water 1 readings

Question 1

Jones et al 2010

Answer 1

what is the best rate of drinking to rehydrate following exercise

100% volume replacement following exercise with either bolus or metered drinking

metered drinking = less urine produced therefore more drink retained

Question 2

Shirrefs et al 1996

Answer 2

what is the optimal volume and composition of fluid for rehydration

low Na group and high Na group
with 50%, 100%, 150% and 200% volume drinks
urine samples collected before and for 7 hours after

needed to consume volume of fluid which was greater than the volume lost, at least 150%
needs a sufficiently high Na content otherwise fluid will just be lost as urine

Question 3

Shirreffs and Maughan 1998

Answer 3

what is the optimal concentration of Na for rehydration in drinks

exercise to depleat to 2% bw loss
consumed 150% lost vol
0, 25, 50 or 100 mmol/l Na
measured vol of urine produced

inverse relationship between Na content and vol of urine produced

Question 4

Clayton et al 2014

Answer 4

does addition of 2% or 10% CHO to drinks improve hydration

dehydrated to 2%
rehydrated with set vol of 2% or 10% drink
blood and urine samples

greater proportion of 10% drink retained
= better fluid balance from 120 mins post exercise onwards

Question 5

James et al 2013

Answer 5

does adding milk protein to drink enhance rehydration

dehydrate to 2%
60g/l carb drink
40g/l + 20 g/l milk protein
20 g/l + 40 g/l milk protein

carb + milk protein drinks were better retained than carb only
higher amount of milk offered no further benefit

Question 6

James et al 2012

Answer 6

does addition of whey protein to a carb electrolyte drink

dehydrate to 2%
rehydrate with 150% of 60g/l CHO or 50g/l CHO + 15 g/l whey
urine samples before and 4 hours after

no difference in net fluid balance so no benefit