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Water does a lot of things. In our bodies, it acts as a medium in which chemical reactions occur, a solvent, and the fluid in which nutrients and waste products get transported around and out of the body. Water also helps us to regulate our body temperature and keeps our joints lubricated and shock-resistant.
Water is involved in practically every physiological process that takes place in the body, so it makes sense that it makes up a large portion of our body weight. In infants, water makes up 75% of total body weight; that percentage decreases as we age to around 55% in older adults. Men usually have a greater proportion of water in their bodies due to the higher percent of lean body mass that they carry.
So, water is important, and it takes up a very significant fraction of our body weight. Yet, many people don’t drink enough water. If you are one of those people, then give yourself a pat on the back for taking some time out to learn more about why you need to start hydrating more. You are taking a step towards a better version of yourself, and that's what matters most.
In this article, I am going to discuss 7 things that can happen when you perpetually ignore that water bottle that's sitting on your desk.
Go ahead and take a few sips as you make your way down the list.
1: Not drinking enough water can reduce your brain power
There is some limited evidence which suggests that being dehydrated could have a negative impact on short-term memory, attention, coordination, alertness, concentration, and mood. Not drinking enough water could affect your cognitive function for many reasons, one of them being reduced brain activity. Research using functional magnetic resonance imaging (fMRI) to monitor brain activity has shown that poor hydration can lead to reduced activity in some regions of the brain. This is not surprising when you consider that the brain is about ¾ water.
Studies in children have linked poor water intake to reduced short-term memory and executive function, too (see: here, here, and here). Conversely, better hydration has been linked to enhanced cognitive flexibility and short-term memory.
This argument could have been avoided had these two both been adequately hydrated.
2: Not drinking enough water can restrain your athletic performance
It is important to start exercise in a well-hydrated state and to hydrate well during and after exercise. This is because when you lose a lot of water during exercise, your body has to work harder to pump blood and regulate your body temperature, two things that are essential for preventing heat stroke.
Less water in the body also reduces VO2 max. VO2 max refers to the maximum amount of oxygen that your body can absorb and use while you are exercising. It is a common measure of aerobic fitness and is often applied in the context of endurance sports like running. Even if you are not a runner, it is a good idea to do things that maximize your VO2max, since it is an indicator of how well your heart and lungs are working.
Are you bad at running, or do you just need to drink more sky juice?
3: Poor water intake can negatively affect your kidneys
For people who have had kidney stones in the past, drinking enough water to increase urine volume to 2 liters per day was shown to reduce kidney stone recurrence. This is from one study however – more are needed to better understand the connection between water intake and kidney stones.
Consuming enough water may also slow down the deterioration of your kidneys. Not hydrating enough, (drinking less that 2 liters of water per day) has been observed to be linked to chronic kidney disease (CKD).
4: Poor water intake can affect your weight
Not drinking enough water has also been associated with having a higher body mass index (BMI). Conversely, being well-hydrated has been linked in multiple studies (see this study, and this one) to having a lower BMI, waist circumference, and percent body fat.
Hydrating well can help you to maintain a healthier body weight by making you feel less hungry. In my own experience working with clients, I have found that people often mistake thirst for hunger. This can lead to overeating, as you may reach for a snack instead of a cup of water multiple times throughout the day if you are not good at differentiating between the two signals. Therefore, increasing water intake if you are in a dehydrated state could likely help to prevent overeating.
You may THINK you need this doughnut, but what you really need is some H2O.
A quick note - if you have a higher BMI, then there is a good chance that you actually need to drink more water than the recommended intake of 3.7 liters per day for men and 2.7 liters per day for women, since these estimates do not account for people in larger bodies.
5: Failing to hydrate well can harm your heart
Chronic dehydration is one of multiple factors that can lead to high blood pressure, venous thromboembolisms (a thromboembolism is a blockage in a blood vessel caused by a blood clot), heart disease, and stroke. This is because when you aren’t properly hydrated, the total volume of blood in your body decreases. In order to make sure that your organs are still getting the oxygen and nutrients that they need – and clearing out waste products – your heart beats faster and your blood pressure goes up. As if that wasn't enough, your blood also gets thicker and saltier, so that makes it even harder for your heart and blood vessels to keep circulation going.
Cutting down on fatty, fried foods will help your heart, and so will drinking that liquid ice.
6: Skipping out on water intake can also affect your blood sugar
Low water intake has also been linked to higher blood sugar levels in multiple research studies (see this one, and this one). This is because being well-hydrated reduces the concentration of sugar in your blood by increasing the total volume of blood in your body. Basically, drinking the right amount of water creates a healthy balance between the liquid in your body and the solids dissolved in that liquid.
This is something that I have observed myself when working with people with type 2 diabetes; oftentimes, high blood sugar can be a result of your blood being too concentrated. A common first step for people with diabetes who are experiencing hyperglycemia, or elevated blood sugar, is actually to drink a glass of water to help bring their blood sugar level down.
7: Low water intake can cause constipation
If you have trouble emptying your colon regularly, it could be because you are not drinking enough water. Dehydration has been shown to increase the risk of constipation.
Let's do a quick review of how our colons get filled in the first place. For your body to make feces, water must be absorbed in the large intestine until that familiar brown waste product is formed. However, if you do not have enough water in your body, your body will try to retain whatever water it still has in order to keep doing its job of keeping you alive, resulting in there being less water in the colon. This leads to stool that is dry and harder to pass.
