Health and wellness trends are everywhere. It’s hard not to get caught up in personalized health products and fads unique to your needs. We all want to find the secret to boosting energy levels and feeling more youthful. But what about the idea of something as simple as drinking more water? After all, 71% of the Earth’s surface is water. The human body is composed of 60-80% water. Heck, astronauts are even searching for liquid water in the cosmos. One thing is for sure, water will always be in demand because it’s what’s keeping us all alive.
Drinking water and staying hydrated has become a motto I live by. I attribute this strong habit to my athletic past and years of playing competitive volleyball. If you’re sweating it out, you better be drinking up! But how much water does a person typically need? And is it possible to drink too much water?
Let’s first look at the physiology and what water (or lack of water) actually does to our body. When dehydrated or in a state of “hypohydration”, a number of different things occur. We see a reduction in blood plasma volume, increase in plasma sodium, the renin-angiotensin-aldosterone system becomes activated, thirst sensations increase, and vasopressin anti-diuretic hormones increase. These scientific words might sound a little complicated, but in a nutshell, the body receives a signal telling it to hold on to water. Low volumes of fluid in the body decreases the amount of blood ejected out of the heart, lowering blood pressure and reducing blood flow to muscles. As a result heart rate increases, as well as body core temperature, and perceived level of exertion. So in other words, keeping the body hydrated helps the heart pump blood more easily through the blood vessels to muscles and helps the muscles work more efficiently.
Acute short term effects of hypohydration include reduced exercise performance, worsened mood, impaired cognitive function, altered ability to regulate temperature, and decreased blood sugar regulation. In the long term it can have more serious consequences such as hypertension, increased risk of blood clots, fatal coronary heart disease and stroke. The thicker the blood is, the more difficult it is for it to flow freely throughout the body, stressing the heart. Research supports evidence that suggests not drinking enough water also induces inflammation, reduces endothelial function (the thin membrane that lines the inside of the heart and blood vessels), and may affect arterial stiffness.
So how much water do you need? Our bodies are composed of about 60-80% water yet we are constantly losing it through sweat and urinary excretion. You’ve probably heard of the 8 x 8 rule. Drinking eight ounces of water, eight times a day adds up to roughly half a gallon. However, everyone comes in different sizes and shapes with different activity levels, meaning there is some variability in what is appropriate. One of the best ways to monitor your level of hydration is by checking the color of your urine. Pale to clear urine shows adequate hydration, while dark yellow suggests you need more water in your body. If you aren’t producing sweat during exercise like you normally do, that is another warning sign. Also, if you’re feeling thirsty that’s your body already telling you you’re becoming dehydrated. Weighing yourself is another excellent way to monitor the amount of water in your body, and especially helpful for elite athletes. Weigh yourself before and after exercise to determine the need for additional water intake. For every pound of sweat you lose, that’s a pint of water you’ll need to drink to replenish.
What about sports drinks? Are all liquids created equal? According to the Cleveland Clinic, if you are participating in low to moderate exercise, water is all you need. However, higher intensity exercise or longer duration exercise in warm weather will require more. Replace the fluids lost, but also replenish the sodium and potassium you are losing through sweat. Those participating in marathons and drinking only water may be vulnerable to a condition called hyponatremia. This is a condition in which sodium levels in the blood are too low. Cells in the body start to swell up due to the excess fluid. Symptoms include nausea, fatigue, headache, confusion, cramps, irritability, and seizures. Electrolyte gel packs and sports drinks such as Gatorade are helpful in increasing sodium levels. But what about other non-water beverages? Just because soda and other carbonated drinks are liquids, it does not mean they are hydrating you. In fact, caffeinated drinks are similar to diuretics, which will do the opposite. Juices and fruit drinks tend to have more sugar and carbs that can upset your stomach and not even contain sodium. Only beverages or foods containing water will count towards your daily needs. Conclusion: Water is best but balance is key.
