(Final Exam) Pt.1 Temperature Regulation and Exercise

What is a normal body temperature?

• Skin temperature is closer to that of […]

• Internal body temperature remains relatively […]

• environment

• constant

Humans as Homeotherms

• Humans maintain constant body core temperatures.

• O2 transport, cellular metabolism, muscle contraction are NOT […] in hot and cold environments if the internal temperature is maintained.

• However, abnormal body temperature may have […] effects on the organism.

  • Cell damage with an internal body temperature >41 Celsius; […] and […] can occur.

  • Slow cellular metabolism with an internal body temperature

• impaired

• catastrophic

• heat stroke and brain damage

Thermal Balance

• Heat gain:

  • […] heat:

  •   […] heat: (radiation + conduction + convention)

  • Metabolic heat production is the rate of transformation of […] energy into heat

• Metabolic

• Environmental

• chemical

Thermal Balance

• Heat loss:

  • […] : loss or gain of heat in form of electromagnetic waves

  • […]: transfer of heat from the body to an object via direct contact.

  • […]: is the conduction of heat to or from air to water

  • […]: primary mechanism through which heat is lost during exercise.

  • Under normal, resting conditions, in a thermoneutral environment, most of the heat is removed by radiation.

• Radiation

• Conduction

• Convection

• Evaporation

How is body temperature regulated?

• Receptors will send information to […]

  • which will then analyze and process the information then responds

• […]:

  • vasodilation

  • sweating

• Cold:

  • […]

  • shivering —» increases metabolic heat production

  • catecholamine release —» increases heat production

  • Thyroxine release —» increases [….] rate —» increases heat production

• Hypothalamus

• Heat

• vasoconstriction

• metabolic

Prolonged submaximal exercise in cool environment

• Evaporate heat loss […]

• Convective loss […] slightly

• radiative loss is […]

• increases

• increases

• constant

Relationship between exercise intensity and core temperature during constant load exercise

• Rectal temperature is our internal temperature

• X-axis is our oxygen uptake

Heat index – a measure of how hot it feels

• Measure of […] of how hot it feels

  • interaction between relative […] and […] impacts perception of how it feels

• Example

  • Air temperature = 82 F, relative humidity = 80%

  • Heat index = 9 F (feels hotter than 82 F)

• High relative humidity and high ambient temperature […] body heat loss and […] body temperature

• body’s perception

• humidity and air temperatures

• lowers

• increases

Impact of a hot environment on sweat rate and core temperature during exercise

• Sweat rate […] (which is a good thing)

  • Because we retain all that heat in the body, what gonna happen to core temperature is going to increase dramatically.

• increases

Dehydration

• […] is excessive lost of body water.

• The […] the body water deficit, the higher the increase in physiological strain for a given exercise.

• Dehydration may result in further […] in core temperature (0.1 C to 0.2 C with each 1% of dehydration).

• […] mechanisms of heat loss (e.g., decreased sweating rate and cutaneous blood flow)

• May negatively affect exercise endurance performance.

• Dehydration

• higher

• increases

• Impaired

Consequences of Dehydration

• Dehydration by 3.5% before endurance exercise leads to:

  • Greater […] response

    • why because of cardiovascular drift

  • Exaggerate […] response

  • […] performance

  • Dehydration before […] exercise leads to:

    • a reduction in total work

    • a reduced buffer capacity

  • Full recovery of work occurs with rehydration

• HR

• Tre

• Reduced

• anaerobic

Assessment of Hydration Status

• Morning weight, urine, and thirst perception

  • If you lost more than 1% of day to day weight (indication of […] )

  • Urine color:

    • Pale urine = adequate hydration

    • Dark yellow urine = dehydration

    • sometimes vitamins can change color or urine

  • you feel thirsty —» […]

• dehydration

• dehydration

Counteracting Dehydration

-          […] of fluid is recommended for each pound of body weight lost.

-          During prolonged exercise: […] and […] with 5% to 10% of carbohydrates

-          Drinking water

• 0.5 L

• water and Sodium potassium

Fluid Replacement – Type of fluid

-          […] water can lead to exercise-associated hyponatremia.

-          […] can lead to nausea, vomiting, headache, extremity edema, and other severe symptoms.

-           More common in […] duration physical activities.

-           It can be prevented by a hydration plan.

• Overdrinking

• Hyponatremia

• long

Fluid Replacement

• Fluid intake in […] duration exercise does not influence body temperature

• After ~45 min, limiting fluids causes a rise in […]

• […] occurs around 40oC regardless of hydration status

  • doesn’t really matter during first half an hour.