Struggling on the throne? Before you buy a laxative, you may want to try drinking more of mother nature's laxative - water.
How much water to drink:
You have ample reasons to drink more water now, but, how much are you supposed to drink, anyway?
The National Academy of Medicine (NAM) (formerly known as the Institute of Medicine) recommends* that adults consume the following amounts of water per day, in liters:
Men: 3.7 L
Women: 2.7 L
Pregnant women:3.0 L
Lactating women: 3.8 L
*Note: this includes plain water, other liquids, and foods which contain lots of water.
For reference, if you use disposable water bottles, those typically come in 1/2 L size containers.
These are just general recommendations, of course. How much water YOU need depends on many factors, including age, sex, and body weight. Certain temporary factors may also play a role in how much water you need to drink in a given day. For example, exercise, hot weather, or illnesses like fever, diarrhea, and vomiting can increase your water needs.
One good way to gauge if you are consuming enough water is to listen to your body. While this may take practice, it is indeed possible to sense when your body is trying to communicate to you that it needs more water. It does this in two ways:
The thirst signal, and,
The color of your urine
Let’s start with the thirst signal.
When you are dehydrated, your blood becomes more concentrated. In the brain, the hypothalamus has detectors called osmoreceptors which detect this change in blood concentration. The hypothalamus then signals the posterior pituitary gland, also found inside the brain, to produce the hormone vasopressin, which is also known as antidiuretic hormone (ADH). This hormone tells your kidneys to make less urine so that you don’t lose too much water. The final step of this signaling cascade is a dry feeling in your mouth. If you are used to your mouth feeling dry, however, you may not feel like you need to drink more water. In that case, you can try referring to your body's second way of telling you that it needs more liquids.
Now, it's time to talk about the color of your pee.
The next time you go to the bathroom, take a look at the color of your urine. A healthy urine color is pale yellow. Once you get into the amber or honey-colored urine category, that generally means that you need to drink some more water. Generally speaking, if your urine is totally clear, you may be drinking too much water. This could be problematic, as it could lead to low electrolyte levels over time. Electrolytes are important for keeping your muscles working and your heart beating, so it is important not to over-hydrate.
Charts like this one can be helpful. Source: Hotel Dieu Grace Healthcare
Alright, that's it for today!
References:
The many roles of water in the body:
Jéquier E, Constant F. Water as an essential nutrient: the physiological basis of hydration. Eur J Clin Nutr. 2010 Feb;64(2):115-23. doi: 10.1038/ejcn.2009.111. Epub 2009 Sep 2. PMID: 19724292.
Salas Salvadó J, Maraver Eizaguirre F, Rodríguez-Mañas L, Saenz de Pipaón M, Vitoria Miñana I, Moreno Aznar L. Importancia del consumo de agua en la salud y la prevención de la enfermedad: situación actual [The importance of water consumption in health and disease prevention: the current situation]. Nutr Hosp. 2020 Oct 21;37(5):1072-1086. Spanish. doi: 10.20960/nh.03160. PMID: 32960634.
Weight:
Chang T, Ravi N, Plegue MA, Sonneville KR, Davis MM. Inadequate Hydration, BMI, and Obesity Among US Adults: NHANES 2009-2012. Ann Fam Med. 2016 Jul;14(4):320-4. doi: 10.1370/afm.1951. Erratum in: Ann Fam Med. 2020 Nov;18(6):485. PMID: 27401419; PMCID: PMC4940461.
Kidney stones:
Bao Y, Tu X, Wei Q. Water for preventing urinary stones. Cochrane Database Syst Rev. 2020 Feb 11;2(2):CD004292. doi: 10.1002/14651858.CD004292.pub4. PMID: 32045491; PMCID: PMC7012319.
Blood sugar:
Roussel R, Fezeu L, Bouby N, Balkau B, Lantieri O, Alhenc-Gelas F, Marre M, Bankir L; D.E.S.I.R. Study Group. Low water intake and risk for new-onset hyperglycemia. Diabetes Care. 2011 Dec;34(12):2551-4. doi: 10.2337/dc11-0652. Epub 2011 Oct 12. PMID: 21994426; PMCID: PMC3220834.
Pan A, Malik VS, Schulze MB, Manson JE, Willett WC, Hu FB. Plain-water intake and risk of type 2 diabetes in young and middle-aged women. Am J Clin Nutr. 2012 Jun;95(6):1454-60. doi: 10.3945/ajcn.111.032698. Epub 2012 May 2. PMID: 22552035; PMCID: PMC3349456.
Constipation:
Arnaud MJ. Mild dehydration: a risk factor of constipation? Eur J Clin Nutr. 2003 Dec;57 Suppl 2:S88-95. doi: 10.1038/sj.ejcn.1601907. PMID: 14681719.
Diaz S, Bittar K, Mendez MD. Constipation. 2023 Jan 31. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 30020663.
Institute of Medicine Recommendations:
Institute of Medicine. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. Washington, DC: National Academies Press. 2004.
Example of urine color chart from Hotel Dieu Grace Healthcare: https://www.hdgh.org/uploads/BariatricAssessmentandTreatmentCentre/dehydration%20urine%20colour%20chart.pdf
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