A healthy individual should be able to naturally balance the amount of water coming in and out of the body. We call that homeostasis; the self-regulating process of maintaining a constant environment. Fluid imbalances can occur when you lose more water than you take in or when you drink more water than you can get rid of. Remember that an increase in water in your body means an increase in blood volume, which will make your heart have to work harder. Otherwise healthy individuals will have no problems increasing water intake because they can regulate it; but people who take certain medications or those who have underlying conditions may not be able to handle a rapid increase in blood volume. Therefore, typical water recommendations aren’t for everyone. In cases of heart failure, fluid may collect in the lungs and body tissues because the heart does a poor job of pumping it to the kidneys. Those with chronic kidney disease may also struggle to excrete excess fluids. Be sure to listen to your doctor’s recommendations if you have other medical issues or are taking medications affecting fluid balance (ex: diuretics or anti-diuretics).
Those over 50 years of age may need to take precautions. Older adults are less likely to have optimal levels of hydration because of factors including lower basal total body water, altered extracellular fluid sensing, blunted hormonal responses, and impaired kidney function. A study reported in the American Journal of Nursing, compared men 51 to 60 years of age with those 20 to 28 years of age. During a strenuous 10-day hill-walking excursion, the older men had less thirst and became progressively dehydrated; younger participants had no dehydration. Even though you may not feel thirsty, it is advised to sip water throughout the entire day. This generation of folks may also be taking other prescription medications that may affect hydration, in addition to already being predisposed to having balance issues or having other health conditions.
One major benefit to water is that it is calorie free! But does it really help you lose weight? An article posted by John Hopkins University lists ways in which staying hydrated may help you manage your calorie intake.
- Our brain can sometimes mistake thirst for hunger. According to Melina Jampolis, an internist and board-certified physician nutrition specialist, you may be able to decrease your appetite by drinking water if you are, in fact, low in water and not calories. It also passes through the system quickly, stretching the stomach and sending a signal of fullness to the brain.
- Research supports the theory that drinking water before a meal can also reduce appetite. People who drank two glasses of water immediately before a meal in a small 2016 study ate 22% less than those who didn’t drink any water prior to eating.
- Science also tells us drinking water creates a thermogenic effect, meaning our body has to expend energy to warm up the fluid to body temperature. As a result your metabolism speeds up. A study published in the Journal of Clinical Endocrinology & Metabolism determined that drinking two cups of 71 degree water led to a 30% average increase in the metabolic rates of 14 healthy adults.
- Don’t expect massive weight loss due to thermogenic responses, but know that replacing non-water beverages with water, overtime, can reduce the amount of liquid calories consumed. Keep in mind there are 140-195 calories in soda/pop, 154 calories in a can of beer, approximately 136 calories in a cup of juice, 50 calories in a 20 oz bottle of Gatorade, etc. Staying hydrated can also influence other healthy behaviors that will more directly lead to weight loss.
- When you are dehydrated or consuming a lot of salt, your body retains water. This can lead to extra pounds on the scale. By drinking water you can urinate the extra fluid out of your body.
In the physical therapy setting, we commonly treat patients recovering from surgical procedures. Water plays a critical part in the body’s healing and recovery processes. Blood flow brings oxygen and nutrients to muscles and the healing tissues. When dehydrated, blood volume is low and can delay wound healing. Drinking water also helps prevent post surgical complications by helping your bowels run smoothly (as prescribed opioids can cause constipation), decreases risk for blood clots, and assists protein synthesis needed for muscle repair.
Water is necessary for every human system and function. Everything from your skin, to your brain, to the functioning of your heart is affected by water. Knowing factors such as current health status, age, and level of physical activity will guide you in determining your daily water intake. Instead of grabbing for the caffeinated drinks, try a glass of water first. If you already know your water intake is lousy, I recommend gradually adding it in during meals, substituting water for other beverages you are drinking, incorporating additional foods rich in water content into your diet (ex: watermelon, strawberries, lettuce, cucumbers, etc.), or simply sip it throughout the day. I personally find myself more motivated to drink water after purchasing a new water bottle, especially if it has volume measurements on it. Figure out what you like. I like room temperature water because it quenches my thirst better and is easier for me to drink. Others may prefer it chilled or with slices of fruit in it. Sipping may be easier if you choose a water bottle with a straw instead of lid. There is plenty of evidence based research out there supporting the benefits of water. Try it out for yourself and see how you feel!