Importance of Hydration
The most common cause of fatigue is dehydration. An effort to increase fluid intake should, therefore, reduce fatigue and increase energy, and be of particular value to people with chronic fatigue. Dehydration is a common cause of headaches. In a study, a group of patients with frequent migraine headaches were asked to drink more water and their headache status was assessed 2 weeks later. The number of headaches among the patients who increased their water intake was reduced by 21 hours, in comparison to the control group, which increased their number of headaches by 54 hours. Urologists are physicians who specialize in looking (internship), another group with chronic dehydration, have passed urine osmolality tests, encountered in college of 0.5, which indicates mild dehydration. This group has been shown to have a higher risk of developing painful and irritating urinary tract infection. High fluid intake has also been shown to reduce the risk of urinary bladder cancer. The incidence of kidney stones is increasing, the greatest risk factor being concentrated urine. High fluid intake increases the volume of urine passing through the kidneys and dilutes the concentration of minerals, so that they are less likely to crystallize and form stones. With diluted urine, volume of about 2L a day, kidney stone sufferers can be pain free and avoid more stone surgery.
Benefits of staying hydrated
Lifestyle also plays a major role in hydration. Those who work or exercise outside have a much higher chance of dehydration than those in less physical professions. Athletes especially need to be cautious, as dehydration can affect their performance on a very high level. About 6-7 days prior to exercising, athletes should drink extra water and swig plenty of fluids during exercise. Electrolyte imbalances are also a concern, so they should have a sports drink with carbohydrates. Losing as little as 2% of normal water volume in the body can lead to impaired performance and heat illness. Knowing the environment is also crucial; high altitude and hot, humid weather cause increased sweating and fluid loss. Climate controlled environments can be constructed to combat this, as demonstrated by the exertion of the Tokyo Olympic marathon race to Sapporo over concerns of high heat levels. An older person may not feel dehydration as easily as a younger person because the thirst mechanism weakens with age, further emphasizing the importance of sufficient water intake.
Staying hydrated is crucial to maintaining good health. The human body is composed of up to 60% water. The functions of these bodily fluids include digestion, absorption, circulation, creation of saliva, transportation of nutrients, and maintenance of body temperature. Water is an essential building block for the human body, and makes up a higher percentage of our body than what is described in many other articles. Water is the most important nutrient for the body, much more so than calories from food. In one week a person can live without food, however, in a hot climate a person can only live without water for a few days. Slight dehydration can cause headaches and dizziness, leading to heat stroke in extreme cases. There is a common myth about consuming 8 cups of water a day. This is in fact not based on hard evidence. The Institute of Medicine determined that an adequate intake for men is roughly about 13 cups of total beverage a day, and for women is about 9 cups. This is still depending on the individual, and can increase with temperature and physical exercise. Uniformly it can be said, more water should be consumed than food in hot climates and during exercise to prevent heat stroke. In contrast, many illnesses result in frequent vomiting, diarrhea, and fever. Patients suffering from these illnesses should drink plenty of water to prevent dehydration. It is widely recommended that water be drunk before feeling thirsty, that way it is less likely that the person will reach the point of dehydration.
Consequences of dehydration
When you’re low on essential fluids, your body can’t function properly. Nearly all of your body’s major systems depend on water to work – for example, the brain is about 70-80% water. If it’s hydrated properly, then mood swings, headaches, and loss of concentration can be avoided. However, if it’s not, then these are the first symptoms of temporary mild dehydration. Other consequences of dehydration include tiredness; it actually makes one feel more tired than normal. Mild dehydration is also one of the most common causes of daytime fatigue. An estimated 75 percent of Americans have mild, chronic dehydration. These are the people that would benefit most from increasing their water intake; not only for the added energy and vitality, but it helps keep the skin healthy (it’s the body’s largest organ), controls weight gain, and helps build/maintain muscle tone. Later down the line, the loss of muscle tone and weight gain leads to the two main health concerns in America: heart disease and diabetes. Keeping the body hydrated can prevent many serious conditions. According to The Centre for Disease Control and Prevention, not drinking enough water can lead to urinary tract infections (UTIs). Proper hydration helps cleanse bacteria from the bladder. More seriously, long-term dehydration reduces the amount of saliva available to protect the teeth and mouth, helping to avoid cavities and gum disease. This also holds for the rest of the bodily joints – dehydration leads to the shrinkage of water inside the joints, and without this lubrication, can cause pain from bone on bone contact (arthritis). Dehydration can have a very dangerous impact when the body is unable to cool itself through perspiration. This can in turn lead to a sudden rise in body temperature and heat stroke. At its crudest level however, the lack of fluid intake can lead to death. This happens when the body has lost so much water that it’s unable to function; the blood becomes too concentrated due to the lack of water, and the body goes into shock. Unbelievably, this is nothing new to the American public. In 2001, 20 college students had to be hospitalized and treated for dehydration after failing to drink enough water during exercise. This is down to a lack of education on how to prevent dehydration, and also the lack of emphasis on the importance of staying hydrated to take part in everyday activities.
