It may surprise you to learn that 75% of Americans are Chronically Dehydrated. A survey of 3,003 Americans found that 75 percent likely had a net fluid loss, resulting in chronic dehydration [i].

Water is the most vital compound for any living organism. It constitutes up to 70% of the total body weight, depending on age, gender, and body composition. Water is the main component of all fluids in the body and involves almost in every functions of the body.

Body Composition:
Water	60%
Proteins	18%
Fats	15%
Minerals	4%
Carbohydrates	2%
Vitamins	1%

WATER LOSS

An average person with little or no exercise loses about 2200 ml (2.2 L) of water daily. For the daily water loss, see the table below [ii].

DEHYDRATION EFFECTS ON YOUR BODY [iii]

1. PHYSICAL PERFORMANCE
   • During challenging athletic events, it is not uncommon for athletes to lose 6–10% of body weight in sweat loss, thus leading to dehydration if fluids have not been replenished. However, decrements in physical performance in athletes have been observed under much lower levels of dehydration, as little as 2%.
   • Under relatively mild levels of dehydration, individuals engaging in rigorous physical activity will experience decrements in performance related to reduced endurance, increased fatigue, altered thermoregulatory capability, reduced motivation, and increased perceived effort.
2. COGNITIVE PERFORMANCE
   • Water, or its lack (dehydration), can influence cognition. Mild levels of dehydration can produce disruptions in mood and cognitive functioning.
   • As with physical functioning, mild to moderate levels of dehydration can impair performance on tasks such as short-term memory, perceptual discrimination, arithmetic ability, visuomotor tracking, and psychomotor skills.
3. DEHYDRATION AND DELIRIUM
   • Dehydration is a risk factor for delirium and for delirium presenting as dementia in the elderly and in the very ill.
   • Recent work shows that dehydration is one of several predisposing factors for confusion observed in long-term-care residents.
4. GASTROINTESTINAL FUNCTION
   • Constipation, characterized by slow gastrointestinal transit, small, hard stools, and difficulty in passing stool, has a number of causes, including medication use, inadequate fiber intake, poor diet, and illness. Inadequate fluid consumption is touted as a common culprit in constipation, and increasing fluid intake is a frequently recommended treatment.
5. KIDNEY FUNCTION
   • In addition to regulating fluid balance, the kidneys require water for the filtration of waste from the bloodstream and excretion via urine. Water excretion via the kidney removes solutes from the blood.
   • The kidney is crucial in regulating water balance and blood pressure as well as removing waste from the body.
6. HEART FUNCTION AND HEMODYNAMIC RESPONSE
   • Blood volume, blood pressure, and heart rate are closely linked. Blood volume is normally tightly regulated by matching water intake and water output.
   • In healthy individuals, slight changes in heart rate and vasoconstriction act to balance the effect of normal fluctuations in blood volume on blood pressure. Decreases in blood volume can occur, through blood loss (or blood donation), or loss of body water through sweat, as seen with exercise. Blood volume is distributed differently relative to the position of the heart, whether supine or upright, and moving from one position to the other can lead to increased heart rate, a fall in blood pressure, and, in some cases, syncope.
   • Water intake acutely reduces heart rate and increases blood pressure in both normotensive and hypertensive individuals. These effects of water intake on the pressor effect and heart rate occur within 15–20 min of drinking water and can last for up to 60 min. Water ingestion is also beneficial in preventing vasovagal reaction with syncope in blood donors at high risk for post-donation syncope.
7. HEADACHE
   • Water deprivation and dehydration can lead to the development of headache. Although this observation is largely unexplored in the medical literature, some observational studies indicate that water deprivation, in addition to impairing concentration and increasing irritability, can serve as a trigger for migraine and can also prolong migraine. In those with water deprivation-induced headache, ingestion of water provided relief from headache in most individuals within 30 min to 3 h. It is proposed that water deprivation-induced headache is the result of intracranial dehydration and total plasma volume.
8. SKIN
   • The skin contains approximately 30% water, which contributes to plumpness, elasticity, and resiliency. The overlapping cellular structure of the stratum corneum and lipid content of the skin serves as “waterproofing” for the body. Loss of water through sweat is not indiscriminate across the total surface of the skin, but is carried out by eccrine sweat glands, which are evenly distributed over most of the body surface. Skin dryness is usually associated with exposure to dry air, prolonged contact with hot water and scrubbing with soap (both strip oils from the skin), medical conditions, and medications. While more serious levels of dehydration can be reflected in reduced skin turgor, with tenting of the skin acting as a flag for dehydration, overt skin turgor in individuals with adequate hydration is not altered. Water intake, particularly in individuals with low initial water intake, can improve skin thickness and density as measured by sonogram, offsets transepidermal water loss, and can improve skin hydration. Adequate skin hydration, however, is not sufficient to prevent wrinkles or other signs of aging, which are related to genetics and to sun and environmental damage. Of more utility to individuals already consuming adequate fluids is the use of topical emollients; these will improve skin barrier function and improve the look and feel of dry skin.
9. FATIGUE
   • A pair of recent studies found that young people who were mildly dehydrated were much more likely to feel fatigued  during moderate exercise and even when sedentary. Unsurprisingly, fatigue is a common dehydration symptom, and it’s said to be the No. 1 cause of midday fatigue. [iv, v]
10. METABOLISM
    • Although the evidence is limited, your metabolism could benefit from drinking cold water. In fact, one study found that drinking cold water helped boost healthy men and women’s metabolic rate by 30 percent. The researchers concluded that the body expended more energy heating the cold water, which resulted in the boost in metabolism. [vi]

