Hydration is more than drinking water

Not everyone takes the time to stop and think about the how’s and why’s of hydration, understanding how important it is and how to best optimize hydration is a worth the effort. Proper hydration, especially in athletics is another element you can turn into a superpower.

Hydration is essential to maintaining an ideal body temperature, especially during exercise. Sweating is water moving out of your blood onto your skin to be evaporated thereby cooling you down (evaporative cooling). The more you sweat, the more water is removed from your blood causing a drop in blood volume. To counter this, your body pulls water from other areas, muscles or tissues, to try and maintain a normal blood volume.

If you fall behind in your hydration, there won’t be enough water in your body to continue sweating and your blood gets thicker making your heart work harder. This causes an increase in your heart rate, a drop in power and a rise in your body temperature. All those changes translate into fatigue and a crumbling performance despite your best effort.

The inability to manage core body temperature due to dehydration can be life-threatening when exercising or racing in hot climates. It can also sneak up on you if you’re not paying attention or acclimated to that environment. There are many factors that influence thirst, relying on feeling thirsty to remind you to drink is not reliable, especially with more intense exercise.

Hydration is not as simple as just drinking water. What you drink is crucial.   It’s important to note that plain water is not hydrating. That’s not a typo - plain water is not hydrating.

To truly hydrate, we need the liquid we drink to be absorbed out of the gut and into your blood or tissue. The movement of water from your gut into your blood has to do with osmolality and fluid co-transporters.

Osmolality, in basic terms is the movement of water from a low concentration to a high concentration area to even them out. Your body is trying to create balance, in this case it’s trying to keep all fluids evenly concentrated and will move water around to achieve that. What makes your drink concentrated is the amount of sugar or salt in it.

If your drink is less concentrated (has a lower osmolality) than your blood, that fluid will move out of your gut and into your blood. Conversely, if you drink a very concentrated beverage, fluid will move out of your blood or tissues and into your gut to try and dilute it. This is dehydrating and creates GI distress as a bunch of liquid will now be sloshing around in your stomach.

The second aspect of hydration is co-transporters. Water needs glucose and sodium to get across your intestines and enter your blood. Potassium helps too. Its why sports drinks contain sugar and sodium, they’re necessary for optimal hydration. The problem is most sport drinks contain too much sugar and/or salt to be efficiently absorbed.

There’s no one perfect solution for everyone, you will want to play around with various concentrations to determine what works best for you and this may change depending on ambient temperature and hormonal state. Dr. Stacey Sims, PhD., the author of Next Level and Roar recommends starting with 7-9 grams of sugars, 180-225 milligrams of sodium and 60-75 milligrams of potassium per 8 oz of water.

Note that sodium and table salt are not the same thing. Salt – table or sea salt contain sodium and other minerals. A half teaspoon of table salt contains approximately 1150 mg of sodium. You may want to use sea salt to add in some potassium as table salt may not contain a notable amount.

You want a mixture of sugar sources in your sports drink to optimize absorption, ideally glucose and sucrose. Too much of one sugar can overwhelm the specific receptors and slow hydration. Maltodextrin, fructose, and stevia are common sugars used in sports beverages but can be irritating to many people’s GI tract. Again, take the time to figure out what works for you.

One way that hydration strategies can be sabotaged is by trying to get extra calories from your fluids. When you bump up the carbohydrates in your drink you risk raising the concentration to where it’s not readily absorbed. Try to keep your food (and therefore, fuel) separate from your fluids. An exception to this is in ultra-endurance events where it can be challenging later in the race to take in any food. Practice your strategies to know when you might want to make this transition and how to maintain hydration.

I will always recommend avoiding artificial sugars, food colorings and preservatives when possible. These are inflammatory to most and depending upon your genetics may be creating an excessive inflammatory response and undue stress in the body that’s completely avoidable.

Other factors that can affect hydration that you might want to consider are age and hormones.

As we mature our thirst sensation decrease. We may not feel thirsty until we’re severely dehydrated. This is true for men and women and tends to be gradual. Create a hydration routine regardless of feeling thirsty or not.

Hormones affect your hydration as estrogen and progesterone influence how your blood vessels dilate or constrict, body temperature and sodium loss. In the high hormone phase (right before your period) your body temp increases making it more important to offload heat as your baseline is higher.

Your thirst cues are also dampened as high hormones lower the threshold that triggers a response to a drop in blood volume. Meaning, you will lose a lot more water (be more dehydrated) in a high hormone phase before you feel thirsty or your body makes adjustments to retain more water.  

The amount of sodium in your sweat changes with your hormones. You not only sweat more in a high hormone phase, but your sweat contains more sodium compared to a low hormone phase. This is because progesterone competes with aldosterone – a steroid hormone that encourages sodium retention. High progesterone leads to less aldosterone, this results in more sodium being excreted or lost in sweat and urine.

Now that you understand that water needs sugar, salt, and potassium to get across your intestinal wall, that the concentration of your drink will affect its absorbability, and age and hormones change your thirst cues and potential sodium needs, you have the information necessary to begin the trial and error of dialing in your hydration strategies.

Getting specific with your body is a true superpower, hydration tactics are one more area that you can refine to further your pursuits.

Keeping you in pursuit,

Dr. Marsha✨