When Rebecca Fitch cuts the grass with her riding lawnmower, she makes an unusual pit stop. Every few passes she pulls up to a branch draped with a hose and sprays herself until she's soaked. Then she continues cutting the grass. “If I soak myself two or three times during the process, I have enough strength to get off the lawnmower,” says Fitch, who lives in Cleveland, known for its steamy summers. The reason? She has multiple sclerosis (MS).
Like most people with the disease, Fitch's immune system attacks the fatty coating of myelin that surrounds her nerve fibers, which disrupts nerve transmission. Myelin often regenerates, but not completely, and it tends to be thinner than normal at the site of the scar. Most of the time this doesn't matter, except when people get too warm. Heat slows down transmission in these damaged nerves, so when someone with MS experiences a rise in core body temperature due to exercise or a fever, the impaired electrical conduction in those thin patches of myelin may disrupt the flow enough to cause problems such as temporary muscle weakness, fatigue, and vision loss.
That's what happens to Fitch when she gets too warm. “I lose strength and can't move my legs,” she says. “I drag my feet and have trouble walking, and I can't get my feet into the car. I keep a coat hanger in the car, and if my legs aren't working, I slip the hanger under my feet and pull them into the car. It's better than sitting there feeling sorry for myself.”
The summer humidity makes it hard for her body to dissipate heat through the evaporation of sweat, but Fitch has trouble in winter too. She can walk from her car into the supermarket with no problem and shop for 15 minutes or so, but as she warms up, her legs get weak.
“I have to sit down,” Fitch says. “I've found good places to sit—in the dog food section, for example, where they keep those 25-pound bags of dog food. After a few minutes of cooling down, I gain a little strength and can walk down another aisle.”
Pseudo Flare-Ups
Symptoms related to overheating may make people feel like the immune system is attacking the nerves again, causing a recurrence or exacerbation of the disease, but that's not the case. The nerves are malfunctioning because of the heat, not because of any progression of the disease, according to Robert J. Fox, MD, FAAN, a neurologist at the Cleveland Clinic. “I tell my patients, ‘If you like to go in the hot tub, go in the hot tub. If you get transient weakness or numbness, that's fine,’” says Dr. Fox. “You just may have a temporary increase in symptoms.”
Most of the time these symptoms disappear when patients cool off, “but every once in a while a symptom does not go away, so a pseudoexacerbation can turn out to be a real one,” says David H. Mattson, MD, PhD, FAAN, director of the Indiana University Multiple Sclerosis Center and professor of neurology at the Indiana University School of Medicine.
“We used to be very paranoid and tell patients to avoid overheating,” adds Dr. Mattson, “but now I tell them, ‘Everything in moderation.’”
Smart Ways to Keep Cool
If heat-related symptoms are bothersome, the easiest thing to do is to avoid getting too hot, which may include staying out of hot tubs, exercising during cooler hours, staying inside and using air conditioning on hot days, taking tepid showers, and preventing dehydration. At the first sign of a fever, take an analgesic such as acetaminophen, ibuprofen, or aspirin to bring your temperature down to normal.
Fitch has experimented with several novel ways of keeping cool. “I used to work in catering, and I'd do golf outings where I'd grill steaks,” she says. “To handle the heat from the grill, I would soak a towel in ice water and drape it around my neck. I also used to spray myself with a misting bottle.”
She recently acquired an attachment for the garden hose that produces an extremely fine mist. When she sits on her patio, she wraps the hose around the sun umbrella and stays under that misty cloud. “That fine mist really helps,” she says.
Cooling garments such as vests, collars, and wristbands are also helpful, says Peter Damiri, program director of the Multiple Sclerosis Association of America. The garments contain ice or gel packs or use evaporation. One type of vest, which requires a prescription, has a pump that circulates water through tubes and lowers the body's core temperature by as much as one degree. “The doctor specifies how often the patient can wear the vest, and for how long,” says Damiri. “Usually it's no more than three times a day for 30 minutes.”
Evaporation garments, including bandannas, skullcaps, and vests, are soaked with water, which cools the body as it evaporates, although on days with high humidity these items don't work quite as well.
“These products enable people with MS to go to a family picnic or outing during the summer or on a hot day,” Damiri says. “One woman said she can cook dinner for her husband when she's wearing a cooling garment. Otherwise, the heat of the kitchen would prevent her from doing that. The cooling devices help improve quality of life.”
(A version of this article was first published in the May/June 2007 issue of Brain & Life.)
