I hate drinking water. It just seems so inefficient unless I can actually see the sweat dripping off my body and thus a need to replace fluid.
It was easy when it is hot and humid, watching water leave every pore of your body. But in milder weather or even less intense activities, why would you even bother hydrating if you are not sweating?
We talked about central drive before, as it is the primary factor behind fatigue (see Sparta Point). Central drive is a reduction in the nervous system’s command to working muscles, resulting in a decline in the force output. Basically, when your brain gets tired, you do not want to continue exercising. But since your brain is 70% water, not providing water will affect every bodily function, whether it is a sport or sleeping through the night.
Most hydration studies look at endurance performance, but since these activities (i.e. running for more than 30 seconds) will immediately decrease your power, we will stick to research on strength, or the ability to generate force. A 2007 study out of the Human Performance Lab at the University of Connecticut tested seven healthy males under three conditions: euhydrated (normal), hypohydrated by 2.5 percent body mass, and hypohydrated by 5 percent body mass.
The level of hydration did not affect vertical jump or 1 repetition maximum performance on squat, but water content did affect the volume of training. Even the slightly dehydrated subjects performed less repetitions for each set. The authors noticed that central activation of the nervous system seemed to have been reduced, resulting in a more rapid fatigue. Though the mechanisms are unclear, less hydration just reduces the desire to work harder.
This lower volume has long term consequences. If you want to be more involved in your sport, you will have to take more breaks in play, or if you want to pass your fitness test, you won’t be able to run as fast for as long. Higher volumes and intensities during resistance training have also been shown to increase growth hormone, which is responsible for everything good: more muscle, less fat, better skin….
Of course, proper hydration has also been discussed to optimize the ratio of cortisol to testosterone, another important anabolic hormone (see Sparta Point). The study found that the dehydrated individuals had higher levels of cortisol, a hormone that is a marker for stress, and lower levels of testosterone, a hormone responsible for much of the growth in strength and muscle size after exercise. Such detriments were greater as the level of dehydration increased.
Our recommendation is still the same: drink at least half your body weight in ounces. Seems like crucial advice since your training revolves around your nervous system and brain, an organ that is 70% water.