Welcome to the long, hot days of summer!
Yes, we are in the middle of the time when daylight hours are extended and everybody stays out later. However, summertime also brings us some of the warmest temperatures of the year turning many of us (including myself) into human sweat machines. As if the hot weather was not bad enough by itself, any outdoor physical activity, such as running or biking, raises the body temperature even more causing the body to cool itself down by releasing heat in the form of water, mainly via sweating. As gross as this process may seem, it is vital to keeping our bodies from overheating and shutting down; however, it is important to pay attention to how much you are sweating so that you can replenish your losses and avoid dehydration.
How do you know how much to drink after a sweaty day outside? Here are two simple ways to determine your fluid needs:
1. Monitoring changes in body weight- Take your body weight immediately before and after participating in outdoor activities or exercise. Subtract your body weight after sweating from your body weight before sweating. Any weight loss that you have experienced is due to sweat losses! For every pound lost, drink 16 ounces of water. Sports drinks should only be considered for replenishment during physical activity lasting greater than 60 minutes; otherwise, calorie-free water should do the trick.
2. Monitoring urine color and volume- Notice the color and volume of your urine when you use the restroom. Is it a pale yellow color? Are you urinating regularly? If your urine is a concentrated, dark yellow or if you are not urinating several times throughout the day, then your body needs more fluids, preferably in the form of water.
Next time you are enjoying the warm weather outside, remember to keep hydrated and drink before you feel thirsty. Thirst is actually the first sign of dehydration, and without correction, you will experience weakness, loss of appetite, fatigue, headache, decreased ability to concentrate, increased heart rate, and eventually, dizziness and heat exhaustion. In general, you should strive to drink 8 to 12 cups of fluids per day. However, still continue to monitor your weight and urine because those measures are the official judge of hydration level.
Now, go and enjoy the summer heat! Just remember to take a water bottle along with you, and don’t be afraid to add mandatory drink breaks into your schedule. Your body will thank you.
Rolfes, S., Pinna, K., & Whitney, E. (2012). Understanding Normal and Clinical Nutrition (9th ed.). Wadsworth: Belmont, CA.