By Mike Compton
In their relentless pursuit of a competitive edge, professional football players try to optimize every variable. Yet while this exercise or that supplement might provide a marginal gain, it’s nailing the basics that will yield the greatest results on and off the field. It’s arguable that nothing is more crucial than staying hydrated before and during practices and games and rehydrating afterward.
In this article, we’ll look at the effects of dehydration, examine some of the challenges Footballers and NFL players face, and see how technology is helping teams safeguard their players’ wellbeing.
The Physical and Cognitive Impact of Dehydration
Between 50 and 60 percent of your body is water, and it plays a part in every major function. Whether it’s cell creation, temperature regulation, or digestion, adequate hydration is necessary to help remain in homeostasis and, at a fundamental level, to keep you alive.
Now let’s look at what happens from a mental and physical perspective when an athlete becomes dehydrated.
A review conducted by researchers from the University of North Carolina and Tufts University summarized the effects of two studies in which participants experienced 2.8 percent dehydration from either heat stress or running on a treadmill. In both cases, the authors noted that, “performance was impaired on tasks examining visual perception, short-term memory, and psychomotor ability.”i
The researchers also remarked that dehydration can cause mood disruption and impair depth perception and visuomotor tracking. This demonstrates that the body’s command center – the brain – is negatively affected when hydration levels dip below a certain threshold.
When it comes to hydration status, we can’t separate the brain from the body, as the former controls the latter. In other words, when an athlete becomes dehydrated, their cognitive function declines, which in turn impacts the signals sent to the musculoskeletal system, affecting how it responds.
For example, a study published in the Journal of Strength & Conditioning found that golfers who were mildly dehydrated by 1 to 3 percent were less accurate and misjudged their shots by a greater margin, leading the authors to conclude that such fluid loss “significantly impairs cognitive-motor task performance.”ii
If such effects manifest themselves in a lower intensity sport like golf, it’s easy to envisage how much more pronounced dehydration can be for football players who must perform while wearing tight-fitting, padded uniforms and heat-retaining helmets.
Compromises in motor function resulting from dehydration acting upon the brain and nervous system are further exacerbated by the detrimental effects of dehydration on the tissues themselves. This is hardly surprising, given that water comprises around 70 percent of muscle, makes up most of the synovial fluid in joints, and is essential for blood flow around the body.
If a football player becomes dehydrated or doesn’t rehydrate properly during practice or a game, their performance will start to suffer. A 2015 study concluded that 3 percent dehydration reduced repeat sprint ability, while another team of exercise scientists found that lower and upper body anaerobic muscular power output is compromised when athletes’ body water levels dipped.iii
To date, there hasn’t been a definitive study to suggest that moderate or severe levels of dehydration lead to soft-tissue injuries, but as compromised hydration causes depressed neuromuscular activation, reduced cardiovascular function, increased perceived exertion, and impairments in motor performance, it’s reasonable to conclude that the incidence of injury might increase when football players become dehydrated.
Recognizing the Dangers of Overheating
The true dangers of football teams training in hot and humid conditions often fail to resonate until tragedy strikes. The sad stories of Super Bowl champion Mitch Petrus and Pro Bowl lineman Korey Stringer show the relationship between dehydration and potentially life-threatening heat stroke. One of the mechanisms that body water helps modulate is thermoregulation. Once an athlete’s core temperature reaches a certain point, they are unable to cool back down through sweat loss, and a problem can quickly escalate into a crisis.
The increasing prevalence of such situations illustrates the need for coaches to closely monitor practice conditions and make the necessary adjustments to keep their players safe. This will arguably be even more important during the upcoming NFL offseason, when COVID-19- related protocols might necessitate players training more outdoors.
There are several ways for football teams to safeguard their athletes from heat-related dehydration.
