I am asked often about water and fluids. How much do we need? What are the best things to drink? So, I thought I would do some research and address some of the most frequently asked questions and clear up some of the unfounded myths and misinformation that are floating around about water and hydration.

Are there health risks associated with not getting enough fluids?
Yes, chronic dehydration has been shown in scientific studies to be associated with many negative health outcomes including heart disease, bladder cancer, colon cancer, UTIs, and constipation. In one study of 20,000 men and women, participants who drank 5 or more glasses of water per day had half the risk of dying from heart disease than those that drank 2 or less.

A 2013 study in the British Journal of Nutrition looked at the effects of fluid deprivation on mood in women. Their results showed increased sleepiness, fatigue, and confusion, all of which were immediately reversed by taking in fluids. Another 2011 study looked at the effects of mild dehydration on cognitive performance and mood among young males and found a negative effect regarding working memory and increased tension, anxiety, and fatigue.

Even mild dehydration can have a negative physiological effect causing headaches, fatigue, and reduced physical and mental performance.

Do all of your fluids have to be water or do you get hydration from other beverages too?
Other beverages can provide you with fluids too. Coffee, tea, milk and milk alternatives are all good choices and can help you meet your fluid requirements.  Many of us, though, rely on soda, juice, sports drinks, energy drinks, etc. for hydration instead of water. All of these are loaded with added sugars adding to our already high intake of sugars and increasing our overall calorie intake.

Another common source of fluids are alcoholic drinks. We can get fluids from moderate beer intake, but wine and liquor are actively dehydrating.  Alcohol has a diuretic effect and so has the potential to dehydrate.  If you’ve ever felt that morning after headache from one too many glasses of wine or liquor drinks, then you know this to be true.

What about caffeinated drinks? Do they act as a diuretic?
A very common myth is that we get no fluids from caffeinated drinks and in fact they act as a diuretic, leaving us more dehydrated. In a 2011 study in the British Journal of Nutrition researchers compared the impact of tea versus water on hydration and found no significant difference. In another 2014 study looking at coffee and its effect on hydration similar results showed no significant difference when comparing moderate coffee intake and water.

So, it turns out the long believed notion that caffeine dehydrates is a myth. Tea and coffee not only can hydrate, they can also provide antioxidants, making them a good choice both nutritionally and for hydration. The problem is what we put into our teas and coffees. If they are loaded with sugar and/or cream then obviously that is another issue separate from hydration.

Is it better to drink cold or room temperature water?
This is one I’m asked often. Some people think that room temperature or body temperature is better absorbed and can help with weight loss. Cold water has actually been shown to be better and more quickly absorbed, about 20% faster than room temp water. 

You may have heard of some celebrities and websites talking about the miracle of hot water with lemon and touting its health benefits, including weight loss.  While it can provide some vitamin C and can help you cut calories if you are replacing a higher calorie soda or coffee drink with it, it is no magic potion – despite all the hype and hubbub you may hear or read.  

In the end, the impact of the temperature of the water is minimal. You are more apt to drink water at the temperature you prefer, so stick with what you like.  

How much water do we really need?
You have probably heard that you need eight 8 ounce glasses of water per day. Ultimately, it turns out that there is not a whole lot of scientific evidence to support that specific recommended amount.

Individual water needs can vary depending on many factors like body size, activity level, and temperature, but the current recommendation for most adults from the Institute of Medicine and the World Health Organization is 4-7 eight ounce cups of water per day for women and 6-11 eight ounce cups of water per day for men.  The rest of our fluid needs can be met through other fluid choices and the foods we eat.   Food provides about 20% of our fluids – varying depending on the types of foods that are chosen. Whole foods, like fruits and vegetables, can provide a significant amount of fluid and help us stay hydrated – just one more benefit!

So, there you have it. Hopefully that answers some, if not all, of your questions and clears up some confusion. My advice, shoot for the recommended amount of 4-7 cups for women and 6-11 cups of water for men, drink tea and/or coffee in moderation, and fill your diet with whole foods like fruits, vegetables, and dairy products (like milk and yogurt) that will naturally provide the water and fluids you need to feel good and stay energized and healthy.