As a heatwave grips the U.S., a look at how extreme heat affects the body
As heatwaves sweep the country, NPR's A Martinez asks W. Larry Kenney, professor of physiology and kinesiology at Penn State University, how extreme heat affects humans.
As heatwaves sweep the country, NPR's A Martinez asks W. Larry Kenney, professor of physiology and kinesiology at Penn State University, how extreme h
Read Full Story at NPR Health →Why This Matters
The human body’s response to extreme heat reveals deeper vulnerabilities in public health infrastructure, particularly as climate change intensifies seasonal patterns. With record-breaking temperatures becoming routine, the physiological strain on vulnerable populations—such as outdoor workers, elderly individuals, and those without access to cooling—underscores the urgent need for adaptive policies beyond emergency warnings.
Background Context
Heatwaves have historically been the deadliest natural disasters in the U.S., outpacing hurricanes and floods in mortality rates, yet they receive far less sustained attention or funding for prevention. Research shows that marginalized communities, including low-income neighborhoods with limited green space or air conditioning, face disproportionate risks due to systemic inequities in urban planning and healthcare access.
What Happens Next
As heatwaves expand in duration and geographic reach, cities may accelerate investments in heat-resilient infrastructure, such as expanded cooling centers and reflective building materials. Meanwhile, employers in high-risk industries—like agriculture and construction—will face mounting pressure to adjust work hours or provide protective measures, testing the balance between economic productivity and worker safety.
Bigger Picture
This summer’s heat crisis is a microcosm of a global trend: rising temperatures are not just an environmental issue but a cascading threat to labor productivity, healthcare systems, and social equity. Policymakers and scientists are increasingly framing extreme heat as a "silent crisis," one that demands cross-sector collaboration to mitigate long-term damage to both human health and economic stability.
