As we discussed last time, Air and breathing, are a fundamental ingredient of life and thus of health. Indeed, without air, no one can live for more than a few minutes. Water is also essential. In the case of water, perhaps, we can go a little longer, a few days or week at most before dehydration catches up to us.
Water makes up ~70% of the earth’s surface and ~60% of the body. (More specifically, blood is 92% water, the brain and muscles are 75% water, and bones are about 22% water.) We’ve all heard these (or similar) statistics, but what does water really do in our body and how much do we really need to drink every day?
The role of water in health:
Let us return for a moment to some basic kitchen chemistry. Oil and water don’t mix. Oil is made from fats and doesn’t like to mix with water; thus substances of this character are call “hydrophobic.” Water, salts and other so called “aqueous” or “hydrophilic” substances freely mix or dissolve in water. (Soap is an interesting digression here, because molecularly, it possesses both a hydrophobic piece and a hydrophilic piece, which enables it to dissolve in either substance and also to allow for the mixing of oil and water.) So in the body, we have hydrophobic elements; these include things like cell membranes, nerves, fat tissue, hormones and certain proteins. These hydrophobic cell membranes encircle the aqueous (or hydrophilic) environment of the interior of the cell, the cytosol.
Dissolved in this aqueous world are salts or ions (like sodium, calcium, potassium, magnesium), sugars as well as many other proteins and signaling molecules. These ions, often lumped together to be called “electrolytes,” are kept at specific concentrations both inside and outside of the cell with complex and exquisite molecular pumps. The flow and motion of these ions is essential for life. These movements create cellular energy (called ATP), transmit nervous system impulses (called action potentials), and ultimately influence whether the cell lives or dies.
All of which is to say, there is a myriad of vital and essential biochemical reactions that occur in the delicate aqueous environment of the body. If water balance is disrupted, concentrations of ions or proteins can change and derangements in cellular functioning can occur.
Let us not forget the kidney in out discussion of water. Our kidneys are amazing. They act as filters for the blood. They excrete water soluble toxins and metabolic wastes. They also regulate salt and water balance. Every minute 1.2 liters of blood passes through the kidney. That works out to be over 1700 liters everyday!
If dehydrated, symptoms including: easy fatigability, thirst, muscle cramps, muscle weakness and postural dizziness. More severe fluid loss can lead to abdominal pain, chest pain, or lethargy, confusion and even death.
In less severe circumstances, chronic low level dehydration can lead to constipation, dry skin, increased susceptibility to infections, and fatigue. Additionally, symptoms indicative of poor processing of toxins and wastes (things like rashes, allergies, joint pain, inflammation) can manifest. The kidney is one of the major organs of elimination. If we don’t provide them enough water to dilute and excrete wastes, over time those wastes can build up and cause symptoms.
It is also fair to mention, that CLEAN fresh water is important. With water borne illnesses, environmental toxins, pesticide and pharmaceutical residues, heavy metal contamination and intentional chloridation or fluoridation of water, it is sometimes hard to know what to do. This topic deserves its own in depth discussion, but in short, we are very lucky in the US to have a water supply that (almost always) does not expose us to overtly harmful substances. However, for some sensitive people, they may need more rigorous standards for their water. In these cases, there are many good quality water filters that can help to ensure removal of harmful contaminates.
How much do we need?
Since water need is dependent on many factors (including age, gender, activity level, climate) it is hard to put out a hard number. A good rule of thumb is to drink half your body weight in ounces of water every day.
Thus a 150 pound woman would need to drink 75 ounces of water everyday.
A good practice is to try to drink a large glass (perhaps ~16 oz) first thing in the morning. It gets you well on your way to meeting you water target, and additionally, it jumpstarts the detoxification of all the wastes accumulated during sleep.
Next time, we will explore rest and sleep and their roles in providing us a stable foundation for health and wellbeing.