Staying Hydrated in the Summer Heat

This year in the Tri-State area, it feels like we skipped spring and went straight to summer. Without a gradual warmup for our bodies to get used to, it’s more important than ever to focus on staying hydrated as the temperature continues to climb.

Whether you are training for a marathon, playing a round of golf or sitting by the pool, it’s also important to be aware of the environmental conditions that may increase your risk of dehydration.

Sweat evaporation is our body’s most effective way of cooling off and maintaining our core body temperature. If the weather is more humid, it’s easier to overheat because your sweat doesn’t evaporate quickly. If the weather is dry – even if the temperature is hotter – the heat index will be lower because your sweat will evaporate quickly and cool your body off.

Activities During the Heat: How Hot is Too Hot?

If you’re asking yourself “is it too hot to golf today?”, the answer might be yes. If it’s an activity you are committed to – such as football practice or a 10K race – follow strict heat prevention guidelines, listen to your body and keep lots of water handy.

Dr. Miller says it is important to maintain adequate hydration before, during and after activity. In general, cool water is the best choice for fluid replacement, especially for activities that last one hour or less.

“The emphasis on drinking water is front and center during hot weather,” says Dr. Michael Miller, head of the Sports Medicine department at St. Elizabeth Healthcare. “If you’re outside in the heat for a longer event – greater than one hour – sports drinks can also be beneficial. The electrolytes and carbohydrates can help with longer endurance events.”

Dr. Miller recommends slowly increasing your exercise time and intensity over two to four weeks as your body adjusts to the hotter temperatures. For example, if you’ve run on a treadmill all winter, it’s not the best idea to start your outdoor running on a day with a high heat index.

Instead, Dr. Miller suggests starting at cooler, shadier times of day such as early morning or evening when the sun is low in the sky and the heat index is lower. Gradually work up to exercising during the high heat and humid times of day to help your body adjust. Conditioning your body to work out in the hot weather will help you avoid heat-related illnesses.

Calculating the Heat Index

The heat index reflects the temperature your body feels, not necessarily what the actual air temperature is. A heat index chart on St. Elizabeth’s website can help you calculate the heat index during a range of hot temperatures.

This chart was adapted from the Kentucky High School Athletic Association and is used to help high school athletic teams exercise safely in hot weather, as well as to provide hydration guidelines and other heat index safety tips. Highlights include:

  • Under 95-degree heat index: Optional water break every 30 minutes (ideally 10 minutes per break).
  • 95 to 99-degree heat index: Mandatory water breaks every 30 minutes (ideally 10 minutes per break). Recheck heat index regularly; reduce time of outdoor activity.
  • 100 to 104-degree heat index: Mandatory water breaks every 30 minutes (ideally 10 minutes per break). Recheck heat index regularly; reduce time of outdoor activity. If air conditioning is unavailable indoors, reduce indoor activities as well.
  • Above 104-degree heat index: Stop all outside activity until it’s cooler. If air conditioning is unavailable indoors, stop all indoor activity as well.

Dr. Miller recommends using a handheld digital sling psychrometer for on-site heat index calculations, especially for outdoor practices and activities. The heat index can change from location to location, even from one end of the playing field to the other. An on-site heat index reading ensures that the safest heat prevention guidelines are being maintained for athletes.

Don’t try to push through the heat – be smart and give your body what it needs to stay safe.

“It’s important to maintain a healthy diet as well as hydration during sports practices or other long activities,” says Dr. Miller. “It’s the best way to perform well, too. When in doubt – get out of the heat and drink some water.”

If you are interested in learning more about staying hydrated in the summer heat, call the St. Elizabeth Sports Medicine department at (859) 301-5600.