The Hydration Equation

Nutrition, Pain

To Hydrate or Not to Hydrate?


So, I need 8 glasses of water at 8 ounces apiece and I am good, right?  Well, what if you are a coffee drinker?  What if you are an endurance athlete?  Is it different for a weight lifter?

For athletes and people on a low sodium diet, they can complain of cramps not from lack of hydration, but of hyponatremia or lack of sodium.  Muscles contract and relax using a system of gradients.  On one side is sodium and the other side is potassium. If your sodium level is depleted, the muscle will contract and spasm the same as you would with dehydration.

The Caffeine Myth:

In 1928 a study was published that showed caffeine was a diuretic.  Since, the prevailing advice has been to replace your cup of coffee or tea with a cup of water to offset the effects.  However, a study in 2014 showed that this was not accurate and that although caffeine is indeed a diuretic, 1-2 cups of coffee is equivalent to your water intake.

“Our research aimed to establish if regular coffee consumption, under normal living conditions, is detrimental to the drinker’s hydration status,” lead author Sophie Killer, a doctoral researcher, said in a statement. The study was published online today in the journal PLOS ONE.

Killer and her colleagues enrolled 50 men, all moderate coffee drinkers who didn’t take diuretics or caffeine-containing medication. Women weren’t included in the study because menstrual cycles may cause fluid balance fluctuations. In the study’s first phase, investigators randomly assigned the men to drink 4 cups of black coffee or an equal amount of water daily for 3 consecutive days. After a 10-day “wash-out” period, the groups switched. Coffee drinkers changed to water and vice versa.

The investigators analyzed hydration status with several established measures—body mass, total body water, and blood and urine tests. They found the hydration effects of coffee or water did not differ significantly. The study participants lost a small but significant amount of body mass each day during both study phases, 0.2%. Several factors may explain the body mass loss, the investigators wrote. One possibility is that the men simply didn’t drink enough fluids during the study. Even so, the men weren’t near the clinical dehydration level of 1% to 3% body mass loss, the investigators noted.

“Consumption of a moderate intake of coffee, 4 cups per day, in regular coffee-drinking males caused no significant difference across a wide range of hydration indicators compared to the consumption of equal amounts of water,” Killer said.

For athletes:

Proper hydration during training or competition will enhance performance, avoid ensuing thermal stress, maintain plasma volume, delay fatigue, and prevent injuries associated with dehydration and sweat loss. In contrast, hyperhydration or overdrinking before, during, and after endurance events may cause Na(+) depletion and may lead to hyponatremia. It is imperative that endurance athletes replace sweat loss via fluid intake containing about 4% to 8% of carbohydrate solution and electrolytes during training or competition. It is recommended that athletes drink about 500 mL of fluid solution 1 to 2 h before an event and continue to consume cool or cold drinks in regular intervals to replace fluid loss due to sweat. For intense prolonged exercise lasting longer than 1 h, athletes should consume between 30 and 60 g/h and drink between 600 and 1200 mL/h of a solution containing carbohydrate and Na(+) (0.5 to 0.7 g/L of fluid). Maintaining proper hydration before, during, and after training and competition will help reduce fluid loss, maintain performance, lower submaximal exercise heart rate, maintain plasma volume, and reduce heat stress, heat exhaustion, and possibly heat stroke.

The big takeaway from this study is that if you are an endurance athlete or your activity is higher level you could be flushing a much needed electrolyte, in this case Sodium out of your system.  General advice (always check with your MD for individual advice) is to drink regular water with food that has a little salt, otherwise include a little sodium into your water for regular consumption.  Trust in Kelly Starrett.



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