MS & Heat Sensitivity: Uhthoff’s Phenomenon

According to Healthline:

Some people with multiple sclerosis (MS) can feel their symptoms worsen when they become overheated. When elevated body temperature impairs vision, it’s called Uhthoff’s phenomenon. Uhthoff’s occurs because of damage to the optic nerve, which interferes with the transmission of signals between the eye and the brain. Symptoms include blurry or reduced vision.

Uhthoff’s phenomenon is often one of the first signs of MS. Sometimes called “Uhthoff’s syndrome” or “Uhthoff’s sign,” the condition is named for William Uhthoff (1853-1927), a German professor of ophthalmology.

Although I have been fortunate enough to avoid many of the vision problems that can stem from having Multiple Sclerosis – I DID manage to tick this box off.  I first began noticing something was wrong when I was at the gym working out.  I would arrive, seeing things JUST FINE.  If you were to walk up to me as I frantically peddled myself to NOWHERE on the elliptical trainer in the first 5-10 minutes, I would greet you with a hardy hello and ask about the family or work or whatever it was that we have in common.  Just like any other time that we have run into one another….

BUT…if you were to approach me AFTER those first few moments…I would still greet you with a huge hello – followed by an awkward silence OR a lame inquiry about some general topic in the hopes that YOUR response would clue me in to who the fuck I am talking too.  Because, as I stand tall on the machine trying to go faster and faster or achieve some crazy “interval training” course, I start sweating and my body temperature starts to rise.  AND in direct correlation, my vision goes to shit!  Not just some of the time, but EVERY TIME that my body begins to overheat.  Doesn’t matter WHERE or WHAT I am doing  – it is just a guaranteed in my life now.



Announcing this to friends and family, it is understandable that some might be a bit alarmed….what IF I am driving just AFTER finishing a workout? OR on a super hot day, when I have just spent the afternoon standing on the sidelines of some soccer field in the relentless summer sun?  HOW can I feel safe driving?

 Here is the deal.  FIRST: the MINUTE my body temperature goes back down, my vision comes back.  SO cranking the A/C does wonders.  BUT more importantly EVEN if I HAVE to drive BEFORE this happens, I can still SEE things, just not specific features or details.  SO if I were at a stoplight and someone were crossing the street, I can’t tell if it is YOU, my 18 yr old son or an 80 year old lady BUT, I  do know that SOMEONE is indeed crossing the street.

So have no fear people – NOT going to be plowing down grandma anytime soon.

Of course, as with any other “wonderful” symptoms that comes with this “fantastical” disease – whether it be falling down or constipation & bowel dysfunctions, falling asleep on the potty, or issues with sex ….I have stories.

I figured I would share one of my”hot moment” favorites:

It is a sunny summer day in the beautiful Pacific Northwest.  The kids and I had packed up and headed out fairly early in the morning to spend the day with a good friend and his kids at their pool club.  Although I have just made it perfectly clear that doing anything that raises my body temperature messes up my vision (and heightens any other symptoms I am experiencing) this does NOT mean that I will turn down the opportunity to lounge poolside, soaking up the VITAMIN D and working on a tan.

As we sat, chatting away, catching each other up on all the news in our lives, a head popped up on the side of the pool about 10 feet from where I lay.  Being the EVER diligent mom, I was keeping a constant eye on the kids while they frolicked away. (Ok, maybe NOT frolicked, cause I am pretty damn sure NONE of them have EVER frolicked but goofing off and taking turns pushing each other into the pool.)

So a head pops up and I hear “momma, can you throw me the goggles?”  Without missing a beat in our conversation, I quickly reached into the side pocket of the enormous bag that I had schlepped in, pulled out one of the dozen pairs of goggles that we seem to have amassed (I fear that there MIGHT have been a bit of thievery going on at some point because I sure as hell don’t remember BUYING that many pairs) and flung them at the bobbing head at the side of the pool.  Job well done by the EVER attentive momma….

Until my friend leans over and says “honey, why did you do that?”  My response was “because Piper wanted a pair of goggles.”  (That being my then 8 yr old BLONDE haired DAUGHTER.)  To which he responded….”OK…..but you DO know that you just gave a little BLACK BOY your goggles….?”


The good news is that the little boy DID bring them back to me later in the day, AND was super polite and thanked me for sharing:)  Yet another “life lesson” for the kids –

“Always SHARE….even if you don’t know WHO THE FUCK you are sharing with.”




Although I wrote this post last week, as I was working on finalizing it to go live, I ran across some NEW information pertaining to Uhthoff’s phenomenon…which has led me to be completely SURPRISED and once again thinking….



According to VERY in an article b

(Updated May 06, 2016)

The Uhthoff phenomenon is a unique sign in multiple sclerosis characterized by a worsening of one or more MS symptoms when the body’s core temperature is elevated…In the Uhthoff phenomenon, scientists believe that heat worsens these already damaged nerve cells pathways, which exacerbates current MS symptoms. 

And here, all this time, I thought that the term Uhthoff’s phenomenon pertained to ONLY my vision problems when I am hot.  It’s what my doctor told me.  But according to this, it is actually referring to my sensitivity to heat and ALL of my symptoms worsening.  As I mentioned earlier in this post, my other symptoms DO get worse but I never knew that long long ago, this German professor’s discovery was addressing ALL my heat issues and not just my sight.



I guess you learn new shit all the time….it’s a process:)




6 Replies to “MS & Heat Sensitivity: Uhthoff’s Phenomenon”

  1. It is not the heat do much that wraps me up as it is the humidity! I just lose my energy. I head for the air conditioning. We get a lot of it in the Ottawa area during the summer. I will take the dry heat in Arizona anytime.

    1. Hey Bruce!
      Can completely empathize about humidity. Having grown up on the East coast (and now visiting my folks back there every summer) I know it all too well. Although I must confess that when we do go now, I pretty much live at the beach and in the water to battle getting over heated. And to think that I used to head out almost daily for 6+ mile runs while there. Can NOT even imagine that at this point.

      I know that for others it is the COLD weather that causes issues. I have to say that even with the vision tanking and other symptoms cranking up, I would take feeling hot over being cold any day of the week. But that is more because I have NEVER liked feeling cold irrelevant of the MS shit:)

      Thanks for taking the time to read and share!

      Meg (aka BBH)

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