Back to Basics: Hydration

PT Blog   •   December, 2018

“Pure water is the world’s first and foremost medicine.” – Slovakian proverb

Water is essential to life. The average adult body is composed of 55-65% water with the brain consisting of 78%. Newborn babies, which require more water during this crucial time for growth and development, are composed of 78% water. 71% of the Earth is covered with water (1), with 400 billion gallons of water used daily in the United States(2). When water shortages occur or toxins are present, the statistics are staggering: “unsafe water kills 200 children every hour” (3) and “80% of illness in the developing world is water related.” (4) Water regulates the Earth’s temperature, grows our food, and powers our homes. Water is important and its value cannot be overstated. Despite its necessity and availability, research suggests that up to “75% of people in the United States are functioning in a chronic state of dehydration (5).”

Benefits of Proper Hydration
1. Prevention of chronic disease:

  • A study in 2005 in the journal Nutrition Review stated “Good hydration… reduce[d] the risk of kidney stones, constipation, exercise asthma, and hyperglycemia and is associated with a reduction in UTIs, hypertension, fatal coronary heart disease, venous thromboembolism, and cerebral infarct(6).”
  • Several studies have shown that adequate hydration can reduce or alleviate headaches, with one study indicating “that water had no effect on the frequency, but did reduce the intensity and duration(7).”

2. Maximizes optimal physical performance:

  • Deleterious effects of dehydration have been observed in athletes with dehydration levels as low as 2%. These athletes will experience significantly reduced physical performance related to “reduced endurance, increased fatigue, altered thermoregulatory capability, reduced motivation, and increased perceived effort(8).”

3. Promotes weight loss

  • Drinking water helps to lose weight by increasing your sense of fullness and increasing your metabolic rate. One study showed that drinking 0.5 liter of water increased metabolism by 24-30% for 1.5 hours (9). Also, drinking 0.5 liters of water 30 minutes before a meal can boost weight loss due to increasing satiety. In another study, dieters who drank 0.5 liters of water 30 minutes prior to eating lost 44% more weight over the course of 12 weeks (10).

4. Facilitates several bodily processes (11)

  • Drinking water and establishing proper hydration lubricates the joints, cushions and protects the brain and spinal cord, aids in digestion and the elimination of bodily wastes, prevents airway restriction leading to asthma and allergies, regulates body temperature, and maintains blood pressure.

What is the daily-recommended intake?
According to the U.S. National Academies of Sciences, Engineering, and Medicine, the average recommended daily intake of water from both food and drink is ~3.7 liters or 125 ounces for men and ~2.7 liters or 91 ounces for women; however, daily intake requirements will vary depending on body size and composition, activity level, amount of perspiration, and climate among other factors.

Proper hydration is vital to living a healthy and active lifestyle, and its importance cannot be overstated. It is an easy health tip to implement that can pay forward major results, not only in the short term but long term as well. Take your health into your own hands, put down the pills / fad diet books and pour yourself a big glass of “high-quality H 2 O.”

Contributing Author Credit: W. Evan Stringfellow, PT, DPT, CSCS, Cert. DN

Edited by: Ashley Theobald, DPT

Photo by:  Samara Doole on Unsplash


  6. Manz F, Wentz A. The importance of good hydration for the prevention of chronic disease. Nutr Rev. 2005; 63 (6): S2-S5.
  7. 7. Blau JN, Kell CA, and Sperling JM. Water‐Deprivation Headache: A New Headache With Two Variants. Headache: The Journal of Head and Face Pain. 2004; 44: 79-83. doi:10.1111/j.1526-4610.2004.04014.x
  8. Popkin BM, D’Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010;68(8):439-58.
  9. Michael Boschmann, Jochen Steiniger, Uta Hille, Jens Tank, Frauke Adams, Arya M. Sharma, Susanne Klaus, Friedrich C. Luft, Jens Jordan; Water-Induced Thermogenesis. J Clin Endocrinol Metab, Volume 88, Issue 12, 1 December 2003, Pages 6015–6019
  10. Dennis EA, Dengo AL, Combe DL, Flack KD, Savla J, Davy KP, and Davy BM. Water Consumption Increases Weight Loss During a Hypocaloric Diet Intervention in Middle‐aged and Older Adults. Obesity. 2010;18: 300-307. doi:10.1038/oby.2009.235

About the Author:

Ashley Theobald, D.P.T. – Ashley was born and raised in a small town in Alabama. She attended the University of South Alabama and was an advanced undergraduate student completing her Bachelor of Science degree in pre-professional health sciences in 2012. She then graduated with her doctorate in physical therapy in 2014. During her first year of PT school she met and married her husband, Ben. They moved to Nashville, TN where she worked for 3 years in an outpatient clinic full time and at Vanderbilt Stallworth Rehabilitation Hospital PRN. She is now working for ATI Physical Therapy full-time in Greenville, SC. She has been an avid health and fitness fan playing softball growing up, tennis in high school, and completing 2 half-marathons in college. She enjoys traveling overseas and has completed 2 short-term medical mission trips for physical therapy in the Dominican Republic (2013) and Haiti (2015), with intentions of returning yearly.
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