Lecture 9 - Environmental Physiology

Question 1

What happens with cooling and its subseqent effect on performance ?

Answer 1

Cooling done prior to warming up for the event or competiton. This lowers core temprature. When exercises is done to increase the muscle tempreature the core temprature remais at a lower level then it would have done. Whilst core temp does gradually increse during exercise it remais at a lower temprature that if no cooling was applied berfor hand, therefore ensre better perfoemcne by sustaing ppower output and intermmitedn ability.

Question 2

With increases in heat what happens to the performance quality of the 100m, 200m, 400m, 800m, 1500m, 5000m, 10000m and the marathon?

Answer 2

• 100m, 200m and 400m times impromve.
• 800m only slightly decreses
• 1500, 5000, 10,000 and marathon significantly decreases.

Question 3

With sports that play multiple matches in one day what is an issue with this and how it relates to core temprature?

Answer 3

With each sucsessive activity, even if it is seprated by a few hours core temprate does not complety return to its natural resting level, meaning that during the exercise it can reach a higher, and therfore peformance degrading level easier.

Question 4

What is the loss rate in heat acclimation adaptions after coming out heat acclaimtion training for HR, sweat rate, overall adaptations ?

Answer 4

Each day there is a 2.5% reduction in HR adaptions

The longer the period of heat acclimaion the less decay there is in sweat rate.

Question 5

What are the causes of heat gain, production and dissapation during exercise on the body ?

Answer 5

Heat gain

• Solar radiation
• Ambiet temp and humidity
• Reflected solar and ground radiation

Production

• Contracting muscle
• Core temp

Dissipation

• Evaporation
• Convection
• Radiation

Question 6

Describe the components that make up each section of the conceptual heat balance equasion, their sub catagoes if they have any and what each of the following letters emans and where it fits ?

M, W, K, C, R, Esk, S, H

Answer 6

Made up of three main components.

• Rate of head produced (M-W) = Rate of total heat loss (K+C+R+Esk) + Rate of heat storage ( S ).
• Rate of total heat loss splits into Dry heat loss ( H ) and evaporation from Skin ( Esk )

M = Rate of metabolic heat production

W = Rate of mechanical work

K = Rate of conductive heat

C = Rate of convective heat loss

R = Rate of radiative heat loss from the skin

Esk = Rate of evaporative heat loss from the skin

S = Rate of body heat storage

H = Dry heat loss

Question 7

What are the four classic markers of good heat acclimation preperation?

Answer 7

• Lower HR
• Lower Core temp
• Higher sweat rate
• Enhanced performance capacity in the heat.

Question 8

Of the pre-cooling methods whihc is best ?

Answer 8

A mixed method cooling, ice baths, ice drinks, ice vests, cold towels.

Question 9

Is there another method of cold substance being applied that can improve performance ?

Answer 9

Spraying cold water on to the face. Whilst it does not change skin temp like cold baths it did result in a change in thermal sensation reported on the skin.

This has the same level of benificial effect as other coling methods.

This mid cooling effect has also been shown to be a pbetter impromvner of perofmcne as it is lily the percpetion of tmeprature and pain that limts capacity. It has also been shown to allow better reprated sprints in footballers with ice packs and ice drinks.

Question 10

What are the three methods of cooling that are used?

Answer 10

• Ingest
• Immerse
• Apply

Question 11

For exercise in the heat what s the No1 intervention to use?

Answer 11

Heat acclimation

Question 12

Give an example heat aclimatisation and acclimation sessions to be performed ?

Answer 12

Aclimatisation

Outside - Running at a self selcted rate that is achivalble to 60-90 mins at 40celcius

Inside - cycle ergometer at 60%vo2max for 60-90 mins at 40 celcius

Acclimation

Passive heating- passive heating and post exercise temrpatre maiaintnace. hot water bathing sauna 45-60 mins

Contorlled hyerthermia - perfoming rest and exercise to mainaint core tempp at 38.5 for 60-90 mins

Controlled intensity- cycle ergomenter at 65%vo2max HR for 60-90 mins at 40celcius.

Question 13

What changes does the heat cause to the following systems?

• Respiratory
• Neurological
• Muscular
• Cardiovascular
• Psychologcal

Answer 13

Respiratory - Increased ventiation, increased Paco2, Increased acidity, breathelssness,

Neurological - cerebral substrate depeletion, altered brain neurotransmitter levels, increased brain temp, decresed O2 delivery.

Muscular - Impainred function due to reduced delivery, metabolite accumalation, affert feedback

Cardiovascular - Reduced SV, incresed skin perfusion and temp.

Psychological - motivation and pain tolerance decreases.

Question 14

List the thermoregulatory and performance adapations from heat acclimation.

Answer 14

Question 15

What is the conceptual heat balance equation?

Answer 15

Rate of heat produced = (Rate of total heat loss + Rate of heat storage)

Question 16

With acclimaton when it is suggested this is done througout a season?

Answer 16

Performed early in season and then topped up periodically as body remebers some of the effects and takes less time to acclimate next time.

Question 17

What are some important conciderations for heat acclimation lengths and exercise performance during ?

Answer 17

• Need to be at least 7 days if only core temp and Hr changes are requred
• Need to be at least 14 days if sweat responce changes desired
• Exercise intersity must be monitered to ensure that the thermal impulse is sufficient to allow adpatatio to occure and continue,.

Question 18

With the knowledge that a long distance race is going to be performance in very hot conditions what three considerations need to be addressed ?

Answer 18

• Realism - with the increses in WGBT you need to make the ahtelte aware that they are unlkelyy to run a PB
• Prepare - You need to look at the holstorcal data avalable from thoes conditons to enure that the atheles is acclimated on race day. - Specificity
• Measure the WGBT in race day and be prapered to modify practive on race day (If pre cooling facity are avalabel use them, and do not perofce ecsessive warm ups.

Question 19

What is WGBT ?

Answer 19

Wet bulb globe temprature Its it the measure used to esutmate the actially tempratre effects on humans from sunlight, humitity, wind chill ect.