First, a team can enter weather details into an athlete management system like Smartabase and compare this to athlete exertion and recovery scores to see how heat and humidity impact player performance and recovery. The ability to map trends over time will then enable performance staff to analyze the composition of future sessions and make the necessary adjustments to intensity, density, and overall volume to reduce the physiological load on the team.
Such a data-driven insight can be combined with common sense measures like moving practice earlier or later when the temperature is lower or relocating to an indoor facility on a particularly hot or humid day.
Using Data-Driven Insights to Rehydrate
Preemptive hydration is a proven way for athletes to proactively mitigate the effects of fluid loss in practice and games. This can start with drinking a large glass of water first thing in the morning and continue with players drinking from a water bottle with each meal and snack. They can also be encouraged to eat water-rich fruits and vegetables like celery and watermelon.
To ensure they keep their fluid levels topped up, it’s also important that football players drink enough during practice. For events lasting less than an hour, water drinking to thirst should be adequate, although team-mandated water breaks during hot and humid sessions are a sensible precaution. Longer and more intense sessions might require coaches and performance staff to mandate more frequent prescribed drinking intervals and to supplement water with electrolytes and carbohydrates.
No matter how much water or so-called “sports drinks” a football player consumes before or during a practice or game, they’ll also need to pay close attention to rehydrating afterward, as fluid use and loss often outstrip replenishment. The main purpose of rehydrating is not only to replenish those fluids and electrolytes lost in sweat, but also to help establish fluid balance back within the system, according to a 2013 study led by Brendon P. McDermott.iv
One surefire way to ensure that each athlete rehydrates adequately is to record weigh-in and weigh-out data before and after individual and team activities. Every player’s sweat loss rate and fluid usage is different, so analyzing the amount of weight lost during a session will help determine their individual rehydration needs.
If you streamline the process utilizing a human performance management system with an app like the Smartabase Kiosk to collect the weigh-in and weigh-out data then you can automate instant feedback for each individual and advise them on how much to drink to rehydrate. They can also record the color of their urine, which is a solid indicator of hydration status (as seen in the dashboard above).
This can be paired with more subjective measures, such as simply asking each athlete to enter how thirsty they feel after practice or a game on a scale of 1 to 10 (which if entered into a system like Smartabase could also be normalized to the individual for more accurate data). A certain score could automatically notify the team nutritionist so that they can prepare a suitable drink, shake, and/or meal for the player and present it to them before they leave the team facility.
This way, the performance staff can focus their limited time on the team members who need the most help, and then follow up with more hydration education as necessary. Such close collaboration between athletes and staff based on a combination of quantitative and qualitative evaluation will enable players to perform well and stay safe.
For more information on tracking Athlete Hydration and Wellness using the Smartabase Athlete Management System and Smartabase Kiosk app you can contact the Fusion Sport team here.
About the Author
Mike Compton is a Principal Sport Science Consultant for Fusion Sport USA. As a former Division 1 College Basketball Strength Coach Mike has a strong knowledge of collegiate sport and a passion for applied data analytics for performance optimization.
References and resources:
 Barry M. Popkin, Kristen E. D’Anci, and Irwin H. Rosenberg, “Water, Hydration and Health,” Nutrition Reviews, August 2010, available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/.
 Mark F. Smith, Alex J. Newell and Mistrelle R. Baker, “Effect of Acute Mild Dehydration on Cognitive-Motor Performance in Golf,” Journal of Strength and Conditioning Research, November 2012, available online at https://pubmed.ncbi.nlm.nih.gov/22190159/.
 Jon-Kyle Davis et al, “Influence of Dehydration on Intermittent Sprint Performance,” Journal of Strength and Conditioning Research, September 2015, available online at https://pubmed.ncbi.nlm.nih.gov/25774626/.
 Brendon P. McDermott et al, “The Influence of Rehydration Mode after Exercise Dehydration on Cardiovascular Function,” Journal of Strength and Conditioning Research, August 2013, available online at https://pubmed.ncbi.nlm.nih.gov/23615479/.