Heat Stress and Hydration Flashcards
Why does heat stress impair endurance performance but not maximal strength?
a) Maximal strength relies on anaerobic pathways, which are less affected by heat
b) Heat stress only affects central fatigue in aerobic efforts
c) Endurance performance depends on sustained core temperature regulation
d) Two of the above
d) Two of the above
Maximal strength relies on anaerobic pathways, and endurance performance requires sustained thermoregulation Core temperature rises until it inhibits central nervous system drive**
Uncompensated heat stress primarily limits performance by affecting the central nervous system .
How does uncompensated heat stress limit exercise performance?
a) Increased sweat rate causes muscle glycogen depletion
b) Core temperature rises until it inhibits central nervous system drive
c) High plasma osmolality reduces oxygen delivery to working muscles
d) None of the above
b) Core temperature rises until it inhibits central nervous system drive
Uncompensated heat stress limits performance primarily by affecting the CNS due to rising core temperatures .
Why might slower marathon runners experience greater performance decrements in high temperatures?
a) Their pace results in prolonged exposure to heat
b) They produce less sweat, reducing cooling efficiency
c) Their VO2 max is lower, limiting thermoregulation
d) All of the above
a) Their pace results in prolonged exposure to heat
Slower marathon runners are exposed to heat for a longer duration, increasing the cumulative thermal load .
What is the primary cardiovascular consequence of dehydration during exercise?
a) Increased stroke volume
b) Decreased cardiac output
c) Enhanced central blood volume
d) None of the above
b) Decreased cardiac output
Dehydration reduces plasma volume, lowering cardiac output and impairing exercise performance .
What mechanism explains impaired skilled performance at 2% dehydration?
a) Increased blood viscosity reduces peripheral motor control
b) Reduced plasma volume affects decision-making capacity
c) Central fatigue increases subjective effort and reduces accuracy
d) None of the above
c) Central fatigue increases subjective effort and reduces accuracy
What physiological marker is most associated with reduced aerobic performance in dehydration?
a) Increased heart rate
b) Increased blood viscosity
c) Decreased plasma volume
d) Two of the above
d) Two of the above
What is the major adaptation during heat acclimation?
a) Reduced plasma osmolality
b) Increased plasma albumin concentration
c) Enhanced mitochondrial biogenesis
d) None of the above
b) Increased plasma albumin concentration
How does post-exercise protein ingestion enhance heat acclimation?
a) By increasing sweat rate during exercise
b) By promoting plasma volume expansion through albumin synthesis
c) By decreasing core temperature during subsequent exercise
d) Two of the above
b) By promoting plasma volume expansion through albumin synthesis
What is the recommended fluid intake strategy for rehydration within 4–6 hours post-exercise?
a) Consume fluid equivalent to 100% of sweat loss
b) Ingest 1.5x the volume of sweat lost
c) Combine water and protein to prevent gastric distress
d) None of the above
b) Ingest 1.5x the volume of sweat lost
Rehydra.5x the fluid lost compensates for continued fluid loss through urine and sweat.
Why might chocolate milk be an effective post-exercise rehydration strategy?
a) It contains carbohydrates, protein, and electrolytes that enhance fluid retention
b) Its osmolality increases gastric emptying
c) It prevents central fatigue by increasing blood glucose levels
d) None of the above
a) It contains carbohydrates, protein, and electrolytes that en retention
Chocolate milk provides a combination of nutrients that support rehydration and glycogen resynthesis .
What is the optimal carbohydrate concentration in a beverage for exercise lasting >90 minutes?
a) 3–5%
b) 5–8%
c) 9–12%
d) None of the above
b) 5–8%
Carbohydrate concentrations in this range optimize gastriand energy availability during prolonged exercise .
Which physiological adaptation is most beneficial for prolonged aerobic exercise in the heat?
a) Reduced heart rate during submaximal exercise
b) Increased sweat sodium concentration
c) Enhanced stroke volume at rest
d) None of the above
a) Reduced heart rate during submaximal exercise
Heat acclimation reduces huring submaximal efforts, decreasing cardiovascular strain .
Which of the following conditions requires electrolyte replacement during exercise?
a) Low sweat rate and exercise <60 minutes
b) Exercise >90 minutes with high sweat sodium loss
c) Moderate exercise with 2% dehydration
d) None of the above
b) Exercise >90 minutes with high sweat sodium loss
Electrolyte replacement is necessg-duration exercise, particularly in athletes with high sweat sodium losses .
Why does heat stress increase cardiovascular strain?
a) Increased skin blood flow reduces stroke volume
b) Plasma osmolality decreases, limiting oxygen delivery
c) Elevated core temperature inhibits muscle glycogen use
d) Two of the above
a) Increased skin blood flow reduces stroke volume
Heat stress increases blood flow to the skinvenous return and stroke volume .
What is the recommended pre-exercise hydration strategy?
a) Drink 5–7 ml/kg body weight at least 4 hours prior to exercise
b) Consume 3–5 ml/kg immediately before exercise
c) Drink to thirst in the hour leading up to exercise
d) All of the above
a) Drink 5–7 ml/kg body weight at least 4 hours prior to exercise
This strategy ensures adequate pre-exerion without risking gastric discomfort .
