Exercise in the heat

Question 1

What is WBGT?

Answer 1

A type of apparent temperature used to estimate the effect of temperature, humidity, wind speed, and visible and infrared radiation on humans

Question 2

What considerations should be taken when approaching exercise in the heat?

Answer 2

Realism- no PB is going to happen when WBGT is too high

Research and prep for the most extreme historical WBGT reported in past years

Specificity- measure WBGT on race day and prepare accordingly

Question 3

What is the conceptual heat balance equation?

Answer 3

Heat production (M-W) = Heat loss (K+C+R+Ske) +_ heat storage (S)

Heat production- how much metabolic heat remains after performing physical work. Linearly related to oxygen consumption.

Heat loss- occurs via dry heat loss temp gradient between skin temp and ambient temp. Or via wet skin loss gradient between skin and air (w).

Where: 
W- rate of mechanical work
M- Rate of metabolic heat production at
K- Rate of conductive heat loss
C- Rate of convective heat loss 
R- Rate of radiative heat loss
Ske- Rate of evaporative heat loss from skin
S= Rate of body heat storage

Question 4

What are the key effects of heat on fatigue?

Answer 4

increased core, skin and cerebral temperatures act to change cardiovascular function- reduced oxygen delivery and extraction at the working muscles.

Question 5

What are the four main benefits of heat acclimitisation/acclimation?

Answer 5

Decreased resting HR and core temp

early onset of sweat and improved sweat rates

Enhanced performance capacity

Question 6

What considerations must be taken when planning a heat acclimation strategy?

Answer 6

Must last at least 14 days to receive benefits

progression overload required to ensure physiological adaptations continue to occur

Re acclimation requires less overall sessions to receive benefits

Be sports specific (as much as possible during acclimation)

Prepare for the worst WBGT

Question 7

What are the proposed benefits of pre and mid cooling ? and limitations of both?

Answer 7

pre cooling- best performed via mixed method approach- reduces core temp prior to, and attenuates increase during exercise

Mid cooling- reduces thermal sensation

both strategies can be hard to practically implement due to time constraints and funding etc

• pre cooling needs optimisation
• paucity of research on elites