Temperature and heat index data was analyzed in linking hospital emergency admissions data to determine if extreme high apparent temperatures are associated with significant increases in hospital admissions. Some health outcomes studied included cardiovascular, respiratory, kidney problems and birth defects. Significant increases in cardiovascular disease and respiratory health admissions were observed in New York City when apparent temperatures increased above 31.7°C (89°F) and 35.6°C (96°F) respectively. A study of congenital birth defects in New York State found that congenital cataracts increased significantly when heat waves lasted more than 3 days (Universal Apparent Temperature > 32°C (90°F)). Multiple New York State studies also found that the minimum or night time temperature was the most sensitive indicator for impacts of extreme heat on health. This supports the assertions that warmer nighttime temperatures contribute to health problems due to the inability to cool from daytime heat.
One study in New England determined that a significant increase in emergency department visits due to all health issues occurred with an apparent temperature of 35°C (95°F). Lag times during and after extreme events and increases in health issues will be discussed as well as distinguishing the importance of nighttime apparent temperatures versus daytime apparent temperatures and their effect on health issues and mortality. Based on these studies, New York and New England are considering lowering the heat advisory threshold for all of New York and New England to the New York City criteria of 2 consecutive days of 35°C (95°F) beginning the summer of 2017. Specific statistics for each type of health issue will be described as well as warning and safety information in development through collaboration between state and federal agencies and universities.