A heat wave can become dangerous long before someone feels seriously ill, and that is particularly important for older adults to understand. Here is what you need to know about heat-wave safety for older adults and what regular habits can increase exposure. During prolonged hot weather, keeping water readily available and drinking regularly can be easier than trying to catch up after spending hours without fluids. Pay attention to the heat index as well as the temperature because humidity affects how hot conditions actually feel. Older adults living alone deserve particular attention during heat waves because there may be nobody nearby to notice that their behavior or physical condition has changed.