As runners, we are confronted with the dangers of heat, since most locations have at least some periods in which the weather will be warmer than ideal for running. Not wanting to curtail our training during these times, we should make modifications to ensure that we are safe in warmer weather. The following are some tips to help deal with the heat.
75% of the body's weight results from H2O. Proper hydration before, during and after a run is critical in warm weather, because we lose a great deal of water through sweat. Fast fact: just a brisk walk in heat will generate up to 16 ounces of sweat (a pound of water). Failure to properly replace these fluid levels can lead to dehydration, manifested by cramping, nausea, heart palpitations and lightheadedness. When running, we should take a few small sips of water or replacement drink every 15 minutes or so as opposed to waiting until we feel thirsty. Once we begin to feel thirsty, we have already started to become dehydrated. After a particularly heated run, we should weigh ourselves and drink 16 ounces of water or replacement drink for each pound lost during the course of the run.
Runners are also advised to consider using sports replacement drinks instead of water when running in warm weather to help prevent hyponetrimia (a lower than normal salt concentration in the plasma) which can develop when the runner drinks too much water and the blood becomes diluted. We lose a great deal of salt through sweat and not replacing this salt can cause headaches, nausea and in severe cases, vomiting. Runners who only drink water during the race put themselves at risk because they are not replacing the salt that the body needs. Drinking sports replacement drinks which contain electrolytes can help the body to avoid becoming depleted of sodium.
Dressing comfortably is important. The clothing worn in warm weather conditions should be lightly colored and constructed of fabrics which are both lightweight and breathable. This will help to keep us cooler. Investing in gear constructed of fabrics that pull moisture away from the skin will also help to keep us more comfortable and prevent potential problems.
Exposure to the sun is also a concern when running in warm weather. Wearing a lightweight, breathable hat can help keep the sun off the face without causing us to overheat. We should always wear sunscreen to protect the skin in warm weather. There are several brands of sunscreen available which are designed specifically for use by runners and other athletes, because they are less likely to drip into the eyes and cause stinging or burning.
Small precautions will not only keep us safe, but will ensure faster, which is always funner.
Information from wikipedia, emedice from WebMD, and medicinenet.