Recommended daily water intake
One technique will be the AD (adequate consumption) approach counseled by the Food and Nutrition Board of the Institute of Medicine. This approach is based on a review of published research on the water requirements of healthy, sedentary men and women. The AI for total water intake is ready at approximately 3.7 liters (125 ounces) for men and 2.7 liters (91 ounces) per day for women. The AI sets a standard intake for ok hydration, assuming that about 80 percent of this intake comes from consuming beverages and 20 percent from food.
Today’s most common guideline is to drink six to eight 8-ounce glasses of water. However, the quantity you need varies relying on your weight, age, and sex, how active you are, what climate you stay in, and your usual fitness.
Strategies for Hydration
Eating hydrating foods is another way to increase your fluid intake. There are many fruits and vegetables that can contribute to a high fluid intake. For example, lettuce is 95% water and a watermelon, as its name suggests, is over 90% water. Other good sources include cucumber, celery, tomatoes, courgette, and peppers. Soup is the ultimate hydrating food and full of nutrition, especially in the winter months. By making a simple change from a sandwich lunch to a soup lunch, you can significantly increase your hydration and vitamin and mineral intake.
If you find you forget to drink, set a reminder. This may sound unnecessary, but if you are not in the habit of drinking fluids regularly, you may not feel thirsty. It takes several days to get into the habit of feeling thirsty and recognizing a need for a drink. Get into the routine of having a drink at times when you are likely to forget, for example, when working on the computer; every time there is a break in music, during advert breaks, or at each change of an activity.
Although drinking water is the most obvious way to stay hydrated, how many of us actually drink water regularly throughout the day? Strangely enough, fancying a drink rather than being thirsty is a sign of mild dehydration. If you find yourself feeling like a coffee or soft drink, it’s your body asking for a fluid. Get into the habit of having a drink with every snack and meal. Keep a bottle of water in easy reach and regularly take a swig.
Drink water regularly throughout the day
If you’re one of those people who only address their thirst once you’re dying of thirst, it’s time to reconsider your approach. Thirst is not an accurate gauge of your body’s hydration needs. By the time you feel thirsty, your body is already in the early stages of dehydration. Sip water throughout the day so that your urine stays consistently pale. Keep a glass or reusable water bottle by your desk and refill it every time you take a sip. Having water readily available is a great way to remind yourself to drink it. Set a goal. Example: “I will drink 8 cups of water today.” Markings on the bottle can help, a 1L bottle has 4 cups, 600ml has approximately 3 cups. Set deadlines: e.g. “By lunchtime, I will have drunk 2 cups of water.” This method works especially well for people who thrive on routine and schedules. Use a water drinking app. There are several mobile apps available designed to help people track their water intake. Usually, you would input your weight and the app would calculate a recommended daily water intake. Users then log their water, and the app keeps track of their daily and weekly intakes. These apps usually also allow the user to set custom reminders, and some will send notifications if the daily water intake has not been met. E.g. Waterlogged, Daily Water, iDrated.
