Understanding Uhthoff's Phenomenon

Why Staying Cool Matters for MS: Managing Symptoms During Heat Waves

If you’re living with Multiple Sclerosis (MS), you may notice that heat makes everything harder. A short walk on a warm afternoon might leave you unusually tired or unsteady. Even light housework can feel draining if the temperature climbs.

This temporary worsening of symptoms is known as Uhthoff’s phenomenon. When your body temperature rises—even by just a degree or two—nerve signals slow down, which can make MS and other demyelinating conditions symptoms like fatigue, weakness, or blurred vision more noticeable. It can even cause changes in cognition and bladder sensitivity. It’s not a relapse, and it doesn’t mean your condition is worsening. But it does make everyday tasks more difficult.

Fortunately, there are practical ways to manage it—and those strategies often work best when they’re built right into your home and daily routine.

Cooling Strategies That Fit Real Life

The key to managing heat sensitivity is prevention. Instead of reacting once symptoms show up, you can plan ahead to reduce the chance of overheating in the first place.

Start by thinking about timing. When possible, shift physical activity—like walks, home exercises, or errands—to the cooler parts of the day. Early mornings and evenings are usually safest, especially during a heat wave. If it’s hot by 10 a.m., even a simple task like vacuuming can become exhausting. Shifting your schedule can help you conserve energy and feel steadier throughout the day.

Your home environment also matters.  If you are a city dweller experiencing a recent eastern seaboard heatwave and have a demlyelinating condition, it is important to stay inside in air-conditioning as much as possible. (Here is an interesting story on the heat island effect if you are interested). On especially hot days, consider taking breaks in the coolest room of your house or spending time in air-conditioned public spaces like libraries or community centers. Take advantage of one of NYC's many cooling centers if you don't have access to reliable air-conditioning during a heat wave.  (But plan your trip carefully to avoid exacerbation of symptoms en route!) There are also some city programs available to help make air-conditioning more affordable for qualifying New Yorkers. 

Personal cooling devices—like neck wraps, cooling vests, or even a cold washcloth on your wrists—can offer extra support. There are a variety of items on the market at a range of prices points. (In effort to avoid any conflict on interest I do not use affiliate links).  A few sites that have a broad range of items can be found here, here, or here.  Multiple Sclerosis Association of America offers a cooling distribution program although there is an income eligibility requirement.  Research doesn't really support one kind of cooling product over another, so try a few and use whatever works best for you.

Another important approach is pacing. Fatigue tends to build faster in the heat, so spacing out your activities throughout the day is key. Try breaking tasks into smaller pieces, and give yourself permission to rest in between. It’s not about doing less—it’s about doing things smarter, with your energy and comfort in mind.

Finally, don’t overlook hydration. Even mild dehydration can make heat intolerance worse. Keeping a bottle of cool water nearby and drinking throughout the day can support both temperature regulation and energy levels.

Why This Matters for Therapy

As physical therapists, we know that consistency matters in recovery and maintenance. But in the summer months, staying consistent requires extra planning. Finding strategies that work for you is critical so you can continue to get  the exercise you need to stay strong, even in the summer.  In-home can be ideal for some individuals for this reason. Therapy  can help you build strategies that work in your actual space, during the times that suit your schedule and comfort level without requiring travel during a heatwave.

Therapy can help you adapt exercises to avoid overheating, recommend practical cooling options, and break down daily tasks to make them more manageable during hot weather. You don’t need to stop moving—you just need the right approach to do it safely.

If heat is making your MS symptoms harder to manage,  reach out. I can work with you to create a plan that keeps you moving, safely and confidently, no matter the temperature outside.