How Dehydration kills Athletic Performance

How Dehydration kills Athletic Performance

Dehydration is a common problem for athletes, and it can have a significant impact on athletic performance. When the body is dehydrated, it doesn't have enough fluids to properly function, which can lead to a range of negative effects. These include a reduced ability to regulate core temperature, reduced max strength, and increased stress on the cardiovascular system. In severe cases, dehydration can even lead to serious health problems. In this blog post, we'll take a closer look at the effects of dehydration on athletic performance and what athletes can do to prevent it.


Exercise increases the body's core temperature due to the utilization of energy stores. The body has an optimal core temperature at which it functions best. When the body's temperature increases, sweat is the most efficient tool to counteract the rise in temperature. The body releases fluid from its pores to bring the temperature back down to its baseline. When the body is adequately hydrated, this system functions as it should and gradually decreases the elevated core temperature. However, when an athlete begins exercising while dehydrated, their sweat rate decreases, leading to an elevated core temperature and an inability to lower it efficiently. This puts athletes at risk of heat-related injury such as heat exhaustion and heat stroke. Additionally, their performance is negatively impacted as an increased core temperature increases the rate of glycogen use and acid levels within the cells, leading to muscle glycogen breakdown and lactic acid build-up, contributing to early onset fatigue and reduced ability to perform for long durations.



Muscles are responsible for moving the body and various objects, and they are designed to produce force. It is well-known that muscles are composed of approximately 75% water, making hydration a crucial factor in their optimal performance. The osmotic pressure within the muscle cells is tightly related to the potential of contractile proteins. When fluid balance is optimal, so is the osmotic pressure within the muscles, allowing them to contract to their full potential. However, when dehydrated, the osmotic pressure within the muscle cells is suboptimal, leading to decreased strength output. This has been demonstrated in studies conducted by Old Dominion University and the University of Connecticut, which found a 10% decrease in one-rep max and a 20% decrease in lower body strength, respectively, when subjects were dehydrated. Furthermore, dehydration also impacts testosterone levels, which are strongly linked to max strength and strength gain. When the body is dehydrated, cortisol levels increase, competing with testosterone for enzymatic receptors, reducing overall testosterone levels and impairing the ability to produce maximal strength and gain strength through muscle tissue synthesis.



Dehydration leads to a reduction in total blood volume and blood pressure. When dehydration reduces plasma volume, blood viscosity increases, central venous pressure decreases, and the amount of blood returning to the heart is reduced. During peak athletic intensity, these changes can decrease the amount of blood entering the heart during diastole, the phase in the cardiac cycle where the heart relaxes and fills with blood. Consequently, less blood is available to leave the heart during systole, the phase where the heart contracts, leading to a decrease in cardiac output. The subsequent reduction in cardiac output also affects the transport of vital nutrients that facilitate performance, resulting in reduced oxygen delivery to the muscles and increased buildup of carbon dioxide. As a result, an athlete's VO2 max decreases significantly. In addition to the negative effects on performance, the increased stress on the heart during exercise when dehydrated can lead to further, more dangerous, health complications.

In conclusion, dehydration is a common problem for athletes that can have significant negative effects on athletic performance. These effects include reduced ability to regulate core temperature, reduced max strength, and increased stress on the cardiovascular system. In severe cases, dehydration can even lead to serious health problems. To prevent these negative effects, athletes should make sure to stay hydrated before, during, and after exercise. This can be achieved by drinking plenty of water and electrolyte-rich fluids, monitoring their fluid intake, and listening to their body's thirst cues. By taking these steps, athletes can help ensure that they are properly hydrated and able to perform at their best.

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