How Much Water Do I Need to Consume?

You may have heard that you are supposed to drink 8 glasses of water a day, is this true? Is it the same for everyone? In short, the answer is no; many factors influence the amount of water an individual needs to consume such as age, body size, health status, physical activity, and environmental factors such as heat and humidity.

Based on this, how can I know how much I need to drink? The simplest advice is to look at the colour of your urine; if it’s pale yellow or clear, you are sufficiently hydrated, but if it’s dark in colour, you may need to sip more fluids.

All liquids will help you stay hydrated, even those that contain caffeine (aim to consume moderate amounts of caffeine < 400 mg/day). Foods, also help to provide us with the required fluid intake. For example, lettuce, cucumbers, peaches and pineapples all have a high percentage of water.

Consequences of a Deficiency or Excess of Water

As with all nutrients, having too much or too little water has health consequences. Excessive water intake can dilute the levels of critical electrolytes in the blood. Water intoxication is rare, however, when it does happen, it can be deadly. On the other hand, having too little water in the body is common. In fact, diarrhoea-induced dehydration is the number-one cause of early childhood death worldwide. In this section, we will discuss subtle changes in electrolytes that compromise health on a chronic basis.

High-Hydration Status: Water Intoxication/Hyponatremia

Water intoxication mainly affects athletes who over-hydrate. Water intoxication is extremely rare, primarily because healthy kidneys are capable of excreting up to one liter of excess water per hour. Hyponatremia is problematic because the extreme dilution of critical electrolytes disrupts the sodium balance and causes water movement into the cells, which results in cell swelling, and can lead to edema in the brain or lungs, and even death. Over-hydration was unfortunately demonstrated in 2007 by Jennifer Strange, who drank six liters of water in three hours while competing in a “Hold Your Wee for a Wii” radio contest. Afterwards, she complained of a headache, vomited, and ultimately passed away.

Low-Hydration Status: Dehydration

Dehydration refers to water loss from the body without adequate replacement. It can result from either water loss or electrolyte imbalance or most commonly, both. Dehydration can be caused by prolonged physical activity with inadequate water intake, heat exposure, excessive weight loss, vomiting, diarrhea, blood loss, infectious diseases, malnutrition, electrolyte imbalances, and very high glucose levels. Physiologically, dehydration decreases blood volume. The water in cells moves into the blood to compensate for the low blood volume, and cells shrink. Signs and symptoms of dehydration include thirst, dizziness, fainting, headaches, low blood pressure, fatigue, low to no urine output, and in extreme cases, loss of consciousness and death. Signs and symptoms are usually noticeable after about 2 percent of total body water is lost.

Chronic dehydration is linked to higher incidences of some diseases. There is strong evidence that low-hydration status increases the risk of kidney stones and exercise-induced asthma. There is also some scientific evidence that chronic dehydration increases the risk of kidney disease, heart disease, and the development of hyperglycemia in people with diabetes. Older people often suffer from chronic dehydration as their thirst mechanism is no longer as sensitive as it used to be.

Heat Stroke

Heat stroke is a life-threatening condition that occurs when the body temperature is greater than 105.1°F (40.6°C). It is caused by the body’s inability to sufficiently cool itself via thermoregulatory mechanisms. Dehydration is a primary cause of heat stroke as there are not enough fluids in the body to maintain adequate sweat production, and cooling of the body is impaired. Signs and symptoms are dry skin (absence of sweating), dizziness, trouble breathing, rapid pulse, confusion, agitation, seizures, coma, and possibly death. Dehydration may be preceded by heat exhaustion, which is characterized by heavy sweating, rapid breathing, and fast pulse. The elderly, infants, and athletes are the most at risk for heat stroke.