Photo by Chris Ralston on Unsplash
The question of how much water we should drink has had a fair amount of airtime, although the answer is not as straightforward as you think. As I looked further into hydration and aging I uncovered some pitfalls to be aware of, some interesting facts about how we should consume water, and discovered that water may not always be the best form of hydration.
While I often don’t drink as much as I should, I’ve only experienced a form of severe dehydration once. I spent the day out on the water watching sailing racing, in a small inflatable boat. It turned out to be a beautiful sunny day with light breezes. Not able to have a convenience stop I had just taken one bottle of water with me, but as the racing stretched out in the light wind I realised I hadn’t taken enough.
Once I hit shore I went straight to the bathroom, then bought water and started making up for the deficit. However, I was too late. My mind started playing tricks on me. I couldn’t think how to spell words when texting, and was having trouble remembering people’s names. This is what dementia feels like, I thought. Fortunately I came right in a few hours after the fresh water supply kicked in, but it was a real insight into the effects of dehydration.
How Much Water Should We Drink?
You know the answer to this one already – you think. This is a simple question on the surface, but unsurprisingly the answers vary.
Look at this for example – Adequate daily water intake is defined in the United States by the Institute of Medicine at 3.7L for men and 3.0L for women and in Europe by the European Food Safety Authority as 2.5L for men and 2.0L for women. That’s quite a difference with the American guidelines being 50% higher than the European ones!
And it gets more interesting with one study by the American Physiological Society suggesting that the answer may depend on our age. In a study they conducted of adults 40-79 year there was a huge variation in fluid intake, between 1.4 – 7.7L for men and 1.2 – 4.6L for women daily. Their guidelines recommend older men should drink 2L, and older women 1.6L daily. The most interesting thing about this study was that none of the participants in the oldest age group showed signs of clinical dehydration.
How Your Body Stores Fluid
There is a clue to why we need less water as we age in the way that our body stores fluid.
Have you noticed the spare tire that appears around your abdomen around 50? It’s a common occurring change that has nothing to do with whether a person is normal weight, underweight or overweight. It is a degenerative loss of muscle mass accompanied by the replacement of muscle fibres with fat or even connective tissue, and it is known as sarcopenia.
Water makes up a large percentage of organs, tissue and body parts. Muscle, for example is 79% water. Water is stored in and between cells that make up the body. As we age less of our total body weight is made up of water. The decreasing water percentage through the years is due in large part to having more body fat and less fat-free mass. Fatty tissue contains less water than lean tissue, so your weight and body composition affect the percentage of water in your body.
Why Dehydration is an Issue as We Age
This change in body composition is one of the things that makes us more susceptible to dehydration as we age. It is one of three age-related changes often cited.
The second issue is that your thirst sensation diminishes. This makes it a less reliable reminder of when to drink water. A study at the University of Melbourne found that older adults don’t drink enough water because their brains and bodies don’t coordinate sensory signals about thirst, but they were unable to establish whether it was the body signals lacking or the interpretation by the brain that was at fault.
Thirdly, your body is less efficient at producing concentrated urine. Your kidneys make urine by filtering wastes and extra water from your blood. Less concentration means that a higher percentage of water is being flushed through the body, and less is being retained.
These issues make it really important to establish good hydration habits now, so it does not become a problem in older age.
What Aids Water Absorption
Drinking large amounts of water on its own may not be the best way to stay hydrated. In an article in TIME Magazine David Nieman, a professor of public health at Appalachian State University and director of the Human Performance Lab at the North Carolina Research Campus says that “plain water has a tendency to slip right through the human digestive system when not accompanied by food or nutrients. This is especially true when people drink large volumes of water on an empty stomach.”
Sips of water are a much better way to take on fluid without overloading the kidneys. Drinking water before or during a meal or snack is another good way to hydrate. “Drinking water with amino acids or fats or vitamins or minerals helps the body take up more of the water,” says Nieman.
The same article then sited a 2015 study in the American Journal of Clinical Nutrition, in which researchers compared the short-term hydration effects of more than a dozen different beverages. The researchers concluded that several drinks—including milk, tea, and orange juice were retained in the body for long periods of time. Therefore these beverages may be good options for situations like long car drives where access to fluids is limited, or you don’t have access to a bathroom, like me on the boat.
A Guide to Dehydration
As well as monitoring our water intake it is good to know what dehydrates you, what signs of dehydration to watch for and what nasty complications might befall you if dehydration goes untreated. The following chart gives you a quick overview.
One thing I didn’t realise is that dehydration is linked to bad breath, but it makes sense since your body needs plenty of water to make saliva or spit. When you’re dehydrated, you have less saliva. This causes more bacteria to grow in your mouth. Brushing your teeth and drinking plenty of water helps to get rid of odor-causing bacteria.
Key Points to Help you Stay Hydrated
- Establish good hydration habits now, don’t rely on the thirst sensation
- The amount of fluid you need is a personal thing and will diminish as you age. Monitor your urine colour as a good indicator.
- Retain muscle mass as much as possible to aid the retention of water in your body.
- Sips of water over time is the best way for your body to absorb water and not overload the kidneys.
- Consider an alternative drink like milk or orange juice for situations where free access to fluids is limited.
- Drink fluids immediately before or with meals to aid absorption.
- Take in additional fluid following exercise, in heat waves and when you are ill.
References
American Physiological Society: Just How Much Water Do We Really Need? The Answer May Depend On Our Age
Markham Heid: Why Drinking Water All Day Long Is Not the Best Way to Stay Hydrated
Ronald J Maughan, et al: A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index
W L Kenney 1, P Chiu: Influence of age on thirst and fluid intake.
Doreen Gille: Overview of the physiological changes and optimal diet in the golden age generation over 50
Healthline: What Is the Average (and Ideal) Percentage of Water in Your Body?
Carolyn Colwell: Lack of Strong Thirst Signals Leads Elderly to Drink Too Little
WebMD: What is Dehydration? What Causes It?
Heather Ogden-Handa
Good to meet you! I’m a marketer and writer interested in aging and longevity. I see lots of great information out there, so I’m keen to share topics that take my interest. Over time I hope the knowledge and community around this blog will have a positive impact on the healthy lifestyles of many individuals.