• short

• Tre

• Fatigue

Heat acclimatization

• [….] is the improvement in heat tolerance that comes from gradually increasing the intensity or duration of work performed in a hot setting

• Heat acclimatization results in (compared with unacclimated):

  • Increase plasma volume

  • No change in plasma electrolytes

  • Lower body temperature

  • Lower exercise HR

  • Earlier onset of sweating and greater sweat rate Lower lactate during submaximal exercise 

  • Improved exercise performance

  • Increased cellular heat shock proteins (prevent cellular damage due to heat)

• Heat acclimatization

Impact of heat acclimation on heart rate and core temperature during exercise

Exertional Heat Cramps

• Exercise-associated muscle cramps (EAMCs)

• Painful [….] muscle contractions or spasms.

• Possible contributing factors: fatigue, […] , hydration status, or electrolyte concentration.

• […] and dietary sodium chloride may prevent or mitigate EAMCs.

• involuntary

• neuronal excitability

• Oral hydration

Heat Syncope

-          Is temporary loss of […], to heat, typically those who are physically unfit.

-          Temporary […] failure.

-          Physical unfit, sedentary, unacclimatized individuals are at risk.

-          Symptoms may vary from light-headedness to loss of consciousness.

-          […] recovery once individuals lay supine.

• consciousness

• circulatory

• Rapid

Heat Exhaustion

-          […] to exercise in a hot environment.

-          Most common form of serious heat illness.

-          Heat exhaustion is defined as the incapacity to perform exercise in the heat due to a combination of factors, such as […]

-          Body core temperature (usually <40.5 C).

o   Very close to […]

-          Oral fluid for conscious individuals who are not losing fluid (vomiting or diarrhea).

-          IV fluid administration is recommended for those unable to ingest oral fluids or have severe dehydration.

• Inability

• cardiovascular insufficiency, hypotension, energy depletion, and fatigue.

• hyperthermic

Exertional Heat Stroke

• Exertional heat stroke is caused by […] (body temperature >40oC), profound CNS dysfunction, multiple organ system failure that result in delirium, convulsion, or coma.

  • Delirium is acute changes in cognition

  • […] describes uncontrolled body movements and controlled muscle movements or muscle contraction

  • coma

• Greater risk with high-intensity exercise of short duration or prolonged exercise when WBGT > 28oC (82oF).

• Immediate and effective whole-body cooling is required (e.g., cold water, ice water immersion therapy).

• Supplements that contain stimulus:

  • It can increase […]

• Risk factors: low physical fitness, excess adiposity, improper clothing, incomplete heat acclimatization, illness, and supplements that contain stimulants.

• hyperthermia

• Convulsion

• metabolic heat production

Exercise in Cold Environments

Cold Stress and performance

• Cold temperatures can […] impact sports performance

  • Hands exposed to cold temperatures often become […] due to reduced blood flow and depressed rate of neural transmission

  • Reduction in […] transmission and blood flow to hands results in loss of dexterity and negatively impacts motor skills

  • In general, cold temperatures can lead to […]

• negatively

• numb

• neural

• hypothermia

Hypothermia

• […] develops when heat loss exceeds heat production causing a negative heat balance (core temperature)

  • Occurs when temperatures drops below 34-35 degrees Celsius

• Conditions that predispose individuals to hypothermia:

  • Water immersion

  • Rain

  • Wet clothing

  • Prolonged exposure L

  • Low-ambient temperature with wind

  • Inappropriate clothing 

  • Hypoglycemia

• Advanced age (>60y)

• Low body fat

• Hypothermia

Hypoglycemia

• §  Risk for kids with […]

• §  Decreased in glucose you become hypoglycemic

• §  […] shivering

• §  So you lose that involuntary physiological mechanism by which you increase metabolic heat production.

• §  It also causes […] and promotes sweating.

• §  Cold environment vessels are supposed to constrict because we want to retain

• §  Hypoglycemic promotes vasodilation and sweats

  • Bad because sweat = losing heat from body.

• diabetes

• Impairs

• vasodilation

Advanced age (>60y)

§  Because lower metabolic rate = […] heat production

§  Losing muscle = […] metabolic rate

• lower

• lower

Wind Chill temperature (WCT)

-          WCT integrates wind speed and air temperature to provide an estimate of […] of the environment.

-          FOR FROSTBITES

-          Don’t pop the blisters, but rewarm the tissues is recommended so that most of the tissue survives.

-          Sometimes tissues do not […].

• cooling power

• survive

Cardiac and Respiratory Considerations

-  […]

o    Condition that provoked only by exercise

o   Those who have EIB at baseline their respiratory function is fine.

o   90% of people with asthma also experience EIB.

-  […] respiratory tract viral infections

• Exercise-induced bronchoconstriction (EIB)

• Upper

Acclimation to cold environments

-  […] ability to maintain a higher hand and foot temperature during cold

o   Improved peripheral blood flow

-  […] adaptations occur rapidly (within first 7 days of chronic cold exposure).

• Improved

• Cold