Active Recovery & Hydration – What Happens in Dehydration?
It’s a well-known fact that the human body is 80% water. The body loves water. However, unlike camels in the dessert, human beings are not very good at conserving it. In fact, we lose water quite easily. The quickest way to restore hydration is via intravenous administration. This is why if you go to the Emergency Room when you are throwing up or have diarrhea, you are given intravenous fluids containing water and salt (saline). After a workout or race, the fastest way to restore your body’s fluid status is to get IV fluids. The fluid is even better when antioxidants and vitamins are added to it! Read more about Vitamin Infusions for Active Recovery.
What happens with excessive water loss (dehydration)?
Initially, your heart is not able to pump out as much blood since your total blood volume is decreased by the lack of water available. The heart is a pump, and it can only pump what it receives. If it receives less blood, it pumps less blood. When blood flow decreases, you develop symptoms of severe fatigue and thirst. As the dehydration progresses, you will STOP sweating. Lack of sweating when exercising (or working) is a very ominous and dangerous sign. Seek help immediately!
As dehydration progresses, the body clamps down blood flow to the kidneys in order to stop losing water as urine. The natural breakdown products of muscle tissue begin accumulating in your bloodstream. These levels are measured by a laboratory in order to determine the severity of dehydration (BUN and Creatinine).
As dehydration progresses further, the body begins shunting blood away from the skin, muscles, bones, and GI tract in order to provide blood flow to the vital organs (heart, lungs, liver, and brain). As your muscles starve for nutrients carried by the bloodstream, they begin breaking down. During cellular death, they release a protein called CPK that can be measured in your blood stream to determine the extent of muscle damage.
Eventually, your heart will not be able to pump enough blood to keep cellular function alive. Your suffocating tissues create lactic acid without oxygen. The lactic acid turns your blood acidic. By this point, you have most likely lost consciousness and are overheating without the ability to sweat. Your temperature is rising above 104F. Treatment is emergent as you will die without life-saving intravenous fluids. Once intravenous fluids are given, your body returns to life, re-establishing its normal balance or homeostasis.
Sensible Water Loss:
Most people realize when they’re losing water: sweating, urinating, diarrhea, vomiting, drooling, runny nose, or bleeding.
Insensible Water Loss:
There’s an additional element of water loss that we refer to in medicine called “Insensible Water Loss.” We insensibly lose water through our respiratory tract and skin.
Respiratory Tract Water Loss:
This is the water required to hydrate the air we breathe. Every animal’s lungs on the planet require humidified air. With every breath, we infuse water into it to the desired humidity. Many animals reabsorb the water as they exhale, but humans do not. We exhale the humidity. The water that we add to the air to breathe is lost.
Skin Water Loss:
Since most humans do not have fur to cover our outer skin, we constantly leak water into our environment. This water is immediately dehydrated. The humidity in the air determines the rate of dehydration. This is different than sweat since it is does not contain electrolytes, and it is not intentional.
Humidity plays an important role in both sensible and insensible water loss. It is important to pay attention to the environment that you are working in. If you are in high humidity working or exercising outdoors, you will have a great gauge of how much water you’re losing based on the buckets of sweat that are accumulating. However, in dry weather, you will not see sweat accumulating yet you will be losing water at a faster pace!
Inappropriate Fluids for Rehydration
Caffeine is a Diuretic:
I frequently see patients in the ER because they have been working in the dry air, drinking Coca-cola, tea, and coffee for hydration. Although all of these liquids are majority water, they contain high amounts of caffeine, which acts as a natural diuretic. Your body is trying to conserve water, but the caffeine is forcing the body to urinate out more than it should. When you are in the heat, you must be able to drink (and keep) more water than you are urinating.
Endurance athletes must take note of the products that contain caffeine in order to not fall behind on their prolonged workouts. Many gels, bars, and drinks contain caffeine to give you a boost of energy. Be mindful of the amount of caffeine you’re consuming, especially if you’re drinking a pre-game caffeinated beverage!
Diabetes Causes Excess Water Loss:
If you are a diabetic, you also have the potential for losing more water. When your blood sugar gets too high, your kidneys cannot reabsorb it fast enough. Once your blood sugar goes over this threshold, it acts as a natural diuretic. Just like caffeine mentioned above, you must be able to absorb more water than you are losing.