Myths Dispelled by Tony Marchand, M.D.

General hydration:

Myths: When you search the internet, it's easy to find article supporting and debunking common saying concerning every day hydration. But here are some common myths about hydration1:

  • Common myths::
  • 2 glasses of water after waking up - helps activate internal organs
  • 1 glass of water 30 minutes before a meal - helps digestion.
  • 1 glass of water before going to bed - helps lower blood pressure and avoids stroke or heart attack
  • Water at bed time will also help prevent night time leg cramps. Your leg muscles are seeking hydration when they cramp and wake you up with a Charlie Horse.
The statement that water "activates internal organs" in the morning is misleading (our organs function quite well all on their own while we sleep, and they continue functioning after we wake up)2.

The suggestion that a glass of water "helps digestion" is nebulous (how would that be measured?) although Dr. Michael Picco disagrees and feels that drinking water during meals may actually help3 as does whfoods4.

The claim that it "helps lower blood pressure and avoids stroke or heart attack" is erroneous. Lowering salt intake or increasing sodium output through certain anti-hypertensive medications is key5. Increasing water intake may just dilute the sodium the blood sodium without affecting blood pressure. Some anti-hypertensive medications such as Beta Blockers work on the cellular level to block the affects of adrenaline and other "stress hormones" and are prescribed in addition to lower of salt intake. Changes in life style can also help lower blood pressure6.

Leg cramps can be caused by a variety of causes7:
  • Prolonged sitting, or not getting enough potassium, calcium or magnesium in your diet can be associated with leg cramps.
  • Certain medications - including diuretics, beta blockers and other blood pressure drugs.
  • Dehydration as a cause of cramping, especially in athletes, is debatable as mentioned below.
So what shall I do?
  • Try the follow:
  • Drinking water and other liquids throughout the day can keep you from becoming dehydrated. It can also help your muscles contract and relax more easily.
  • It's especially important to replenish your fluids when engaging in physical activity and to continue drinking water and other liquids after being active. But also remember to replenish your electrolytes8 to avoid hyponatremia (low blood sodium). See more below.
  • Take medications as prescribed. If you develop muscle cramping, notify your physician.
  • Watch your salt intake (our use a salt substitute) if you are hypertensive (have high blood pressure or are on medication for such).
  • Eat a balanced diet. Fruits and vegetables also contain fluids.
The one potentially true bit of information related to this item is that some studies have suggested a higher daily intake of water may reduce the risk of coronary heart disease9.

In addition For Athletes10:
  • Dehydration does not usually cause cramps: The amount of magnesium and calcium in sweat is minute compared to body stores making it unlikely to be the cause of cramping. But there is still much debate over this issue.
  • Drink early and drink often: The motto has always been "Eat before you get hungry, drink before you get thirsty". However, sports scientists now recommend drinking just enough to satisfy thirst in order to avoid hyponatremia (low blood sodium). Your body is marvelously effective at self-regulating. If you become significantly dehydrated, your thirst mechanism will kick in.
  • Don't forget electrolysis. Replacing with water alone can lead to hyponatremia (low blood sodium) resulting in headache, dizziness and even coma. A liter of sweat contains about 800 mg of sodium—half the recommended daily intake of sodium. A quart of your sweat contains 115 mg of potassium, only about 2.5 percent of the recommended daily intake of potassium.
  • Most sports drinks do not supply enough of the electrolytes you need. The American College of Sports Medicine recommends that a sports drink contain 125 to 175 mg of sodium per 8 fluid ounces and 20 to 48 mg of potassium per 8 fluid ounces10. Most sports drinks don't provide nearly enough sodium, the one electrolyte you really need to replace. If they had enough sodium they'd taste terrible. Read the ingredients on the label of your sports drinks. A another option is to carry a mixture of salted peanuts, M&Ms, small pretzels and raisin (so called "trail mix.") in the pocket of your jersey. One may choose to supplement with tablets such as endurolyte or those offered by Puritan Pride but this does not allow for supplementing on the run out of your back pocket.
  • How much fluid with electrolytes whould I drink? That depends on the level of activity, the degree one sweats, and individual tolerance11 Dehydration does not begin until one has lost 1 - 2 % of ones body weight/ Dehydration of greater than 3% of body weight further disturbs physiologic function and increases an athlete's risk of developing an exertional heat illness (ie, heat cramps, heat exhaustion, or heat stroke)12. Hydrate well before exercise. One can weigh one's self before and after exersise to get an idea of whether hydration is adequate. Again, you don't want to lose more then 1% of your body weight. The University of Connecticut study13 and American College of Sports Medicine research give more details.14
  • What about caffeinated drinks? Research has shown that caffeinated drinks are only mildly diuretic and for each cup of coffee, you probably retain more then half as fluid15,16. Alcohol, on the other hand, does act as a strong diuretic17,18.

  1. Water Weal  From by Barbara Mikkelson, July 11, 2013
  2. Does Drinking Water at Certain Times Of The Day Maximize Its Health Benefits? From Hoax Slayer - written by Brett Christensen.
  3. Nutrition and healthy eating  Michael F. Picco, M.D., Mayo Clinic
  4. Is it okay to drink water while eating or will it negatively impact my digestion?  From
  5. Your Guide to Lowering Blood   From the National Institutes of Health
  6. 10 ways to control high blood pressure without medication  From the Mayo Clinic Staff
  7. Steps to Relieve Leg Cramps   Paul Takahashi, M.D., Primary Care Internal Medicine, Mayo Clinic, Rochester, Minn., 2012
  8. Nutrition and healthy eating  From the Mayo Clinic Staff (note: page 2 on hyponatremia).
  9. Water, Other Fluids, and Fatal Coronary Heart Disease  Jacqueline Chan, Synnove F. Knutsen, Glen G. Blix, Jerry W. Lee and Gary E. Fraser, American Journal of Epidemiology, 2002
  10. ACSM Fluid Replacement Recommendations The Coca Cola Beverage Institute for Health and Wellness.
  11. How to Calculate Sweat Rate.  The Coca Cola Beverage Institute for Health and Wellness.
  12. How Much Does Dehydration Affect Performance?  From Active by John Hughes |
  13. National Athletic Trainers’ Association Position Statement:Fluid Replacement for Athletes  Douglas J. Casa, PhD, ATC, CSCS et. al., University of Connecticut, Storrs, CT, Journal of Athletic Training 2000;35(2):212–224
  14. Exercise and Fluid Replacement  American College of Sports Medicine, Med Sci Sports Exer. 2007:39;377-390.
  15. Nutrition and healthy eating  With Mayo Clinic nutritionist Katherine Zeratsky, R.D., L.D., Mayo Clinic nutritionist, Aug. 2011.
  16. The Claim: Caffeine Causes Dehydration  By ANAHAD O’CONNOR Published NY Times: March 4, 2008
  17. Alcohol and Athletic Performance  UC San Diego Athletic Performance Nutrition Bulletin
  18. Alcohol and Athletic Performance  Gina Firth, LA LMHC NCC, University of Notre Dame, 2004.