air limits H2O absorption● relative humidity○ total moisture air can absorb● Sweating- major heat loss mechanism○ max rate 1-2 liters/hour● Breathing● aided by convection● sweating doesn’t cool- evaporation does● sweat must be replaced● hyperhydration- excess water intake in preparation ofexercise● Environmental Issues○ Exercise in Heat● worst high temp, high humidity● dehydration○ body’s thirst awareness mechanism imperfect■ already dehydrated when start feeling thirsty● fluids○ water- main fluid replacement● electrolytes○ sodium etc● cold fluids are emitted from stomach to blood streamfaster○ other ingredients, high sugar, impede absorption● glucose polymer drinks○ enhance absorption into bloodstream○ carbohydrate replacement■ gatorade■ Heat Illness● heat cramps○ involuntary muscle spasm○ muscle salt/water imbalance■ Heat exhaustion● buildup of heat in body○ weak pulse○ high HR○ profuse sweating■ Heat Stroke● temp control failure○ hyperthermia○ no sweating- not cooling○ potentially fatal■ renal failure■ cardiac failure■ neural damage■ Treatments● fluids● cold temps● drugs○ Exercise in the cold■ frostbite● skin damage● appropriate clothing● head heat loss 30-40% of total heat loss○ hats○ Exercise at altitudes■ lower barometric pressure■ decrease in O2 in blood■ decrease plasma volume■ predominantly affects endurance■ Treatment- more O2○ Acclimatization■ adjusting to a new environment● Heat adjustments○ increase blood volume○ earlier sweat onset- less O2, harder to sweat○ sweat output increases- sweat more○ increase skin blood flow● Altitude adjustments○ increase O2 carrying capacity○ increase blood volume○ increase # of red blood cells■ polycythemia (EPO)● stimulates erythrocytes-red blood cells● Benefits lost after 2-3 weeks after return to sea level● “Live high, train low”○ Air pollution■ CO● competes for hemoglobin better than O2○ can’t get O2 to brain■ Ozone (O3), Sulfur dioxide (SO2)● can cause airway to narrow● exercise induced asthma○ Microgravity■ disuse atrophy■ decrease in ● strength● exercise capacity● heart size○ blood volume○ left
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