The Role of Iced Drinks in Recovery
It is a pillar of sports nutrition. Without it performance would suffer a great deal, especially in hot climates. Hydration. Most people have heard of the saying "A 2% drop in hydration leads to a 10% drop in performance". In this blog post I am going to look at iced drinks/slurry and how they can possibly aid athletes in thermoregulation as well as hydration and recovery.
Whats The Problem?
First lets look at why swimmers may be at specific risk for dehydration and heat related illness. Poolsides are hot places and often very humid and as they are indoors there is no wind present . These factors all add up along with exercise leading to increased core temperature. Normally when our core temperature rises we sweat in order to cool off by drawing heat to the skin surface and then evaporating the sweat off the skin to cool us down. However there are factors that can influence sweating efficiency including;
1) Humidity of environment
2) Presence of wind
In a humid environment it is less likely for sweat to evaporate from the skin surface as the environment already has lots of water molecules in the air and because water moves from high to low concentrations it is unlikely to evaporate into air that already has a high concentration of water. This means that the sweat on your skin is not doing its job and will not cool you down.
In windy environments the wind will pick sweat up off the skin and like evaporation take heat away from the body. However in still conditions this won't happen, again rendering the sweat as useless.
Even though the sweat we produce in these conditions doesn't work, we will still produce the sweat, especially if we are unaccustomed to the conditions. Therefore not only is it damaging for thermoregulation but it can also lead to dehydration.
So Why Iced Drinks?
There has been research carried out by a few research groups, as summarised in the review by Ollie Jay and Nathan B. Morris (see references). They show that while iced drinks may not help in dry and windy conditions as they take away from sweat efficiency they can be used in hot, humid and still conditions where sweat efficiency is already compromised. In these conditions iced drinks tend to lower core body temperature.
Another good point to make here is that although there are many methods to cool down there aren't many that hit two birds with one stone; providing a cooling mechanism as well as a way to stay hydrated. All you need to make the drink is water, ice and a blender to finely crush the ice. Storage would be ideal in a thermos flask to keep it icy on the poolside, (you could also add squash to increase palatability and promote further drinking).
Stretching the Science
What about using this science to accompany some methods already used in recovery when there is a quick turn around between heats and finals? There is already research into using chocolate milk as a recovery aid following exercise, for example the paper from Michael John Saunders (see references) shows how chocolate milk can be used efficaciously in post exercise recovery. Could the two solutions (iced drinks and chocolate milk) be used together to provide recovery along with a thermoregulation strategy in one drink? There is no reason why this shouldn't work and although there are no papers published yet on the idea the theory certainly adds up.
Ollie Jay , Nathan B. Morris
Sports Med (2018) 48 (Suppl 1):S17–S29
Saunders, Michael John
Current Sports Medicine Reports: July 2011 - Volume 10 - Issue 4 - p 203-210