Include hydrating foods in your diet
When considering how to stay hydrated, most people associate fluid intake with water consumption. However, it’s important to realize that many foods contain water and can contribute significantly to your daily fluid needs. A variety of fruits and vegetables can be an important and flavorful source of hydration. The highest water content fruits are comprised mostly of water. Examples include melons, oranges, and grapefruit which (in addition to being flavorful juicy snacks) are greater than 90% water. Cucumbers and tomatoes are an example of high water content vegetables. See the table below for examples of fruits and vegetables with high water content. (Melons, oranges, grapefruit are all >90% water; apricots, peaches, plums, cantaloupe, pineapple, berries, cherries, and pears are all >85% water; oranges, apples, pineapple, and grapes are all >80% water). These fruits and vegetables are a healthy and tasty way to increase hydration and help maintain a desirable fluid balance. Drinks such as milk and juice are composed mostly of water, but be aware that certain components of these beverages can act as diuretics. This will be discussed later on in section 2.3. Keep in mind that the most beneficial and cost efficient method to maintain fluid balance comes from the tap.
Limit intake of dehydrating beverages
In order to procure a healthy diet and lifestyle, it is essential to incorporate an adequate intake of water and hydrating fluids. However, it is just as important to be aware of the types of beverages that can lead to dehydration. Essentially, caffeinated beverages such as tea and coffee and alcoholic drinks act to promote diuresis. This is due to the diuretic effect they impose, causing more rapid loss of fluid from the body than they actually provide. In fact, approximately 200-300 mL of water is lost in the urine for every 1 cup of coffee consumed. Therefore, in terms of hydration, coffee acts equivalent to drinking twice the amount of coffee in water. Among the most obvious contributors to dehydration are drinks classified as soft drinks. A high intake of refined sugars found in soft drinks can lead to osmotic diuresis, where the large intake of sugar draws water out of body tissue into the intestine and urine, causing a fluid imbalance. High sugar intake can also lead to hyperglycemia causing increased urination, fluid loss, and thirst. This combination of factors makes soft drinks a particularly potent agent in dehydrating the body. As a comparison, it is useful to weigh the effects of these dehydrating beverages with their fluid losses against the consumption of water or a rehydrating sports drink to quench thirst. By doing so, it is hoped that an individual will begin to see the necessity in choosing more hydrating beverages to satisfy thirst and a lesser intake of dehydrating drinks.
Use reminders to drink water
The following explanation will outline different reminders which can be used throughout the day to increase the amount of water you drink. People are particularly forgetful when it comes to remembering to drink water. Reminders are therefore an essential tool to increase fluid intake. The most common example of a reminder to drink is leaving a full glass of water on a desk or in a place where it will be seen regularly, e.g. a kitchen. A visual reminder like this can be particularly effective and is more tangible than other well-known advice such as “drink when you feel thirsty”. Setting an alarm or alert on a mobile phone or electronic device reminds you at certain times during the day to stop what you are doing and drink a glass of water. This type of reminder tends to be useful for busier individuals who can get caught up in daily tasks. A newer approach to reminders to drink water has been the use of “hydration reminder” apps. These are simple apps that are usually free to download and work by calculating the user’s recommended daily water intake, and then setting regular alerts throughout the day to remind the user to drink. Some of these apps have additional features like tracking daily fluid intake and setting goals to drink more water. An advantage of apps like this is that these days many people are likely to have a phone with them at all times, and so the reminders can be heard or seen while at home or at work.
Hydration for Active Individuals
Strenuous activity increases the need for water. With as little as a 2% loss of body weight from sweating, there is decreased performance. It’s important to find the right balance. Not consuming enough water can lead to dehydration, but sometimes, there is such thing as too much water consumption. Drinking too much water can result in a condition called hyponatremia. This is when blood sodium levels drop too low and can lead to illness or death. It is very important to stay on the hydration offensive during physical activity. Dehydration occurs when you lose more fluid than you take in and your body doesn’t have enough water and other fluids to carry out its normal functions. You can become dehydrated if you don’t drink enough water and this can cause tiredness, headaches and decreased performance. The best thing to drink is water, but sports drinks are generally fine if you’re involved in high intensity exercise for more than an hour. Generally though, try to avoid drinks with caffeine, as these are diuretics and will cause you to lose more fluid than you’ve consumed. High protein drinks are also a bad choice. They can cause the body to use up more fluid and can also increase the risk of kidney damage. There have also been cases of protein drinks containing anabolic steroids, which could lead to disqualification or a possible ban from sports.
