Water is necessary for life to exist. Of course, you know that already! You can live for quite a while without food but dehydration can kill you in less than a week. Still, not everyone agrees on how much water you should drink and whether other beverages are a suitable substitute for water. If you work out in a hot environment, you can lose water very quickly through sweating and dehydration becomes a very real possible problem.
At first, dehydration makes you feel tired, and, if you’re working out, your performance suffers. Yet, if you continue to exercise without rehydrating, you run the risk of heat stroke or heat exhaustion. Even if you aren’t actively working out, you need to replenish the water you’re constantly losing. So, it’s important to be knowledgeable about hydration for your own health and safety. Let’s look at some of the truths and myths about drinking water and hydration.
Truth or Myth: You Can’t Drink Too Much Water
Myth. Unfortunately, this is one that too many people still believe. Marathon runners have died taking this advice. Drinking large quantities of water during prolonged exercise can dilute the sodium in your body and lead to a life-threatening sodium deficiency. That’s why during prolonged exercise you should drink a beverage that contains electrolytes, like sodium, potassium, and chloride. This really only applies when you’re exercising for longer than an hour or you’re working out in a hot environment. Otherwise, water is an acceptable rehydration beverage.
Unfortunately, the signs and symptoms of a low sodium level are similar to those you get when you’re dehydrated. This causes athletes to drink even more water, further worsening the low sodium level. Yes, it is possible to drink too much water when you exercise for a long period of time.
Truth or Myth: Drinking Water Can Help You Lose Weight
Partial truth. Some studies support this idea. For example, a randomized controlled study showed that participants who drank two glasses of water before a meal ate 80 fewer calories, on average, relative to those who didn’t. Plus, they lost five pounds of weight that the control group didn’t. Guzzling water causes stomach distension that feeds back to your brain that you’re getting full.
Drinking water may also give your metabolism a subtle boost. For example, a study showed that drinking a half-liter of cold water boosted metabolic rate by almost 30%. While drinking more water might give you a slight edge if you’re trying to lose weight, what you eat and how much is still more important. Where drinking water might be most effective is when you use it as a replacement for sugary beverages.
Truth or Myth: Caffeinated Beverages Are Dehydrating
Myth. Research shows that drinking caffeinated beverages doesn’t dehydrate you. The Institute of Medicine put this idea to rest. Based on research, drinking beverages with caffeine, like coffee or tea, leads to an overall net increase in fluid balance similar to what you get when you drink non-caffeinated beverages. Yes, you may have to urinate more often when you drink coffee but that’s partially because it irritates the bladder. Plus, your body develops tolerance to the diuretic effects of caffeine when you drink it regularly. So, if you enjoy coffee and tea, sip it in moderation. It counts towards keeping you hydrated.
Truth or Myth: Drink Based on Your Thirst
Partial truth. This one’s a bit controversial. Thirst is not an ideal indicator of how hydrated you are. You typically experience thirst when you’re 3 to 5% dehydrated. Yet, there’s no firm evidence that this degree of dehydration is harmful. However, beyond this point, you would likely feel fatigued and, possibly, experience a mild headache.
Of interest is a study showing even mild dehydration changes endothelial function, the way blood vessels respond. This could lead to problems like a rise in blood pressure or even a higher risk of heart attack or stroke if you already have heart or blood vessel disease. Another reason to stay hydrated – drinking more fluid lowers the risk of kidney stones in people who are susceptible to them.
Truth or Myth: You Should Drink 8 Glasses of Water Daily
Myth. Your fluid needs may be greater or less than 8 glasses daily. So many factors go into determining how much water you need. If you’re more active or live in a hot environment, you lose more water through sweating and will have higher fluid requirements. Another factor is your diet. If you eat lots of fruits and vegetables, you supply your body with water from the high fluid content of these foods, so you may not need to drink as much.
Medications can also impact your fluid requirements. Certain heart and blood pressure medications have a diuretic effect and lead to fluid loss. You’ll need to drink more if you take one of these. Age and body size are other factors that affect your fluid requirements. For example, the elderly are more prone to dehydration and, for them, thirst may not be a good indicator of whether they need to drink more fluid. So, there is no “one size fits all” for how much you should drink. As a general rule, if you’re drinking enough, your urine should be pale yellow or straw colored, although if it’s colorless, you might be overdoing it.
If Plain Water Doesn’t Appeal to You
If you don’t like the taste of water or the lack of taste, jazz it up a bit. Infused water is all the rage. Add your choice of fruit slices, slices of cucumber, berries, or herbs to water and stick it in the refrigerator for three or more hours to let the flavors infuse. Another option is to add fruit, like berries, to an ice cube tray and fill it with water. When it freezes you’ll have flavored ice cubes that also look pretty bobbing around in your water glass. If the water in your home has an off flavor, consider getting a water purifier. If it tastes better, you’ll drink more. Also, don’t buy into the bottled water fad. Studies show that some bottled water is water from a spigot. Plus, it’s usually in plastic bottles. The plasticizer from the bottles can leach into the water.
The Bottom Line
Don’t underestimate the importance of staying hydration but don’t buy into these all too common myths about drinking water.
CJASN January 2007 vol. 2 no. 1 151-161.
Medicine.net. “Drinking Too Much Water and Exercising Dangerous”
N Engl J Med. 2005 Apr 14;352(15):1550-6.
Nutrition Review. “Drink Water to Curb Weight Gain? Clinical Trial Confirms Effectiveness of Simple Appetite Control Method”
The Beverage Institute for Health and Wellness. “Laying the Caffeine – Dehydration Myth to Rest”
Boschmann, et al. (2003). “Water-Induced Thermogenesis.” Journal of Clinical Endocrinology and Metabolism. 88 (12).
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