As we move into summer it is important to remember how heat affects your body and the implications of exercising in hotter temperatures.
Exercising increases the workload of your heart as it has to provide oxygen, via your blood, to the exercising muscles. Exercising in heat further increases the workload of your heart as your body must maintain a constant temperature of 37°C. To accomplish this constant temperature in hot weather your body expands the blood vessels in the skin. Your heart then pumps blood to your skin, as well as your exercising muscles, allowing your blood to be close to the surface. As you perspire, your sweat evaporates from the skin allowing it to cool down.
Heat-related illnesses occur when your sweat cannot evaporate fast enough to keep your body cool. This can be exacerbated with increased humidity as water vapour in the air prevents your sweat from evaporating as easily as it would in drier conditions. Signs and Symptoms of heat-related illnesses include deterioration in exercise performance, weakness, fatigue, muscle cramps, nausea or vomiting, excessive sweating, headaches, dizziness or light-headedness, visual problems, confusion, irritability, low blood pressure, and increased heart rate.