Hydration & Sweat Testing

Question 1

What is the reference value for Euhydration in UsG?

Answer 1

< 1.020

Question 2

Why is urine colour a flawed indication of hydration?

Answer 2

Because there is many things that can alter the colour of urine
e.g. supplments, vitamins (berocca), foods (beetroot)

Question 3

Why is UsG not effective for acute intakes of low sodium fluid for a dehydrated athlete?

Answer 3

It can lead to large amounts of dilute urine
DESPITE the failure to fully replace the plasma volume of the individual

TLDR –> False negative for dehydration (masked dehydration)

Question 4

UsG cannot distinguish whether dehydration is??

(3 things)

Answer 4

Hypertonic - High sodium seen after physical exertion
Hypotonic - serum sodium and osmolarity are lower than normal due to sodium restriction –> but sodium loss is greater than water loss
Isotonic - loss of both water and sodium as a result of fasting or vomiting resulting in “normal blood/urine chemistry

Question 5

When is the UsG most valid? When is it not valid?

Answer 5

Valid - In the morning “on waking” following an overnight fast

Not Valid - as a pre-post event measure of hydration status where rapid changes in fluid balance have occured

Question 6

What are some protocol corrections needed for a fluid balance test?

Answer 6

• Fluid Or food intake
• Urine or faecal loss
• Residual urine in bladder
• Sweat losses captured in hair or clothes

Question 7

What is the limitations of the fluid balance assessment?

Answer 7

Doesnt take into account:
- Respiratory water loss
- Metabolic fuel loss (e.g. fat or glycogen stores)
- Decomplexing of water bound with muscle glycogen
- Metabolic water production

TLDR –> Body mass may change during exercise from factors other than water loss