yellow, orange, and red waves of color with a humidity symbol

The Hell of Humidity

Talking about the effects that increased temperatures have on those of us with Multiple Sclerosis is something I’ve done many, many times (see here, here, and here).

Increased humidity

Discussions of the effects of warmer weather are common in publications geared towards MS. However, one aspect of this weather that I feel doesn’t get its due is the effects of increased humidity. As we have been going through a period of intense humidity where I live in the mid-Atlantic United States, this seems like as good a time as any to talk about it. Increased humidity can be extremely devastating to someone with MS, even when the ambient temperature is fairly mild. Increased humidity alone is enough to raise our body temperatures and bring about a rapid worsening of symptoms.

MS and increased temps

As mentioned many times in previous articles, an increase in body temperature for someone with MS can bring about a temporary worsening of symptoms. Increased temperature affects the speed at which signals on our damaged nerves travel. So the more myelin you’ve had damaged or eaten away by your immune system, the worse you will be in the heat. Areas that may be damaged, but not enough to be a problem, suddenly become problem areas when the temperature rises. When my body temp increases, I have trouble walking, I slur my speech, my right arm becomes numb, and my vision blurs. I start revisiting the symptoms of the many exacerbations I’ve had over the years.

Humidity and evaporative cooling

So what makes humidity such a problem? Most people know that the more humid it is, the warmer they feel. We even have the “Heat Index”, which is a chart that takes the temperature and relative humidity and figures out what the temperature actually feels like to us. So higher humidity makes us feel warmer, but why? Without trying to get too sciencey, it’s because it affects our body’s ability to cool itself. One of the key ways the human body helps regulate its temperature is through sweating. It does this through the process of evaporative cooling (you may see cooling towels and other products that advertise themselves as working through evaporative cooling, our bodies come with this handy feature built in). In a very basic explanation, evaporative cooling works like this: liquid changes into a gas (vapor) by shedding molecules into the air, those molecules draw heat from the hotter air, cooling them down as the liquid and air find an equilibrium; this also cools the surface where the liquid was, because the hotter molecules of that liquid are more likely to escape into the air and become vapor first. When humans sweat, our bodies are taking advantage of this process. A liquid (sweat) comes out onto our skin, evaporates and that process of the sweat becoming vapor cools us down.

When sweating no longer cools us down

Here is where humidity becomes a problem. Humidity is essentially the amount of water vapor in the air: the higher the humidity, the more of that water vapor is present. The more water vapor already in the air, the less it can accept through evaporation. This means that we can sweat and sweat but because there is already so much moisture in the air, it can’t evaporate and so the process of sweating no longer cools us down. So the higher the humidity, the worse our body is at being able to cool itself and regulate its own temperature.

Be aware

It can be hard to battle humidity, so it’s important to be aware of it. Recognize and inform your friends and family that it’s not only warm temperatures that you need to be wary of, but high humidity as well. If you experience a temporary worsening of symptoms, try not to panic, but understand that you need to cool off. Ice packs and a cold shower are often very helpful.  However take note, there are a lot of cooling devices that work through ”evaporative cooling” (many are towels you soak and then put around your neck). Those products won’t be very effective when the humidity is high, for all the same reasons that your sweating isn’t effective. It’s not that the products are defective, it’s that they don’t do a great job explaining when they will and won’t work.

Thanks for reading!

Devin

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Comments

View Comments (34)
  • Senator
    6 months ago

    Great article Devin and very timely with the heat hitting the whole nation. