No one is moving a single step more than necessary. The side-walk cafes and parks are full of people, even at midnight. Without air-conditioning, apartments are simply unbearable. The news reported a spike in death rates this week. For now it's a heat wave: what will happen if the climate does change and 40°C becomes the new norm?
There's a fundamental difference between chronic cold and extreme heat. In the cold, a person can try putting more layers, bundling up in a blanket or sitting close to whatever heating devices are available (which, admittedly, may be none).
Heat is, in many ways, more difficult to escape. For those struggling with fuel bills for air-conditioning devices or even room fans, the trying to moderate high outdoor temperatures can drive up energy bills: Research shows that electricity demand for cooling increases 1.5% to 2.0% for every 0.6°C increase in air temperatures, starting from 20°C to 25°C. When temperature soar to extremes like 35°C or more, the effect is amplified.
But like cold, excessive heat leads to health impacts that should not be taken lightly. It negatively affects the human body by overwhelming its built-in temperature regulating mechanisms, which often leads to general discomfort, respiratory difficulties, heat cramps and exhaustion, non-fatal heat stroke, and heat-related mortality. Dehydration is very common and can quickly become quite dangerous: without sufficient fluid, a number of biological systems simply stop operating, including circulatory failure, and can lead to death. In fact, on a global scale, overheating contributes to more temperature-related deaths than being too cold.
Sensitive populations, such as children, older adults, and those with existing health conditions are particularly at risk in times of excessive heat. In pregnant women, whose body temperature is already naturally elevated, excess heat has been linked to lower birth weight in babies. Levels of air pollution are typically higher in densely populated, hot places, causing asthma attacks, allergies and other respiratory problems.
 Liddell, C. and Guiney, C., (2014) ‘Living in a cold and damp home: frameworks for understanding impacts on mental well-being’, Public Health, 11 November 2014, University of Ulster, Coleraine.