It’s summertime and you’ve forgotten to bring along your water bottle for your afternoon hike. Should you go back and get it, or keep hiking and worry about it later.
The rule of thumb is eight—eight glasses of fluid a day per person, increasing fluid intake for exercise, hot weather, high altitude or low humidity.
If you hike without adequate hydration, you have a greater chance of developing fatigue, headaches and general irritability.
Drink before you get thirsty, and drink until your urine is only slightly yellow. Water is preferable over juices and sports drinks if you’re trying to watch calories.
The US national Research council suggests that another rule of thumb— match one ml of water for every calorie consumed. In other words, if you eat 3,000 calories worth of food, you have to drink 3,000 milliliters of water.
Remember that if you don’t want to wake up at night for a bathroom stop, don’t drink within two hours of going to sleep. Also, alcohol and caffeine have diuretic side-effects—they increase urine output.