islands affect global climate by impacting the jet stream. Several studies have revealed increases in the severity of the effect of heat islands with the progress of climate change. Health effects UHIs have the potential to directly influence the health and welfare of urban residents. Within the United States alone, an average of 1,000 people die each year due to extreme heat. As UHIs are characterized by increased temperature, they can potentially increase the magnitude and duration of heat waves within cities. Research has found that the mortality rate during a heat wave increases exponentially with the maximum temperature, an effect that is exacerbated by the UHI. The number of individuals exposed to extreme temperatures is increased by the UHI-induced warming. The nighttime effect of UHIs can be particularly harmful during a heat wave, as it deprives urban residents of the cool relief found in rural areas during the night. Research in the United States suggests that the relationship between extreme temperature and mortality varies by location. Heat is more likely to increase the risk of mortality in cities in the northern part of the country than in the southern regions of the country. For example, when Chicago, Denver, or New York City experience unusually hot summertime temperatures, elevated levels of illness and death are predicted. In contrast, parts of the country that are mild to hot year-round have a lower public health risk from excessive heat. Research shows that residents of southern cities, such as Miami, Tampa, Los Angeles, and Phoenix, tend to be acclimated to hot weather conditions and therefore less vulnerable to heat related deaths. However, as a whole, people in the United States appear to be adapting to hotter temperatures further north each decade, although this might be due to better infrastructure, more modern building design, and better public awareness. Increased temperatures have been reported to cause heat stroke, heat exhaustion, heat syncope, and heat cramps. Some studies have also looked at how severe heat stroke can lead to permanent damage to organ systems. This damage can increase the risk of early mortality because the damage can cause severe impairment in organ function. Other complications of heat stroke include respiratory distress syndrome in adults and disseminated intravascular coagulation. Some researchers have noted that any compromise to the human body's ability to thermoregulate would in theory increase risk of mortality. This includes illnesses that may affect a