Who's Thirsty? August 8, 2016 17:58

The ins and outs of proper hydration

Keeping hydrated throughout the hot summer months is critical to enjoying your activities and improving your performance. For endurance sports it can be the difference between finishing strong and a DNF.

As little as a 2% body weight loss during activity can set off a chain reaction in your body that wreaks havoc on your system. The more dehydrated you get, the worse the symptoms can be. If you lose 5% of your body weight, you can expect a headache, fatigue, irritability, and that "spaced-out" feeling.

Proper hydration during athletic activity allows for efficient delivery of vital fluids and electrolytes that prevent muscle cramping, exhaustion, heat stroke, and a full-on medical emergency. To check your hydration, remember the simple “pee test”! Your urine should be very light yellow. Dark yellow can mean you are dehydrated and dark yellow/brown means you are severely dehydrated and need medical attention. 

Tips to keep hydrated:

  • Drink when slightly thirty!
  • Drink Early!
  • Drink at regular intervals!
  • Know your sweat rate!

 Sweat Rate = (A + B) ÷ C, where 

A = Pre-exercise body weight – Post-exercise body weight, recorded in ounces. (1 lb. = 16 oz.)
B = Fluid Consumed During Exercise, recorded in ounces. (1 cup = 8 oz; 1 gulp = about 1 oz)
C = Exercise Duration, recorded in hours. (40 min = .66 hr)

Like nutrition the right balance of hydration is unique to the individual. It is important to note that individual sweat rates are highly variable and sweat rates should be calculated on like activities and efforts. Understanding your sweat rate is critical so you have an accurate perception of your fluid loss and therefore how much you need to drink to replenish your body’s stores.

Hydration needs to be a constant effort because it becomes impossible to replenish the amount of fluid you lose during efforts greater than 90 minutes. At this time, your sweat rate approaches 3 liters per hour and your body can only process about one liter per hour. At this rate the best you can hope for is to postpone the fatigue. The expected dehydration after longer efforts will balance out over a short period with fluids and food.

Don’t underestimate the importance of sodium and electrolytes in hydrating. Consume sports drinks to replenish those vital minerals. If you only drink water before an event, you actually deplete the sodium in your system and are taking a step backwards. Absorption of fluids, is maximized by osmolality of the fluids, which is determined by the temperature in which you are exercising. If it is hot, your sports drink should be more diluted so it will be absorbed into your system. If it is cold, your drink can have a higher concentration of electrolytes (less diluted) and it will still be absorbed.

 As we finish off the summer in some of the hottest temperatures of the year, don’t downplay the importance of hydration in your activity. Drink up!