L3 & L4: Heat stress

Question 1

What determines variation in core temperature during a fixed intensity?

Answer 1

1. Genetics
2. Acclimation
3. Fitness

Question 2

What is the range of temperature seen during exercise?

Answer 2

37.6 - 39.2 degrees

Question 3

What is stress and what is strain?

Answer 3

Stress is the environmental factors put on an individual which includes temperature, humidity and altitude.

Strain is the physiological response to stress put on the body. This includes heart rate, sweating and core temperature increase.

Question 4

Who was the first person to die of heat illness in sports?

Answer 4

Francisco Lazore in 1912

Question 5

What can Heat illness cause other than heat related disorders>

Answer 5

Acute injury due to increase risk of unsafe acts this can also lead to musculoskeletal injuries.

Question 6

What can long term exposure to heat stress cause?

Answer 6

Increase risk of kidney disease

Question 7

what happens to the kidneys during heat stress?

Answer 7

Exposure to heat stress causes dehydration from sweat production and increase blood flow to the skin. Reduce water in the blood causes low blood pressure.

Vasopressin increases in response to low BP which causes water retention and subsequently increase urine concentration which has been associated with ischemic kidney disease.

consistent Renal vasoconstriction has also been shown to reduce kidney function long term.

Question 8

What factors influence Heat illness prevalence?

Answer 8

1. Seasonal
2. Lack of experience and inefficient behaviour
3. Age including medication, underlying health problems, reduce sweating ability and reduce fitness.

Question 9

Why is it harder to cool down in high temperature and humidity?

Answer 9

Humidity at high temperature has a higher total vapour pressure due to the increased kinetic energy in the atmosphere. The difference between skin vapour pressure and ambient vapour pressure determines the ability of evaporative heat loss.

Question 10

Describe the relationship between temperature and mortality in the uk compared with Spain.

Answer 10

Mortality from temperature is highest at cold temperatures <10 degrees however also increases beyond 29 degrees. The lowest deaths are seen at 28 degrees. In Spain the lowest deaths are seen at 31 degrees due to acclimatisation and beyond this mortality increases.

Question 11

How is climate change effecting the temperature?

Answer 11

Temperature shifting to the right, extreme heat events are increasing and variation in temperature is greater than ever before.

Question 12

Whos most at at risk of heat related illness?

Answer 12

Older individuals and really young

Question 13

Why are the really young (<4 years) at risk of heat illness?

Answer 13

1. Not fully developed thermoregulatory systems
2. sweat distribution is inefficient
3. Small surface area relative to volume (poor heat loss)

Question 14

What is the greatest contribution of heat death in children?

Answer 14

Being left in the car

Question 15

How does Fitness impact heat loss?

Answer 15

1. Maximal VO2 decreases with age, thus for a given intensity it becomes more intense = increase sweat
2. Sweat production decreases particularly in peripheral areas such as legs and arms.
3. The number of sweat glands remain the same.

Question 16

How does heart rate and maximal heart rate impact heat loss?

Answer 16

Age reduced maximal heart rate whilst untrained individuals require a higher VO2 for a given intensity. Subsequently heart beat reserve is reduced. This means less available heart beats for thermoregulatory responses.