KIN 100 1st Edition Lecture 8 Exercise 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 of exercise 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 stream faster 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 ventricle
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