Extreme temperatures cause thousands of preventable deaths 

Most people feel the weather change around them but rarely think about its deeper impact. Heat can strain the body before anyone notices. Cold can harm just as quickly. These forces shape human life far more than daily forecasts suggest.

A new study reveals that extreme temperatures have caused thousands of preventable deaths across the United States.

The findings appear during a time when climate shifts keep growing more intense and more unpredictable.

Extreme temperatures and deaths

Researchers at Mass General Brigham studied national mortality records covering 25 years. They wanted to learn how heat and cold shaped death patterns across the country.

The study focused on the CDC’s WONDER platform. This tool allowed the team to review death certificates listing extreme temperatures as underlying or contributing causes.

Using this method, the researchers could capture direct events rather than relying on predictions.

Study senior author Dr. Shady Abohashem noted that prior studies examined heat- and cold-related deaths separately.

“But this study provides a real, observed nationwide and contemporary assessment of deaths related to non-optimal temperatures at both ends of the spectrum and across key demographic subgroups,” said Dr. Abohashem.

The research team chose a simple goal. They wanted to understand who faces danger and how these patterns have changed over time. Their findings uncover a long arc of risk that has remained mostly unseen.

Heat and cold exposure

Between 1999 and 2024, the United States recorded more than 69 million deaths. Among these deaths, 69,256 involved exposure to extreme heat or extreme cold.

Cold accounted for 65 percent of cases. Heat accounted for the remaining 35 percent. The numbers rose in more recent years, which mirrors ongoing climate stress across many regions.

“Our findings show that both heat and cold exposure continue to claim thousands of lives every year in the United States, deaths that are largely preventable,” said Dr. Abohashem.

He added that heat-related deaths will likely rise as warming trends strengthen. The data shows how small shifts in temperature can cause serious health effects.

Many deaths occur during sudden events rather than long periods. Quick changes trap vulnerable people before they have time to respond.

The burden of extreme temperatures

The study revealed that older adults face the highest danger. People 65 and older remain more sensitive to heat stress and cold shock. Men also show higher mortality from extreme temperatures when compared with women.

Racial and ethnic disparities add another layer. Black individuals face the highest heat related adjusted mortality rates. Their cold related rates are also the highest. Whites follow next, then Hispanics.

These patterns reflect long standing inequalities. Housing conditions differ widely across communities. Some homes lack strong cooling. Others lack reliable heating. People with outdoor jobs face direct exposure.

Those with chronic conditions face greater stress during temperature swings. Health care access also plays a major role.

Climate and temperature extremes

The study arrives during a period shaped by fast climate change. Heat waves now come earlier and last longer. Cold spells may strike with sharp intensity even as average temperatures rise.

These swings stretch public health systems. They also test the limits of homes, power grids, and community support networks.

“Climate change increases risks of severe weather events, and our findings highlight the need for targeted adaptation strategies, like improving housing quality, access to cooling and heating, and early-warning systems, to protect vulnerable groups as climate extremes intensify,” said Dr. Abohashem.

Cities face heat trapped by buildings and concrete. Many areas lack shade and green cover. Rural regions face distance barriers and limited emergency support.

People living alone face delayed help during sudden events. Climate pressure reaches every corner but does not reach all with equal force.

Everyday temperature stress

Extreme temperatures affect daily life in slow, steady ways. Heat strains the heart and lungs. Cold stresses circulation and breathing. People with chronic illness feel these shifts more strongly.

Medications can change how bodies handle temperature. Young children and older adults cannot adjust as fast. Many people ignore early symptoms. By the time warning signs appear, the body may already struggle.

Regions with older housing stock face greater risk. Hot nights become dangerous when homes cannot cool down. Winter storms turn deadly when heating fails.

Power outages worsen both summer and winter risks. These events show how infrastructure shapes survival during temperature extremes.

An unequal burden

The study highlights how social structures influence health outcomes. Wealthy neighborhoods often have better insulation, safer cooling systems, and access to health services.

Low income communities face more hazards. They may lack air conditioning or rely on older systems. They may live farther from cooling centers or warming shelters.

Many work outdoors in agriculture, construction, delivery, or maintenance roles. These jobs heighten exposure.

Inequities also extend to information. Some households lack early alerts or cannot respond quickly due to mobility or financial limits.

Language barriers can block warnings. Access to transportation can shape survival during emergency conditions.

The research highlights how these social gaps determine who faces danger during temperature extremes.

Rising death toll

The findings show a clear trend. Temperature-related deaths are preventable. Climate change magnifies the risk but does not remove the possibility of protection. Communities can strengthen housing quality.

Cities can expand access to cooling and heating. Emergency systems can warn people earlier. Public communication can reach groups that often miss alerts.

The study’s long time frame offers strong evidence. It shows that risk patterns remain consistent and predictable. Knowing who faces the greatest danger allows for better planning. Public health officials can create targeted outreach.

Local leaders can support safer building practices. Community groups can help residents prepare for extreme days.

Protecting vulnerable people

Protecting vulnerable people requires steady effort, including clear communication, strong planning, and fair access to resources.

Climate change creates new pressure points, but human action can ease them. The research shows that awareness and preparation matter.

The findings invite a larger conversation about temperature safety. They show the need to consider heat and cold together rather than as separate issues. Both present real threats and shape mortality patterns.

The study is published in the journal Annals of Internal Medicine.

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