DEAR DR. BLONZ: The parents of our son’s soccer team bring the halftime refreshments. Typical items are water and orange slices. Recently a parent brought sweetened juice-flavored drink packets that he claimed would be better than water because they would drink more. It wasn’t a sports drink. An animated discussion followed. It has all been resolved, but I wanted to know your thoughts. -- M.V., Walnut Creek, California
DEAR M.V.: Our bodies work best within a narrow temperature range. There are automatic processes designed to conserve body heat when temperatures fall. If our core body temperature drops, we instinctively reach for some kind of cover or warm layer; if it drops too low, we begin to shiver, which is a purposeful activity that takes advantage of the heat given off by working muscles. But when we engage in continuous physical activity, it’s an excess of heat that becomes the issue. When that happens, the body’s largest excretory organ -- the skin -- assumes center stage.
Small blood vessels dilate near the skin’s surface to radiate heat into the ambient air. The skin will dampen with perspiration, purposely losing heat through the water’s evaporation. With a long, intense workout, electrolyte loss -- mostly sodium, but also potassium -- can become an issue. These minerals are normal elements in bodily fluids and flow out with perspiration, helping to explain the salty nature of skin that has been sweating.
Being overheated and short of water at the same time will place an extra burden on the heart: It’s forced to work harder to pump blood into the working muscles while also pushing fluids out to the skin surface to maintain the cooling process. If the body is not well-hydrated, it can begin to overheat, which can impact athletic efforts as well as the post-workout recovery. In the extreme, it can progress to a dangerous condition known as heatstroke.
Being well-nourished before the event, and resupplying what’s being lost in the process -- including water, energy and electrolytes -- can help during the workout and afterward. Plain water is fine for shorter efforts, such as those under an hour, and adding oranges provides flavor and a source of energy and nutrients from real food.
Sports drinks, which usually include sweet flavorings and some electrolytes, do encourage young athletes to drink more; this works well for those who play sports for extended periods of time, or who sweat excessively. That parent was correct in saying that some sugar can improve palatability and encourage consumption.
Beverages with added sugar are not cast in a positive light these days. But this is an exception, in that the muscles are at work. A small amount of sugar in a drink can help performance by helping maintain blood glucose, a key source of energy for muscles involved in athletic efforts. But “small” is the operative word here, as too much sugar slows absorption and leads to bloating and cramping.
Sweetened juice drinks not specifically designed as sports drinks can be too sweet, tend to contain artificial colors and flavors, and are unlikely to include electrolytes (check the Nutrition Facts label).
Water and oranges make practical sense for team events, such as your son’s soccer games. For individual athletes, I favor homemade sports drinks made from water and fresh fruits. My recipe can be found at: tinyurl.com/krkj8mx.
Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.