Importance of hydration during exercise
Dehydration is particularly detrimental to exercise in the heat, and it is well known that heat acclimation and exercise-heat stress induce body fluid loss. This was exemplified in a recent study on well-trained cyclists who rode a fixed intensity bout before and after a 10-day heat acclimation period in 30°C with dehydration induced during the post-exercise recovery period. Although performance was not significantly different, the level of heat stress was higher and the physiological strain greater post-acclimation, despite similar body weight loss and hydration status, due to a lower sweat rate and higher internal heat production during exercise. This led the authors to conclude that during heat-acclimated exercise in the heat, there is a limit to the compensability of heat stress and that fluid replacement is critical. Although there is evidence that hypohydration improves thermoregulation and physical performance during exercise in cool conditions, for most athletes, these are likely to be negated by the decrements in cardiovascular function and endurance. So whether or not hypohydration is beneficial in cooler climates, the risk is far too great to take into important competitions.
Pre-workout hydration tips
Don’t wait until you ‘feel’ thirsty to drink. Thirst is a signal that your body is already experiencing dehydration. The goal of pre-exercise hydration is to start the activity euhydrated (normal body water content) and to drink, if needed, to prevent excessive dehydration during the activity. Start exercising properly hydrated by drinking at least 16-20 fl oz of water 4 hours before exercise. This should be followed by 8-12 fl oz of water 10-15 minutes before exercise. If you are exercising for longer than 60 minutes, weigh yourself before and after exercise and consume 16-24 fl oz of water for every pound of body weight lost. Sports drinks with electrolytes and a carbohydrate solution are beneficial in maintaining fluid balance and providing an energy source during exercise. Drink them if you are exercising in extreme environments, i.e. hot, humid, greater than 2-3 hours. Lastly, it’s important to develop a personalized hydration plan to optimize fluid balance during exercise. This should be based on body weight changes during exercise and urine color changes post-exercise. An ideal post-exercise body weight should be within 2% of the pre-exercise weight. Dark yellow urine is a sign of dehydration. If you are dehydrated, drink 16-24 fl oz of water for every pound lost. The goal is to be optimally hydrated for the next exercise session.
Hydration during exercise
Dehydration during physical activity in the heat is a major medical problem and the “second leading cause of death” in some sports. Minimizing dehydration and achieving euhydration can result in improved exercise performance, higher core temperature, and lower HR. The major problem is that most athletes begin their physical activity in a less than optimally hydrated state. Drinking on the day of exercise is particularly important because it allows the athlete to begin exercise euhydrated. An ACSM Position Stand in 2007 outlined specific fluid recommendations for before, during, and after exercise. Using the guidelines from this statement, and with consideration for individual variability and needs it is possible to develop a personalized hydration strategy. During the period of exercise involving sweat losses, the major goal is to replace fluids and avoid excessive dehydration. The most effective way of doing this is by drinking to thirst, as this will prevent both over-drinking and under-drinking. Although there are specific sweat rate testing protocols, there are difficulties measuring these accurately and they are not practical for the everyday athlete. Maintenance of optimal body water percentage should be assessed by changes in body mass and urine colour. Due to the wide variability of sweat rates between individuals, variation in exercise intensity and duration, and use of different types of sports clothing, a one-size-fits-all fluid prescription is not ideal. It is estimated that most athletes will require 5-10 ml/kg body weight of fluid every 10-20 min to maintain hydration. This equates to about 3-8 fl oz. of water or sports drink every 10-20 min for a 155lb athlete. The massive variation allowed (2-fold difference) takes into account the wide variety of sweat rates. An athlete may accurately assess fluid preservation by checking their body mass changes to calculate sweat rate, then using this data to plan an individualized drinking programme for future exercise events. This is especially important in multi-day events. Urine colour can be assessed 3-4 hours post exercise and can be useful to ensure that an athlete has started in a hydrated state for the next event. Measures to estimate changes in body fluid percentage during exercise include bioelectrical impedance techniques, although they do not classify which water compartment has been lost or gained. Until the development of a practical and reliable method to determine fluid needs, these techniques find limited use in the sports field.
