27 Feb Hydration
Why stay hydrated?
Water is the component of the body, representing 45% to 75% of a person’s body weight. It might also interest you to know that we can only survive a few days without water. That being said, fluid levels in our body are constantly fluctuating as we lose or gain water. In the body water acts as a lubricant, shock absorber, building material as well as a solvent. Athletes must monitor hydration status since sweat losses that surpass fluid intake can quickly lead to a hypohydrated state.
We’ve all seen the popular Gatorade commercial- As the emaciated and completely withdrawn marathon runner struggles relentlessly to cross the finish line, only to find themself completely losing gross motor control; she then collapses and struggles to crawl in a last ditch effort to test the limits of the human movement system (HMS). We have always understood that Na+ hydrates the HMS at the cellular level and allows the Central Nervous System (CNS) to function successfully. The majority of our perspiration is Na+ however, depending on the athlete may vary. Human beings are homeotherms, which attempt to maintain a constant core body temperature for survival. A simple diagram of a voluntary and/ or involuntary thermoregulation tracing may look as follows:
Activity –> Increased core temperature –> anterior hypothalamus senses –> increased sweat rate –> evaporation (may vary depending on climate conditions) –> heat loss
How does this affect athletic performance?
Surprisingly, as little as a 2% decrease in hydration has been shown to hinder performance. This small amount can increase fatigue, increase core temperature, disrupt neuromuscular control, and ultimately directly lead to injuries. Hydrating with water throughout the day is key, but in order to replenish electrolytes lost during practice and competition a sports drink may be necessary. Although each company will claim theirs reigns supreme to other competitors’, most sports drinks will aid in hydration as well as glycogen replenishment in order to assist with performance. They also require ingesting fluids four hours prior to the intended event as absorption is key.
Below are some general guidelines that follow the RDI’s for health as well as safety. It must also be noted that the pre-exercise meal should be high in carbohydrates, moderate in protein, low in fat, adequate in energy, and accompanied by fluid.