Why Hydration Strategies Fail (And How to Stay Hydrated)

A small 2% loss of body weight from dehydration can lead to a decrease in cognitive performance. Many people fail to drink enough water because they rely primarily on thirst sensation. Today we're talking about the importance of hydration. You also need to know how to tell when you need to take a drink, hydration strategies, and prevention/treatment of dehydration.

Why hydrate?

There are several reasons you need to stay hydrated during activity.

• First, transportation! The average adult male is made up of 60% water, 55% for females. Water in the body helps transport nutrients and remove waste. Blood is 75% water, and nutrients like carbohydrates, lipids, and proteins are transported to different areas of the body through the blood. Waste products are excreted and water helps in this process. Additionally, water helps protect the body against foreign invaders by creating mucus, which is 90% water. Mucus helps rid the body of pathogens and nasal irritants.

• Second, thermoregulation: the balance of heat gain and loss in the body. Water works to store heat in the body and keep core temperature constant at 98.6F. When the body gets too hot, the hypothalamus in the brain (control center for temperature) sends a message to muscles to dilate. Sweat is the body releasing heat in an attempt to cool off (much like opening the windows on a sunny day). When it’s cold out the hypothalamus sends the message to the muscles to constrict in order to maintain heat.

• Third, water balance. Every day you lose water, sometimes without even thinking about it. When you exhale or sweat, you lose water. When you urinate you lose water. In order to stay balanced, match water output with water input. Too much output and not enough input leads to dehydration. Dehydration is often the gateway to more serious problems such as muscle cramps, exertional heat exhaustion, and ultimately stroke.

How do I know when to drink?

There are several ways to measure hydration levels in the body ranging in complexity and practicality: weight, urine color, and a urine specific gravity test.

• Weight: Because weight can change depending upon the time of day, timing of meals relative to exercise, and calories burned during exercise, it’s important to compare post-exercise weight to a relative standard. You do this by the following formula: (pre-exercise weight – post exercise weight/pre exercise bodyweight x 100). A simpler less exact method is: pre weight exercise – post weight exercise. Athletes should measure themselves at least before and after exercise, and during as well when available. Weights within +-1 well hydrated, -1 -3 minimal dehydration, -3 – 5 significant, >5 serious dehydration. A >2% decrease in bodyweight indicates that athletes are dehydrated and needed more water during the event.

• Urine color: Using a urine color chart is a simple way to gauge hydration status. Higher numbers indicate darker urine. Darker urine indicated a greater degree of dehydration (1-2 well, 3-4 minimal dehydration, 5-6 significant, >6 serious). Measure this before exercise.

• Urine specific gravity: While extremely accurate, this method involves taking a sample of urine and looking at the volume of water in the urine which may be difficult to do before practice or game situations.

Hydration Strategy

There are many steps athletes can take to maintain hydration levels during activity. The National Athletic Trainer’s Association lists 18 of them, and I would like to go over 10 of those steps:

1. Establish individual hydration protocols. Hydration needs vary depending upon sweat rates, sport dynamics, environment, exercise duration, and intensity.
2. Know your sweat rate. An easy way to calculate this is to have one one hour practice session for all athletes without breaks for hydration or bathroom use. Measure athletes before exercise and after. Take your pre-exercise weight and subtract your post exercise weight and you get your sweat rate. This can vary between .5L and 2.5L for individuals.
3. Flavor liquids to preference.
4. PRE EXERCISE: consume 500-600ml (17-20oz) 2-3 hours before exercise and 200-300ml (7-10oz) 10-20 minutes before exercise.
5. DURING EXERCISE: consume 7-10oz every 10-20 minutes based on needs. Maintain less than 2% bodyweight reduction. Individual needs vary based on sweat rate, sport, and tolerance.
6. POST EXERCISE: Drink beverages containing water, carbohydrate to replenish glycogen storage, and electrolytes to speed rehydration.
7. Beverage temperature between 50-59F.
8. Use sports drinks containing CHO if exercise is more than 1 hour long or intense. 1L of 6-8% CHO drink per hour of exercise, 1g/min.
9. Recognize the signs of dehydration: thirst, irrability, discomfort followed by headache, dizziness, cramps, chills, vomit, decreased performance.
10. Have a plan in place in case of emergency dehydration situations.

Emergency planning

Because many of you will run and train in extremely hot environments, it’s important to know how to recognize, prevent, and treat exertional heat loss illnesses.

Recognize

• Muscle crams: cramps, localized pain, dehydration, thirst, sweating, fatigue, usually less than 5 minutes
• Heat syncope: brief fainting, dizziness, tunnel vision, pale/sweaty skin, decreased pulse
• Exertional heat exhaustion: excessive fatigue, fainting, collapse, hallucinations, confusion, altered mental status. Rectal temp obtained. Less than 105F core temp
• Exertional heat stroke: core body temp >105F, patient collapses, CNS dysfunction

Prevention

• Gradually acclimate to heat over 7-14 days, increase intensity and duration slowly. Most dangerous time is the pre-season workouts.
• Athletes with viral infections should not participate in practice
• Keep hydrated. Avoid 2% body loss weight, keep urine light in color.
• Have emergency plan in place, teach all coaches to recognize and prevent EHI/EHS
• Have medical care available. Athletic trainers reserve right to pull players from practice, refer to doctors if needed
• Cold water or ice tub available to immerse patient if EHI/EHS suspected
• Rectal temp clinical gold standard for obtaining core body temp for individuals with EHI
• Sleep 7 hours at night in cool environment, eat balanced diet, proper hydration. Rest times between sessions 2-3 hours allow for food
• Pre-season policy develops to deal with heat—in hot days shorten activity or reschedule
• Individuals susceptible to EHI should be identified
• Rest breaks planned, work to rest ratio matches intensity of activity, cooling zone, shade, fluid, time to take off helmet

Treatment

• Muscle cramps: rest, passive and static stretching. Ice, massage, both. Electrolyte beverage along with food for sodium replacement. Beverages containing sodium and carbs help
• Heat syncope: move to shaded a read, monitor vital signs, elevate legs, cool skin, rehydrate
• Exertional heat exhaustion: remove excess clothing, moved to shaded or cool area, use towels and ice. Legs elevated above level of heart. If no improvement, intravenous fluids and transfer to physician
• Exertional heat stroke: Lower core body temp to less than 102F within 30 min of collapse. Body cooling lowers core temp and return blood from skin to heart. Immerse in cool tub, monitor rectal temp every 5-10 minutes, cold water immersion up to neck most effective, patient removed when core body temp reaches 102, cool 1F every 3 minutes, cooled first, transported second, treatment within 30 minutes

SOURCES
Casa, D. J., Armstrong, L. E., Hillman, S. K., Montain, S. J., Reiff, R. V., Rich, B. S., ... & Stone, J. A. (2000). National Athletic Trainers' Association position statement: fluid replacement for athletes. Journal of athletic training, 35(2), 212.

Casa, D. J., DeMartini, J. K., Bergeron, M. F., Csillan, D., Eichner, E. R., Lopez, R. M., ... & Yeargin, S. W. (2015). National Athletic Trainers' Association position statement: exertional heat illnesses. Journal of athletic training, 50(9), 986-1000.

Hydration & Thermoregulation for Athletes. (2019). In Basic Foundation of Nutrition for Sports Performance (pp. 296–333).