Florida heat can turn up the “background noise” of multiple sclerosis. Image by Daria Mironova/WMNF News
Tampa neurologist Dr. Mark Cascione explains why even a small rise in body temperature can temporarily revive old symptoms and how people with MS can prepare for a hot day outside.
For most families, a child’s soccer game is an ordinary weekend outing. For a person living with multiple sclerosis, sitting in sun-soaked bleachers can also become a test of how well the nervous system handles Florida’s heat and humidity.
Why heat makes MS symptoms worse
Dr. Mark Cascione uses that familiar scene to explain a problem many people with MS experience. As the body warms above its usual core temperature, communication between the brain, spinal cord, and the rest of the body can slow. Along nerve pathways already damaged by MS, that slowdown may be worse.
A person at the soccer field might suddenly notice an old symptom returning – a blurry eye, an unsteady leg, tingling, or weakness. Dr. Cascione’s first instruction is simple: “Get out of the heat, get out of the heat, get out of the heat, get out of the heat.”
The following steps are to move into air conditioning or shade, drink cold water, and begin cooling the body, he said. An ice or cold wrap around the neck, a portable neck fan, or even ice poured over the head can help lower core temperature. The symptoms may not disappear immediately, but cooling is the essential first step.
Dr.Cascione, who is leading the new MS and Neuromuscular Center of Excellence in Lutz, describes the effect in terms of the physics of nerve transmission. The body’s nervous system functions best near its normal temperature. Once that temperature rises, signals take longer to travel from “point A in the brain to point B,” such as an arm or leg. In areas affected by prior MS attacks, heat can further disrupt already compromised signaling. In some cases, he said, the nerve bundles may temporarily fail to communicate effectively with an arm, leg, eye, or bladder.
When old symptoms return
That does not require an extreme outdoor temperature. A sauna, steam bath, fever, or other change that raises core temperature may be enough.
Dr. Cascione said some women also notice old symptoms during their menstrual cycle, when body temperature can rise slightly. Once the body cools, those symptoms typically settle back toward the person’s usual baseline.
The connection between heat and MS has been recognized for generations. Dr.Cascione recalled that in the 1800s and earlier, physicians sometimes placed people suspected of having MS in hot water and used the resulting weakness or paralysis as evidence supporting a diagnosis. He described the practice as archaic and cruel but said its history describes how dramatically heat can interfere with damaged nerve pathways – even when the first damage occurred decades ago.
To help patients understand these fluctuations, Dr.Cascione compares MS symptoms to background noise on a radio. Each person has a different pattern: numbness for one, tingling for another, balance problems, blurred vision, or double vision for someone else.
“Sometimes the noise on the radio gets louder, sometimes the noise on the radio gets softer,” he said. “But you can make the noise louder by overheating yourself.”
How to cool down safely.
The distinction between a temporary heat-related flare and a problem that needs medical attention often comes down to time and familiarity. If cooling brings a person back toward baseline, especially when the symptom is one they have experienced before, heat may have temporarily aggravated an old pathway. If symptoms continue for several hours or persist into the next day, Dr.Cascione advises contacting a healthcare provider.
New, severe, or concerning symptoms also warrant medical attention.
Preparing for Florida heat
Preparation can prevent the soccer game scenario from becoming an emergency. Dr. Mark Cascione recommends bringing ice water or other cold beverages, wearing cooling wraps, and using a small fan around the neck. Just as important, patients and caregivers should recognize their personal warning signs before symptoms become overwhelming.
That education should not be a one-time conversation, he said. In South Tampa, Cascione used to hold seasonal “Lunch and Learn” sessions. The discussions paired summer heat precautions with hurricane planning, including what people with MS should do if a storm knocks out electricity and air conditioning.
He believes those lessons should be repeated regularly, particularly in a region where high heat can last for months.
Dr. Cascione’s path to neurology
Dr.Cascione’s interest in neurology began far from Florida. He entered medical school expecting to pursue cardiology. Still, during his basic science training, he became fascinated by the nervous system and how the brain and spinal cord govern the body.
What began as a professional interest became personal, Dr. Cascione said, not because a family member had MS, but because of what he learned from his patients over the years of caring for them.
Many now travel from Sarasota, Bradenton, and Fort Myers. When he moved his practice north to Lutz, he worried the longer drive might cause patients to leave. Instead, he said, nearly all chose to follow him.
That loyalty reflects the part of medicine he values most – the ability to help others.