Post-workout hydration strategies
Consuming foods high in fluid content is also recommended to help with rehydration. Foods high in water content can contribute significantly to fluid needs and can enhance palatability of the diet, improving the overall eating experience. Studies have shown that consuming a diet that contains fruits or vegetables can improve hydration status. Since these foods are very healthy for us, consuming them regularly in the diet can also benefit overall health and can prevent chronic dehydration. Dehydration can also cause minerals to accumulate in the urine and impede onto kidney stones, fruits and vegetables that are high in water content reduce the risk of stone formation in the kidneys because the increased hydration prevents the minerals from concentrating and forming stones. Hormonal inadequacies can lead to certain nutrient deficiencies, one of the most common examples is osteoporosis. Physiological effects of osteoporosis can lead to an increased risk of fracture due to decreased bone strength. Consuming dairy products and other foods high in calcium can help to prevent this disease. Soymilk is also an excellent choice and contains similar nutrients to dairy milk. Electrolyte replacement beverages can also be a good food choice and are designed to help with rehydration. These beverages contain both fluid and electrolytes and can commendably replace fluid losses. They are also beneficial for providing athletes with a source of quick energy due to their carbohydrate content. Fluid replacement gels and other foods that are high in carbohydrates can also help to restore fluid balance. These foods are convenient, easy to use and can be taken with anywhere, making them a good choice for active people and athletes. They can also be useful for people who have limited access to fluids during the workday or find it difficult to take breaks from exercise. Since glycogen depletion is common in active individuals, consumption of carbohydrate-rich foods to restore glycogen stores can also increase water retention. For every one gram of glycogen stored, the body retains around three grams of water. Although this would not significantly increase total body water, it can still be beneficial for people who need to quickly restore body weight (such as athletes who have lost body water through sweating) because the retention of glycogen and water increases overall body weight. But despite this, it is important to remember that increased carb intake can also increase urine production.
Hydration in Specific Situations
To summarize: Fundamental guidelines for staying hydrated are the same for different situations. If you are going to be out in the heat, you must drink 16-20 ounces of water 1 to 2 hours before exercise. During your exercise, you should consume another 8 ounces every 20 minutes, even when you aren’t thirsty. When the exercise is completed, drink another 8 ounces of water. If the activity is an hour or less, water is the best choice. But if the activity is intense and lasts longer than an hour, a beverage with electrolytes is recommended. For events lasting half a day or more, or involving vigorous exercise such as basketball games or workouts at the gym, choose drinks that have electrolytes and about 6-8% carbohydrates. Some examples are Gatorade and Powerade – make sure to read the label on each product because the carbohydrate and calorie content varies. This is because electrolyte-containing drinks will help you replace both fluid and sodium losses. Though they do provide calories, they will not provide enough energy to interfere with ongoing exercise. Plan ahead and make sure you have an adequate supply. Water is good, but when the activity is more than an hour, a beverage with electrolytes and carbs is also a good option. Remember, when you are exercising, you lose more water than usual – sweating causes you to lose water more rapidly and breathe in a drier manner. So, it is important to drink more water than your thirst indicates. Always monitor your hydration status with the urine color chart, and if done consistently, this will help you drink the appropriate amount. A situation involving exercise and outdoor activities in the heat is the most common means of at-risk dehydration, and the above guidelines will help prevent dehydration from occurring in this context.
