Safely exercise in the heat with a few easy tips…

New year, new you is definitely the trend at this time of year, and for those of us lucky enough to live in sunny Brisbane, there is always a trend towards taking your exercise outside. There is nothing wrong with that! But when the weather turns warm, it can be important to exercise caution, too. Moving your training outdoors can increase the risk of heat-related conditions, specifically, severe heat exhaustion and exertional heat exhaustion.

In both cases, exhaustion means that the body is unable to continue to exercise or do other physical activity. Your body simply stops, though you may remain at very high risk of internal damage or death (not to scare you, but it should, a little). The difference between the two conditions is “why” it stops:

Severe heat exhaustion typically involves a combination of nervous system and muscular fatigue, dehydration, and/or electrolyte depletion from high sweat levels. Your brain can also get in on the act, and send altered signals to other body systems and interfering with proper function. Once you reach a threshold level of dehydration and/or fatigue, your brain is going to say “no more” and you’re gonna hit the wall, hard.

Exertional heat exhaustion happens when the body’s internal temperature gets too high. To prevent your internal temperature from increasing even more, your brain shuts your body down – physical work can no longer continue. This is a serious, high-risk condition if left unrecognised or untreated; part of the physical shutdown includes your body’s ability to cool itself. Without fast recognition and quick cooling, overly high internal temperature can lead to organ failure and death.

Both conditions can affect healthy people even when the environment is relatively cool, though the risk increases significantly in hot or humid weather. Fortunately, there are precautions you can take that will significantly decrease your risk.

• Exercise during the cooler parts of the day. This is probably more enjoyable anyway!
• Wear cool clothing. Shorts, T-shirts, and tank tops are good here (but don’t forget the sunscreen). Cooler clothing will prevent excess heat from being trapped in your body, and will help improve the cooling that occurs with sweat evaporation.
• Exercise in an air-conditioned environment. If this is your option of choice, note that it is still beneficial to exercise when its cooler outside, as the outdoor temperature can have an impact on your body temperature.
• Take your time to get used to the heat. The ACSM Position Stand on Heat Related Illness recommends a 10-14 day acclimatisation period, where you gradually increase your time in the heat (to stay on the safe side, do this in a non-exercising fashion by just spending time outside). This precaution can be especially important if the weather has gotten really hot, really fast, or if you have travelled to a new area where the weather is different.
• Increase your exercise volume and intensity gradually. In plain speak, start easy and short. Heat tolerance has been linked to fitness levels, with better fitness creating better heat tolerance.
• Check your medications. Some prescriptions and over the counter medicines can decrease heat tolerance. Talk to your doctor or pharmacist to make sure you’re not at increased risk.
• Stay hydrated! This is one of the best ways to avoid any heat-related condition. Many factors can contribute to dehydration, so sweat alone is not a good indication. Adding an extra 1.5 to 2.5 cups of water for a shorter workout (under an hour) is a good starting point, but exercise in heat and/or humidity may require much more than that.
• Stay hydrated, part two! Sweat losses can be surprisingly large. A useful way to track how much fluid to replace is to weight yourself before and after your workout, and aim to drink two cups of water for every pound lost.
• Stay hydrated, part three! Sweat can mean electrolyte losses as well as fluid. If you’re normally a heavy sweater, or are sweating a lot in a given workout, replacing water with a sports drink may be a good option.

While heat-related conditions can be quite serious, they are easily avoided by taking the right precautions. Remember that some people may be more prone to heat-related conditions and that each person has a unique level of heat and exercise tolerance. But you can sweat smart. So get out there and enjoy the summer!