Hydration is key. I am sure many of us have heard this during exercise or performance. That quote really is the absolute truth. Our bodies are made up of more than 50% water so it’s no surprise that proper hydration of our bodies is vital to getting the most of of ourselves. Even slight signs of dehydration can be detrimental to our performance. Though many may believe that dehydration affects only endurance athletes, this is false. Improper hydration levels can affect power and sprint sports as well. Sometimes it is not enough to be hydrated prior to exercise, but to also be consuming water during and after as well. If we know this information on fluid levels to be true, then how can we prepare ourselves so that we do not find ourselves in a hole?
Hydration and the Body:
So how does hydration help us even outside of sport and performance? It is no secret that without water, humans can only survive for a few days. Slight decreases in fluid levels can bring changes even to our brain! The brain is made up of more than 80% water, and dehydration can bring upon mood changes as well as changes in alertness and concentration. Aside from our brain, almost every system within our body is also affected. An additional system that is affect is our body’s circulatory System. Water helps us to regulate our body’s core temperature. When our core temperature rises above our normal thermoregulatory rates, additional stress is placed upon us which can impede our energy systems. This adjunct effect on our energy systems can decrease both performance and recovery.
Hydration levels also help to regulate our body’s blood pressure. Being in a state of dehydration makes your blood more viscous, or thicker. When your blood becomes “thicker” this increases your heart rate since it takes more effort for your heart to pump the blood throughout your body. With the increased heart rate, coupled with a decreased amount of blood in your body, this yields a fall in blood pressure.
Without water, we would not be able to properly carry essential nutrients to different systems of the body. It also aids in the removal of waste. Water helps to rid of blood of waste and since it is the majority of the makeup of our blood, helps to ensure that our cells are receiving the proper nutrients.
Dehydration also affects the body’s ability to process fat into the muscle. With this energy transport limited, the body uses up the available glycogen that is present.
Hydration and Performance:
Now looking at hydration from a sports perspective we can start with a known fact: losing as little as 2% of body weight in fluids can have diminishing effects on an athlete’s performance. Take for example a female endurance runner weighing 125 pounds, losing 2.5 pounds of fluids in body weight will yield a decrease in performance. If many of us went and ran 8 miles on a humid, 90 degree day and weighed ourselves before and after exercise we will most likely have lost well more than 2.5 pounds. Now take that level to a loss of 3% in body weight, and you are entering the realm of heat exhaustion or heat stroke.
During exercise, an athlete can sweat various amounts. Typically, athletes can lose anywhere from 5-10% of body weight during a competition. If not replenished, we can see the diminishing effects that would have on our ability to perform.
Aside from stating that athletes can experiencing diminishing effects, let’s take a look at some of the specifics. When in a state of dehydration, our body’s ability to produce a high cardiac output is altered. This means that our heart is unable to pump at its highest capacity during exercise activities. This decrease in cardiac output also effects of body’s ability to perform at VO2 max efforts and increased fatigue with increased effort.
We can also experience a decrease in our skin’s blood flow. What does this mean exactly? Well, when we experience vasodilation of our blood vessels (when they open) it is an essential mechanism for the transport of heat from our body’s core to the periphery. When this happens, we rely on our body’s sweat and the process of evaporation to take away heat from the surface of our skin. This physiological mechanism occurs to allow our bodies to function for effective temperature regulation. When exercising in the heat, and not properly rehydrating, this process is alter are we then become “overheated.” Our body cannot effectively keep our core temperature regulated.
As stated previously, dehydration affects our bodies ability to transport essential nutrients. This is highly important during performance as our energy systems are altered. When our body uses up our glycogen stores quickly (due to hydration as we discussed earlier) our muscles no longer have readily available energy to continue working. When asking our bodies to perform under fluid restriction, we undergo stress on both the cellular and whole body. When our glycogen stores are completely used up our body then relies on our fat stores as a source of energy.
Knowing some of the effects that dehydration can bring an athlete, implementing a hydration plan can be just as important as a nutrition strategy. When deciding how much fluids you should be taking on, always keep in mind the duration and intensity of the exercise you are performing. It is always best to keep in mind that thirst is NOT a good indicator of hydration status. When you begin to experience thirst, know that you are already experiencing effects of dehydration. It is also best to remember that you may need to continue drinking even past the point of when you feel quenched. You may still be in a deficit of 25-50% hydration levels.
It is also good to point out that as the saying goes, “water follows where sodium goes.” Sometimes it is necessary to consume a sports drink of nutritional drink that contains sodium to ensure that your muscles are receiving the proper amounts of fluids. If consuming only water, most will be excreted through the urine as waste. Not all fluids consumed should include sodium, but drinks taken prior to high intensity exercise should have a small source of sodium. Some helpful tips are as follows: - 17-20 fluid ounces 2.5 hours prior to exercise - 7-10 ounces every 10-20 minutes during exercises - at least 8 ounces of water post-exercise
Hydration may be the key to success! If our bodies are made up of more than 50% water, why not keep it that way! Starting a performance or training day at full hydration levels can play a major impact on the outcome. So why not get ahead with a simple secret of fluid intake. It may be the differences between seconds, or whether you are the one who gets to the finish line.