When it comes to the simplest, cheapest, and most abundant form of liquid refreshment in the world, there seems to be a lot of confusion. Some of the most common questions include “Why do I need to drink water?”, “Coffee and beer contain water: does that count?”, and “How much should I drink?”
Because of this, it seemed like an opportune time to touch on some of the mechanisms involved.
Fresh water is the second most essential substance in the maintenance of the human body (the first being breathable air). The body is only able to survive without water for about 72 hours. In comparison, the average human being can live for up to 30 days without food. This reveals that water is not just an essential part of the human diet, but is actually necessary in order for the organs and systems of the body to maintain life. If a person had all of the water in their body removed, it would make up about seventy-five percent of the total mass of the body. It’s present in the blood, the organs, even the cells themselves, and it serves as the vehicle for almost every function of the body.
The reason that fresh water must continually be ingested is because the body is not a static or closed system. Every action and function of the body makes use of water in some degree or another, and most of them end up consuming at least some of the moisture in our body. Water is lost through respiration, perspiration, and elimination primarily, and that loss is almost always unavoidable (it can be mitigated somewhat, but the reality is that water is always being lost, so it must always be replaced.) Without adequate amounts of water in the body, several things begin to happen: the mucus membranes begin to dry out, leading to an increased vulnerability to infection; the blood doesn’t flow as smoothly, increasing the workload on the heart which raises blood pressure; the tissues of the body begin to dehydrate, affecting the organs and other tissues of the body, making them less efficient and therefore increasing the amount of energy needed to maintain proper body function; and of course, elimination – without adequate water in the body, the things that body is trying to get rid of end up getting reabsorbed into the body, making the internal ecosystem more toxic. That last effect of dehydration is why it’s so important to drink water after any kind of exercise or body work. All the metabolic waste products that are produced by or are eliminated from the muscles and tissues during the activity are loose in the blood stream afterwards and, if the person isn’t adequately hydrated, those substances will be reabsorbed by the body, which undoes a lot of the benefit of the work, and increases the post-activity soreness and discomfort.
That leads into why water, and only water, will do. When a person drinks juice, coffee, beer, cola, etc., he or she is already drinking a mixture of water and whatever else is dissolved in it. For the body, this means that it then has to separate out the water from whatever else is the water is mixed with. So while it can be hydrating, it also means that the actual amount of water consumed needs to be adjusted by the ingredients of that particular beverage. For example, in both caffeinated and alcoholic beverages, the water intake through the beverage alone is often insufficient because both of those types of drinks act as powerful diuretics, so the increase in elimination often leaves the body more dehydrated than it would be if nothing was consumed. Fruit juices and colas are another case where the ingredients in the drink actually leave the body needing more water, as it’s required to flush out the sugars that they contain. Even carbonated water products often contain high levels of sodium which marginalizes their ability to serve as adequate hydration sources. Over time, the increased concentration of the sugars, sodium, and other water-soluble substances will lead to increased damage to the body as their greater concentration places strain on both the organs where they will gather, as well as increased irritation to the arteries and veins as the blood containing it travels through the body.
The only way to avoid this is to keep hydration levels relatively constant, but how much water is the right amount? To put it simply, most people do not drink enough water. The standard recommendation is eight 8 ounce glasses of water a day (or 64 ounces total) for the average adult. However, for every cup of coffee, every glass of alcohol, every salty snack, another glass of water should be added to that intake. In order to attain a more stable level of hydration, an individual should shoot for about half of his or her body weight (in pounds) in ounces per day. For example: a man who weighs 220 lbs. should try to consume 110 oz. of water per day. Aiming for this higher amount of intake will ensure that the body will not be adversely affected by that extra cup of coffee or that particularly sweaty workout. It should be mentioned that drinking more than that amount does raise the small risk of overhydration, where the body becomes so infused with water that the blood becomes too thinned out to provide adequate nourishment for the body. The chances of this happening, however, are relatively slim, and often only occur when someone drinks several times their normal intake of water in a very short period of time.
So what are the practical effects of proper hydration? Basically, a lot of the more chronic problems that affect otherwise healthy individuals can be linked to chronic dehydration in combination with other, normal body functions. An example of this is histamine. This compound exists normally in the body and is part of the immune response. If the person is dehydrated, the level of histamine in the bloodstream becomes concentrated which then leads to increased allergic responses. Another example is the hangover. If a person drinks to excess without drinking water to compensate, the next day the mucus membranes of the mouth, nose, and gut are often dried out, leading to increased pressure in the head and intestinal discomfort (which then appear as headaches and nausea). Joint and muscle pain can also be relieved by increasing water intake as the waste products they normally produce aren’t allowed to gather in the tissues that created them.
Here’s an analogy to close out this discussion – imagine the body is a river. Inside that river are numerous plants, animals, and insects that are part of that particular ecosystem. Now imagine the water in the river has been replaced with cold coffee. Some of the organisms would be able to adapt to it, but over the long run, that river would eventually become lifeless as the balance that is meant to exist becomes replaced. It would still be wet, and it would still technically be a river, but the richness and health of the waterway would be wiped away. The same thing happens to the body, and while it might take longer to notice the changes, eventually the natural balance of the body would be equally damaged.