Deaths in New Hampshire and two other New England states rose by 5 percent and hospital emergency visits rose by 7.5 percent during hot weather spells that seem likely to increase in frequency.

The results come from a study published this week in the journal Environmental Research, and is part of a push to have people in New England states take the health effects of heat more seriously.

“New Hampshire residents are not as used to heat as individuals are in other states. We need to make sure people take heat events seriously and take precautions to prevent illness,” said Lisa Morris, Public Health Director at the New Hampshire Department of Health and Human Services.

The study says hospital emergency department visits and deaths in Maine, New Hampshire and Rhode Island increased by 7.5 percent and 5.1 percent, respectively, on days when the heat index reached 95 degrees,  as compared to days with a maximum heat index of 75 degrees.

Heat index is a combined measure of heat and humidity that reflects what the weather feels like – roughly the hot weather equivalent of the “wind chill” index in cold weather.

Nationally, more people die during bouts of extreme heat than from any other type of weather event.

“This study will greatly help us target our outreach efforts on such days, including public outreach to inform the most vulnerable populations, such as seniors, young children, and people with chronic health conditions,” said Dr. Benjamin Chan, New Hampshire State Epidemiologist.

In New Hampshire, the heat index reaches 95 degrees between two and 10 days each summer. Climate Solutions New England at the University of New Hampshire predicts that by 2070 the number of such days will increase by approximately 12 days in Northern New Hampshire and 22 days in Southern New Hampshire.

In December 2016, the National Weather Service (NWS) Northeast Region changed its policy on when to issue an official heat advisory. NWS forecast offices in the region will issue heat advisories when the heat index is forecast to reach 95 degrees on two or more consecutive days or 100 on any single day. The previous NWS regional threshold was a maximum daily heat index of 100.

“It is expected that this change will alert people sooner to impending heat threats and, if acted upon, reduce the number of emergency department visits,” said John Guiney, Chief of the Eastern Regional Headquarters, NWS.

In New Hampshire, the results of the study and the NWS policy change are driving public health officials to revise local heat response plans.

The study shows that in addition to an increase in emergency department visits and deaths for all causes, people with pre-existing health conditions, such as asthma, heart disease, and kidney disease, fare much worse on days when the heat index reaches 95 degrees as compared with cooler days.

Data on the number of people with air conditioning in their homes in New Hampshire is limited, so a question was recently added to the statewide Behavioral Risk Factor Surveillance Survey to address this data gap. Neighboring states such as Maine report a rate of air conditioning in peoples’ homes of only 50 percent as of 2013.

The study, Heat-Related Morbidity and Mortality in New England: Evidence for Local Policy, was led by Gregory Wellenius of the Brown University School of Public Health, and co-authored by Kathleen Bush and Dennis Holt of the New Hampshire Environmental Tracking Program, along with colleagues from the state public health agencies in Maine and Rhode Island.