Environmental factors and performance (topic 8) Flashcards
describe the prodction of heat in the body
when breaking down food (break bonds) it releases energy, muscle contractions are 20% efficient with 80% being released as heat
what is the role of the hypothalamus in body temp. regulation?
it regulates the body temp by vasodilation (skin blood vessels) so more heat is lost across the skin, and sweat glands become more active
outline the four physical processes of body heat loss
conduction: movement of heat through the body tissue to the surface
convection: moving heat from one place to another through air or water(blood)
radiation: transfer of energy waves that are sent out from one object and absorbed by another (the sun)
evaporation: sweat from liquid to water vapor (main body heat loss)
explain the aspects of the acclimatization process
acute response: changes in core temp and HR (5 days)
chronic response: onset of sweating/rate,
what are the factors that affect individual heat stress
lack of acclimatization, low fitness, large body mass, dehydration, age
What is heat illness
hyperthermia, that comes with exercise in the heat (hyperthermia, heat exhaustion, and heat stroke)
What makes in hard to exercise in the cold
body comp., body size and training status, make it hard to cope with cold exposure. Your heart harder to just keep you warm meaning their is less capacity to exercise
What is wind chill?
increase of heat loss because the warm bubble around is gone bc wind gets cold sometimes
What is the CLO unit?
the amount of thermal insulation in an outfit that will keep a person comfortable in a room at 70°F with normal ventilation
What is the most important mechanism of heat dissipation?
sweating
what is a concern when losing body fluid through sweating?
dehydration
what are chronic adaptations to exercise that can improve performance in the heat
increase plasma volume
earlier onset of sweating
more dilute sweat composition
reduced rate of muscle glycogen
decreased psychological perception of effort
what is hypothermia
low body temp. that had different clinical categories depending on severity
what is body composition
What are the three adaptive responses by which your body regulates itself in cold environments?
habituation: desensitization of the normal response to cold
Metabolic Acclimatization: greater shivering response to increase heat production
Insullative Acclimatization: increased vasoconstriction to enhance heat conservation
