Summary: Rising heat and more frequent extreme temperatures driven by global warming are expected to harm public health and reduce productivity. Experts warn that people with temperature-sensitive conditions, particularly multiple sclerosis (MS), face increased risks because heat reliably worsens their symptoms.
Source: Cedars Sinai Hospital
Climate-driven temperature increases threaten worker productivity worldwide, says Nancy Sicotte, MD, chair of the Department of Neurology at Cedars-Sinai.
“There is an optimal temperature range in which the brain and body perform best,” Sicotte explains. “When temperatures rise beyond that range, cognitive speed and physical performance decline, and overall productivity falls because neither our brains nor our bodies can operate at full capacity.”
Sicotte references a 2019 International Labour Organization report that assessed how heat stress from climate change affects labor and economic output. That analysis forecasts reductions in effective working hours as extreme heat and weather events become more common, with the heaviest impacts on outdoor and manual labor sectors like agriculture and construction.
Beyond lost work hours, Sicotte emphasizes how shifting seasonal patterns and more unpredictable weather are already forcing people in climate-dependent professions to alter long-standing practices. “Farmers are changing their behavior because seasons no longer follow historical patterns,” she says. “This growing unpredictability is difficult to quantify and creates long-term uncertainty for communities that depend on stable seasonal cycles.”
People who have difficulty regulating body temperature—young children, older adults, and those with certain medical conditions—are particularly vulnerable to the health effects of heat waves and sudden temperature swings. In addition, extreme weather events such as hurricanes can disrupt medical services and limit access to lifesaving care for patients with chronic illnesses who require regular treatments.
One group of patients at special risk are people with neurological disorders that are sensitive to body temperature changes. Multiple sclerosis, an autoimmune disease in which the body damages the protective myelin sheaths around nerve fibers in the brain and spinal cord, is especially affected by heat.
“There’s a very clear correlation between heat and worsening symptoms of MS,” Sicotte said.
This relationship is known clinically as Uhthoff’s phenomenon: when body temperature rises—due to fever, intense exercise, or simply a hot day—people with certain neurological conditions can experience temporary aggravation of symptoms. For MS patients, that can mean increased weakness, numbness, tingling, balance problems, fatigue, or transient vision disturbances.
As global warming increases the frequency of hot days, those living with MS may face more frequent symptom flare-ups that limit daily activities and quality of life. Sicotte expresses concern that climate trends could undermine the medical progress of the last two decades, which has dramatically improved diagnosis and treatment options for MS.
When Sicotte began practicing, the medical community had far fewer tools to diagnose and manage MS. Treatment options were limited, and many misconceptions persisted, such as assumptions that pregnancy would worsen MS—a view that led some women to avoid childbearing. Advances in imaging, earlier diagnosis, and more effective therapies have since transformed care. Today, clinicians can sometimes identify disease activity before severe symptoms arise and offer medications that reduce relapses and preserve function. Women with MS now have better information about pregnancy and family planning that allows them to make informed choices.
These improvements have created a generation of patients who can manage MS while working, parenting, and maintaining active social lives. Still, Sicotte worries that rising temperatures—especially in temperate regions that often lack widespread air conditioning, such as some coastal areas of southern California—will produce more symptom-limiting days for many of her patients.
“I have patients who travel to colder climates and report feeling dramatically better,” she notes. “The prospect that people might need to relocate because of worsening heat sensitivity from MS would be deeply disruptive.”
There are practical strategies and aids that can help. Many utility companies offer reduced rates or assistance programs for customers with qualifying medical needs, which can make cooling and heating more affordable. Devices like cooling scarves, vests, and cold-water immersion or cooling baths are commonly used by people with MS to manage heat-sensitive symptoms. Clinicians increasingly discuss heat-related symptom management with patients and recommend individualized coping plans.
Still, Sicotte stresses that individual health is intimately connected to planetary health. “Long-term wellbeing for patients depends on addressing the broader environmental changes that are driving more extreme heat and weather. If the planet’s climate continues to deteriorate, the health consequences for vulnerable populations will only grow.”
Neuroscience News would like to thank Sarah R. Lichtman for submitting this article for inclusion on the website.
Source:
Cedars Sinai Hospital
Media Contacts:
Sarah R. Lichtman – Cedars Sinai Hospital
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