HYDRATION AND CHRONIC DISEASES

Many chronic diseases have multifactorial origins. In particular, differences in lifestyle and the impact of environment are known to be involved and constitute risk factors that are still being evaluated. Water is quantitatively the most important nutrient. In the past, scientific interest with regard to water metabolism was mainly directed toward the extremes of severe dehydration and water intoxication. There is evidence, however, that mild dehydration may also account for some morbidities. [iii]

Summary of evidence for association of hydration status with chronic diseases. [https://academic.oup.com/view-large/112300689]

Categories of evidence used in evaluating the quality of reports. [https://academic.oup.com/view-large/112300687]

WATER REQUIREMENTS

Several factors affect daily water intake. They include size of the body, activity level, diets, environmental temperature, and health conditions such as fever, diarrhea, and kidney diseases. Even though an average person loses 2.2 L of water daily, he requires only 2 L of water daily, as the body produces about 200 ml of water daily. It is called “metabolic water”, which comes from the catabolism of macronutrients and chemical reactions taken place in the body.

SIMPLE EQUATION TO CALCULATE AVERAGE DAILY WATER INTAKE

AVERAGE DAILY WATER INTAKE = 
250ml (Body Wt. in lbs. / 16) 
+ 250ml (Total mg of Caffeine / 60mg) 
+ Total lbs. Lost During Exercise (500ml)

The three sources of water are liquids, foods, and metabolic water. Milk and juices contain considerable water, but they do not count as the same volume of water. Not only do not alcoholic beverages and caffeine – containing drinks such as coffee, tea, and sodas count as water, but also they require an increase in water intake, because they act as diuretics. See the following link for water content range in selected foods.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/table/T1/?report=objectonly

WATER INTAKE BEFORE EXERCISE

In order to maintain peak athletic performance and achieve adequate recovery, it is mandatory to sustain the optimal level of hydration not only before exercise but also throughout the exercise. Dehydration causes a decline in peak athletic performance, hindering athletes to excel. In general, a simple guideline would be as follow:

• Drink at least 2 liters throughout the day.
• 2 hours before exercise: 2 glasses of water.
• 1 hour before exercise: 1 glass of water.
• 30 minutes before exercise: 1 glass of water.
• 20 minutes before exercise: 1 glass of water.
• 10 minutes before exercise: 1 glass of water.

