Walking Injuries and Prevention How Much Water You'll Need for Your Walk By Wendy Bumgardner Updated January 10, 2019 Pin Flip Email Print Alistair Berg/DigitalVision/Getty Images More in Walking Injuries and Prevention Walking for Weight Loss Treadmill Walking Long Distance Walking Beginners Walking Shoes Walking Fast Gear and Clothing Pedometers and Fitness Bands Clubs, Partners, and Programs Treadmill Workouts View All When you go for a long walk or a short walk, it's important to drink enough water and other fluids so you don't get dehydrated. But it can take some planning to know how much to take along, or how often you'll need to be able to refill your water bottle or hydration pack. How Much Water You Need The rule of thumb is that you need to drink 3 to 6 fluid ounces of water each mile, or drink approximately every 15 to 20 minutes. That is 1/2 cup to 1 cup of water per mile. Let thirst be your first guide and drink when thirsty. The chart below will help you know how many bottles that translates into. For longer walks, follow the drinking guidelines for distance walkers. You may need to weigh yourself before and after long walks to see whether you are getting enough water and replacing the salt lost to sweat. How Much Water to Carry The most common ways to carry water with you are in 16-ounce disposable bottles, 20-ounce refillable sports bottles, and hydration packs of various sizes (50/70/100 fluid ounces or 1.5/2/3 liters). The chart below shows the range of the number of bottles fills and hydration pack fills you will need during your walk. How Much Water You May Need Based on Walking Time Walking Time mL fl. oz. 16 fl.oz/0.5L 20 fl.oz 32 fl.oz/1L 50 fl.oz./1.5L 70 fl.oz./2L 100 fl.oz./3L 15 min. 125-250 4-7 1 1 1 1 1 1 30 min. 125-250 7-14 1 1 1 1 1 1 45 min. 375-750 11-21 1-2 1 1 1 1 1 1 hour 500-1000 14-38 1-2 1-2 1 1 1 1 1 1/4 hour 625-1250 18-35 2 1-2 1-2 1 1 1 1 1/2 hour 750-1500 21-42 2-3 1-2 1-2 1 1 1 1 3/4 hours 875-1750 25-49 2-3 2-3 1-2 1 1 1 2 hours 1000-2000 28-56 2-4 2-3 1-2 1 1 1 2 1/4 hours 1125-2250 32-63 2-4 2-3 2-3 1-2 1 1 2 1/2 hours 1250-2500 35-70 3-5 2-4 2-3 1-2 1 1 2 3/4 hours 1375-2750 39-77 3-5 2-4 2-3 1-2 1 1 3 hours 1500-3000 42-84 3-6 2-4 2-3 1-2 1-2 1 3 1/2 hours 1750-3500 49-98 4-7 3-5 2-4 1-2 1-2 1 4 hours 2000-4000 56-112 4-7 3-6 2-4 2-3 1-2 1-2 4 1/2 hours 2250-4500 63-126 4-8 3-7 3-5 2-3 1-2 1-2 5 hours 2500-5000 70-140 5-9 4-7 3-5 2-3 1-2 1-2 5 1/2 hours 2750-5500 77-154 5-10 4-8 3-6 2-3 2-3 1-2 6 hours 3000-6000 84-168 6-11 5-9 3-6 2-4 2-3 1-2 6 1/2 hours 3250-6500 91-182 6-12 5-9 4-7 2-4 2-3 1-2 7 hours 3500-7000 98-196 7-13 5-10 4-7 2-4 2-3 1-2 7 1/2 hours 3750-7500 105-210 7-14 6-11 4-8 3-4 2-3 2-3 8 hours 4000-8000 112-224 7-14 6-13 4-8 3-5 2-4 2-3 The chart shows a wide range, as you will need to see what works best for you. The simplest rule of thumb is "drink when thirsty." If you find you are running out of the water and are still thirsty, you'll know you need to be at the higher end of the range rather than the lower end. On the other hand, it is possible to drink too much plain water and wash out your body salt, resulting in hyponatremia, which is also dangerous. Don't force yourself to drink too much, drink when thirsty. When to Use Sports Drink When you walk for over an hour, especially if you are sweating, you may want to begin using a sports drink that replaces sodium and other electrolytes you are losing. Alternatively, have a snack that has some salt. But keep drinking enough fluids. Either bring powdered sports drink with you add to water, or switch to a prepared sports drink. Carrying Water: 1 Pint (500 mL) Weighs a Pound Keep in mind that water and sports drink weighs quite a bit. If you want to save on weight but need more water, you'll need to make a plan for where you'll refill your bottle or hydration pack. What Should You Drink on a Distance Walk or Marathon? For a workout of 10 kilometers (6.2 miles) or more, minutes or more, the International Marathon Medical Director's Association (IMMDA) recommends drinking a sports drink, and not diluting it with extra water or alternating sports drink with water. The carbohydrates and electrolytes in sports drinks help the body absorb water faster, and provides energy for the body. If you dilute the sports drink, you decrease the benefits. However, some walkers and runners (especially those who want to lose weight) ignore this advice in order to take in fewer calories. During a marathon or race, they should drink carbohydrate-containing sports drink for performance. For walking workouts, they could use a low-calorie sports drink to replace salt without adding calories. However, the IMMDA also recommends that during a marathon, participants drink whichever beverage most appeals to them, relying on their body to know whether they need more sodium or more water. Race directors and walking event hosts need to have both water and sports drink available at water stops. This is good advice for