Proper hydration is important year round, but it can become particularly critical during the summer months. July and August are usually the hottest months of the year in the United States, which is also usually the time that people are engaging in more outdoor activities and athletes begin ramping up training for fall sports. Unfortunately, this time of year is also a prime time for a potentially serious condition to occur: dehydration.
How does dehydration occur?
Dehydration can occur by losing too much fluid (usually through sweating) or by not drinking enough fluid. You may recall from school that the human body is made up of approximately 70% water, so this fact alone illustrates how important proper hydration is for us!
The body has mechanisms in place to urge us to drink fluids, most notably the feeling of thirst. This is the most obvious sign that our body is running low on water; however, by the time you feel thirsty, you are actually already experiencing mild dehydration.
How can you tell if you are dehydrated?
There are many other symptoms that can signal dehydration. Some examples, according to Medline Plus, include the following:
- Mild dehydration: Thirst; dry mouth; decreased urination; yellow urine
- Moderate dehydration: Dry, cool skin; headache; darker yellow urine; muscle cramps
- Severe dehydration: Irritability or confusion; dizziness; rapid heartbeat and/or rapid breathing; shock (decreased blood flow to important organs); unconsciousness.
Keeping an eye out for these signs are important for everyone, but they are particularly critical for two groups: older adults and athletes.
Who is most at risk for dehydration?
Older adults have a decreased response to thirst and are more likely to be on a diuretic. These factors make it important for this population to drink fluids constantly throughout the day, even when they may not feel thirsty. This is especially important during prolonged exposure to heat during activity, such as walking, gardening, mowing the lawn, etc. These activities may not always seem strenuous, but they can cause the body to sweat profusely. During activities that are of a more vigorous intensity (such as jogging/running, hiking, biking, etc.) the sweating effect is more pronounced and proper hydration more critical.
Athletes exercising in the heat can lose an average of 2.0 liters of water through sweat per hour (which is equal to a large bottle of soda!). Not replacing the lost water can cause serious fluid imbalances and dangerous rises in core temperatures. Unfortunately, student athletes are often the victims of poor monitoring of hydration status. According to sports nutrition experts William McCardle and Frank and Victor Katch, “Hyperthermia (dangerously high body temperatures) has occurred more than 100 times over the past 30 years among football players who died from excessive heat stress during practice or competition.” These situations are completely preventable by making sure to either have water or an electrolyte replacement beverage at all times during outdoor activity in the heat.
What can you do if you suspect dehydration?
If dehydration does occur for any reason, there are several steps that can be taken, depending on the severity of the condition:
- Sip water or suck on ice cubes (or an electrolyte sports drink)
- If heat exhaustion is also a problem, lie down somewhere cool and focus on breathing slowly
- For severe situations, go to a hospital immediately
Notice that the first suggestion is to sip water. While replenishing fluids is a critical step to treating dehydration, it is possible to drink too much water at one time, which isn’t healthy either. Rehydrate slowly if you become dehydrated!
How much fluid should you be drinking?
A good rule of thumb is 2 cups of water 20 minutes before being active in the heat. For athletes or anyone engaging in vigorous exercise, you can weigh yourself before and after activity takes place to gauge how much fluid you need to take in to replace losses. The amount of weight lost in pounds should be replaced at least 100% to account for fluid loss in sweat and urine. For example: If 2 lbs., or 32 oz., is lost during an hour of activity, 32 oz. (or 4 cups) of water or a sports drink should be ingested over the next hour. In terms of choosing between water and a sports drink, always choose the sports drink if activity is lasting longer than an hour. Below an hour, water is usually sufficient.
So whenever you leave the house this summer, always bring a water bottle with you! And remember to always drink more when exercising or being active in the heat. Dehydration is 100% preventable, as long as you provide your body with the fluids it needs every day.
McArdle W, Katch FI, Katch VL (2013). Exercise, Thermoregulation, Fluid Balance, and Rehydration (4th ed.). Sports and Exercise Nutrition (pg. 319-335). Baltimore, MD: Lippincott Williams and Wilkins.
Popkin B, D’Anci KE, Rosenberg IH (2010). Water, Hydration, and Health. Nutrition Review; 68 (8): 439-458.
U.S. National Library of Medicine (2013). Dehydration. Retrieved from: http://www.nlm.nih.gov/medlineplus/ency/article/000982.htm