With the hot season in most parts of the country beginning it is very important to take extra steps to stay hydrated. The majority of our body is comprised of water and all cellular reactions require it as well. This means that our athletic performance is largely dependent our ability to stay hydrated.
We are all probably well aware that it is important to stay hydrated but do you know the effects of dehydration on on some of the body systems? Let's look at a couple of the very important effects that lack of hydration can have on our performance.
From a cardiac standpoint, when we are dehydrated, blood volume is lower. Reduced blood volume leads to decreased volume of blood per stroke by the heart (stroke volume) and in order to maintain the same cardiac output, heart rate (HR) will have to increase. In addition, the lower blood volume will also lead to lower blood pressure (BP). Low blood pressure results frequently in lightheadedness, fatigue, and syncope (passing out). With the heart serving to pump nutrients to the muscles, and much of blood being comprised of water, you can see how important hydration is to the cardiac system.
Metabolically, we need water to aid in the digestion and breakdown of foods and other sources of energy. Thermal regulation is controlled greatly by the brain but also by sweating. When we are dehydrated, we produce less sweat and therefore cannot cool the body. The worst possible result would be that sweat production stops, leading to increased internal body temperature and overheating in the thermal controls of the brain. The end result of this is heat stroke which is a very serious situation.
There are many other effects of dehydration but these are probably the most immediate to us as athletes. Dehydration is an element of our performance that we can control and therefore it should be of focus going into hotel climate training and races.
Here are few tips for hot weather training and racing:
Alternate between water and electrolyte drinks. We need the electrolyte to help retain water.
Use salt tablets the week of AND during hot weather training and racing. Preloading with these helps to ensure that we are more hydrated going into the training and racing.
Drink when you swim. Often times we forget that we sweat in the water when we swim and this can be an easy way to forget and get dehydrated.
Simulate the race condition in weeks leading up to race. If traveling to a hot weather race we need to stimulate the adaptations of the body prior to traveling so it reacts optimally on race day.
Reduce diarrhetic consumption in the week leading up to a race. Caffeine and alcohol are both diarrhetic and therefore contribute to dehydration. Coffee may be hard to drop but maybe just one cup less per day on race week.
Stay hydrated and enjoy the performance benefits.