walkers and runners on long training walks and runs as well. Have both available to you and drink whichever appeals to you at the moment. How Much Should You Drink on a Distance Walk or Run? There are dangers in drinking either too much or too little. Drink too much and you risk hyponatremia, which is low blood salt level and fluid overload. Drink too little and you risk becoming dehydrated. Your needs will vary with many factors, including the weather, your body's reaction to the exercise demands, sweat rate, and more. Weighing yourself before and after exercise can often help you know whether you are drinking too much or too little. The guidelines say that a weight loss of more than 2 percent or any weight gain are warning signs that justify immediate medical consultation and indicate that you are drinking too much or too little. By weighing yourself and adjusting how much you drink on your longer training sessions, you will know whether you need to drink more or less. Drink to Thirst During Long Workouts Erase the old advice that you can't rely on thirst. Evidence says that thirst is the best protection for athletes when it comes to drinking the correct amount. Drink when you are thirsty.Don't drink if you aren't thirsty.Don't drink at every water stop at an event just because it is there or your companions are drinking.Rely on your thirst unless you discover it is leading you wrong, from weighing yourself before and after a workout. Drinking Guidelines for Walkers and Slower Runners Drinking no more than 1 cup of water per mile is a good rule-of-thumb for walkers and slower runners, defined as anyone who takes more than four hours to complete a 26.2-mile marathon or a pace of more than 10 minutes per mile. Your weight determines the range. Drink 1/2 cup if you weigh 100 pounds and 1 cup if you weigh 200 pounds. The slower you are, the less you should drink. While a fast runner may need 4 liters of fluid for a marathon, a walker or slow runner needs only 2.5 to 3 liters for the entire event. Your thirst may not kick in as fast if you are in extreme heat and not yet acclimated to it, or in cold weather, or if you are over 65. In those cases, you may need to time your drinking rather than strictly be relying on your thirst. Calculating Your Fluid Needs Your needs may change based on the weather, your conditioning, and other factors. IMMDA provides this method of determining your fluid needs: One Hour Test Weigh yourself nude before the walk or run.One hour test: Walk or run or alternate walking/running at race pace for one hour, just as you will do during the race. IMMDA recommends one hour to get the sweat rate you will have during the endurance event.Write down how much you are drinking, in ounces, during the 1-hour walk or run.Weigh yourself nude after you finish the 1-hour walk/run. Subtract from starting weight. Convert the difference in body weight to ounces (multiply pounds by 16).To determine hourly sweat rate, add to this value the volume of fluid consumed (from Step 3).To determine how much to drink every 15 minutes, divide the hourly sweat rate by 4. This becomes the guideline for fluid intake every 15 min of a walk/run.Record the weather and conditions on your test day. Do the test again on a day with different weather and conditions, so you can see how your sweat rate reacts to different conditions. A Word From Verywell Your body is under extreme stress during long-distance running or walking. You need to ensure you have access to fluids and you are able to drink when thirsty. Don't risk running dry. It can be wise to wear a hydration pack to ensure you will have fluids available to you when you want to drink. Was this page helpful? Thanks for your feedback! Looking to start walking off the weight? Our free guide offers tips, workouts, and a printable schedule to help you get on the right track. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Maharam LG, Hew T, Siegel A, Adner M, Adams B, Pujol P. IMMDA’s Revised Fluid Recommendations for Runners and Walkers. IMMDA. 6 May 2006. (Current as of 2018). Maharam LG, Siegel A, Siegel S, et. al. IMMDA's Health Recommendations for Runners and Walkers. IMMDA Body, March 20, 2010. Sawka MN, Burke LM, Eichner ER, et al. American College of Sports Medicine Position Stand. Exercise and Fluid Replacement. Med Sci Sports Exerc. 2007;39(2):377-90. (Current 2018) Continue Reading Article How to Drink Right During a Marathon Article Ditch the Energy Drinks When Exercising Article 18 Tips for Drinking Right for Fitness Walking List The 10 Worst Pieces of Walking Advice Article Marathon Training and Race Day Diet, Fluids, and Energy Snacks Article Do You Know When and How Much To Drink for Exercise? Article Hydration Tips for Before, During, and After Your Runs Article Are Your Walking Shoes Flexible Enough? Article Is Cold Water Good or Bad When Exercising? Article Why Do My Hands Swell Up When I Walk? 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