Stay cool -considerations and strategies for avoiding heat illness.
When it comes to spending time outside in the summer, having a bit of knowledge about the factors affecting your body’s ability to cool itself, can mean the difference between a good, hot workout and a massive headache (or worse!) Here are eight things to consider.
Acclimatization: This is the process of becoming accustomed to a new climate or new conditions. Slowly adapting your schedule to expose yourself to high temperatures over the course of a few weeks will not only increase your body’s ability to start sweating faster, but will also reduce loss of salt in the sweat. These two changes help you keep your heart rate and core body temperature lower during exercise.
Hydration: Improper or poor hydration will reduce the body’s ability to sweat at a rate that effectively cools the core temperature leading to a significantly higher chance of heat injury. Aim for 8 ounces of water every 20 minutes when working or training in a hot climate.
Environmental Temperature: Convection (cooling by air, water, or a surface that is below your body temperature moving against your skin) and radiation (loss of heat to the cooler environment from the body) only work if the temperature gradient from your skin to the environment is lower than your body temperature. When you're exercising in temperatures higher than your body temperature, the only means by which your body can cool itself is through evaporation from sweating.
Wind: Wind places more air molecules into contact with your skins and can be an important factor in cooling the body through convection as well as evaporation
Metabolic Rate: Considering that your body’s core temperature is directly proportional to your rate of work, the metabolic heat production that warms your body up when exercising on a cold day will be working against you in a hotter environment. Limiting exercise to light or moderate intensity may be an important consideration when the temperature and/or humidity levels are high.
Environmental Humidity: Evaporation of sweat is dependent on the water vapor pressure gradient between the skin surface and the environment. When the ambient temperatures are hot, the relative humidity is an extremely important variable to consider as at a higher humidity, the ability to cool your body via evaporation will be significantly reduced
Clothing: Tank tops and shorts are ideal attire as they expose maximum amounts of the skin surface to air to aid in evaporation. If less clothing is not an option due to work conditions or sun exposure, choose cotton or performance materials that will “wick” sweat to the surface for evaporation.
Fitness: A high level of physical fitness is related to a lower risk of heat injury. The more fit you are, the more you can tolerate work in the heat, the faster you can adjust to the heat, and the more you will sweat to cool yourself.
Tips for exercising in the heat
Know your signs and symptoms of heat illness.
Exercise in the cooler parts of the day to maximize on cooling your body via radiation and convection.
Drink water before, during, and after exercise.
Wear shorts and a tank top to expose as much skin as possible.
If a possible have a fan or cold rags on hand to assist in cooling the skin
Gradually increase your exposure to high heat/humidity to safely acclimatize (Start with 5 min of exercise in the heat then increase 2 min per day).
Track your heart rate while your workout and make sure you are modifying your intensity to stay in a zone of moderate intensity no higher than 70 percent of your maximum heart rate ((220-minus your age) x .70).