Hydration for hot weather
Before looking at specific recommendations, it is important to realize that the body has a remarkable coping mechanism when faced with heat. Initially, blood is shunted to the skin surface for cooling, but this results in more rapid dehydration, which causes a higher strain on the heart. However, with regular training in hot weather, adaptation to the heat occurs, whereby the body earlier starts sweating and loses fewer electrolytes and less water in the process. One way to assist this is to do some of your training in the heat so that this adaptation occurs. This should be approached with caution as anyone with certain medical conditions and those on particular medications may be more susceptible to heat illness. If your primary race is in a cooler climate, heat adaptation may be less important, and it may be wiser to avoid excessive heat exposure. Always stop any training and seek immediate medical attention if you feel dizzy, develop a headache, nausea, vomiting, muscle cramps, or weakness as these can be signs of heat stroke or more serious heat illness. During high intensity or long duration exercise in the heat, the rate of fluid loss can be up to 2L per hour. If this is maintained and there is no fluid replacement, dehydration will quickly ensue. It is recommended that you weigh yourself before and after exercise to determine your fluid loss rate. 1kg body weight loss is equivalent to 1L fluid loss. Anxiety about dehydration in athletes has resulted in the suggestion of drinking excessive quantities of fluid. This can lead to hyponatremia, a condition where low plasma sodium levels can result in nausea, vomiting, headache, bloating, and in serious cases, seizures, coma, and even death. This is of far greater concern than dehydration for athletes exercising in events of long duration. Due to this, it is important to judge your fluid replacement rate. This can also be calculated using the weight loss method, and fluids should be consumed at a rate similar to fluid loss. It is advised to drink cool fluids 5-10°C as this enhances absorption and palatability, and consumption of salty snacks and/or water with added electrolyte may help to maintain electrolyte balance.
Hydration for cold weather
When it is cold, it is easy to forget to drink fluids, but keeping well hydrated is just as important in cold weather as it is in the heat. In cold, dry weather, you can see your breath, which is water vapor exhaled from your lungs. The respiratory rate is higher in cold weather and there is more urine production, so the loss of water can be deceiving. It is easy to think you do not sweat in cold weather. However, you may be wearing a lot of clothing and sweating is less noticeable. Dehydration can impair your body’s ability to regulate heat and can make you more susceptible to hypothermia. It can also make you more tired. If the weather is cold and also at high altitude, the risk for dehydration is greater. This is because fluid losses increase at higher altitudes and the sensation of thirst is depressed. Drinking adequate water is the best way to stay well hydrated. The body’s signal for water intake is thirst. The sensation of thirst is a good indicator of hydration state, but in cold weather, people are less aware of their thirst. They may ignore the signal to conserve time or because it is cold taking sips of cold water. There is evidence that both increased thirst and urine output are triggered by the body’s efforts to warm and humidify the airways during breathing. So people may need more water than they are aware. Fluid requirements can be assessed by measuring body weight before and after exercise and drinking to replace losses, or by simply paying attention to urine color. Drinking a large amount at one time may cause a cold sensation in the stomach and the water will be excreted. So small, frequent drinks are best. 500-600 ml (17-20 ounces) of cool fluid 2 hours before activity is sufficient for short-term activity. During an event, a drink such as a sports drink or water with a piece of fruit may actually be more appealing in cold weather than a cold drink. This amount is sufficient to replace sweat losses for activities up to about 3 hours in length. Seltzer water or a very small amount of lemonade can add variety to fluid intake at times when plain water is less appealing. Of course, your urine should be a pale yellow, unless you take supplements containing B vitamins which will cause a deep yellow color. Then you may be alert that you have mild dehydration if urine color is darker than normal. If you are trying to make changes in your hydration practices, the first step is to become aware of your usual intake, and then try to match the environment and your intake with the information in the table below on staying well hydrated.
Hydration during illness or fever
When someone is not well and they are sick or they have a fever, they will lose more fluid than when they are well. If we think that an average person loses about 2-3 litres of fluid each day in normal living, this may increase if the person has a fever, diarrhea and/or is vomiting. It is therefore important to try and still achieve the recommendations outlined in Section 2. Generally, the best guide as to whether a person is getting enough fluid is the color of their urine and if they are producing very little and it is very dark, they are likely to be dehydrated. In this instance, it may be worth buying an oral rehydration sachet from the pharmacy which you mix with water. This is because not only are they a good source of fluid but they also contain sugar and salt which can aid fluid absorption. If a person does not feel like eating or has poor appetite, it may be an idea to consume more soups, broths, and flavored ice-lollies to increase fluid consumption. High sugar fluids such as fruit juices and fizzy drinks and drinks with caffeine should be avoided in unmixed form as they can sometimes aggravate diarrhea. Including these drinks as one part of a 1:1 dilution with water can make them suitable. Finally, if advice is sought from a doctor, it may be worth seeking advice from the doctor on when the person should return to consuming normal levels of fluid.