WATER INTAKE DURING EXERCISE

In order to keep the body fully hydrated during training sessions, you should drink ½ to 1 glass of water every 10 minutes. If you are not thirty, it does not mean that you are not dehydrated. Because thirst is not a good sign of how much hydrated you are.

Practically, athletes are taught to evaluate their hydration levels by using the two following guidelines:

1. Urgent feeling to urinate during or immediately after training. If you do not have the urge to urinate during your exercise session or within few minutes after exercise, it is a good and reliable sign that you have not taken enough water during your exercise session.
2. Color of the urine. This is not as reliable as the first sign. However, it is a useful indicator to assess hydration level. The urine is usually clear like water or slightly yellow. If the color of the urine is strong yellow or orange – colored, it could be a sign of not having enough water during exercise. You should bear in mind that taking some supplements or medications could affect the color of urine. For example, vitamin B2 (riboflavin) makes the color of urine strong yellow.

There are other factors that determine the degree of dehydration during exercise, and they include intensity of exercise, temperature and humidity of exercising environment, and strength or endurance training. Endurance athletes are more prone to dehydration than strength athletes. Regardless of what the sport is, an optimal hydration is a key to athletic excellence, and dehydration can significantly impair athletic performance and even increase tendency to sports injuries.

WATER INTAKE AFTER EXERCISE

The amount of water required during early post – workout period is at least 2 glasses (500 ml) or 2 glasses of water per one pound weight lost, whichever counts higher.

If your goal is getting leaner, dropping more body fat, or losing weight, you should always wait the whole 30 minutes, giving enough time for your body to continue burning fat unless you feel dizzy or lightheaded.

If your goal is not losing weight, and you want to build more muscles and increase your size, then you should not wait, and you may proceed immediately to the next period and follow the advices over there.

CONCLUSION

Water is the most essential component to every living organism. With 75% of American’s being chronically dehydrated it is important that we stress the importance of decreasing that statistic. Chronic dehydration can cause significant impairments/ deficits and dysfunction. It is especially important to hydrate before, during and after exercise; as well as in extreme environments.

I challenge my patients to follow the above water intake recommendations for at least 2 weeks to notice the difference! You may feel the need to urinate all the time at first but your body will adapt to being properly hydrated after time. Of course, if you have any existing condition or disease that may be affected by water intake, please consult your physician prior to starting this program. To simplify things, this is the equation to follow:

REFERENCE FORMULA

AVERAGE DAILY WATER INTAKE =
250ml (Body Wt. in lbs. / 16)
+ 250ml (Total mg of Caffeine / 60mg)
+ Total lbs. Lost During Exercise (500ml)
+ Water intake before exercise (2 hours before exercise: 500ml of water, 1 hour before exercise: 250ml of water, 30 minutes before exercise: 250ml of water, 20 minutes before exercise: 250ml of water, 10 minutes before exercise: 250ml of water.
+ Water intake during exercise (125 to 250ml of water every 10 minutes of exercise)

Let us know your thoughts and your experience!

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REFERENCES

[i] Survey of 3003 Americans, Nutrition Information Center, New York Hospital-Cornell Medical Center (April 14, 1998).
[ii] Canadian Academy of Sports Nutrition (2014).
[iii] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/
[iv] Ganio, M. S., Armstrong, L. E., Et. Al (2011). Mild dehydration impairs cognitive performance and mood of men. British journal of Nutrition, 106(10), 1535-1543.
[v] Armstrong, L. E., Et. Al (2012). Mild dehydration affects mood in healthy young women. The Journal of nutrition, 142(2), 382-388.
[vi] Boschmann, M, Et. Al (2003). Water-induced thermogenesis. The Journal of Clinical Endocrinology & Metabolism, 88(12), 6015-6019.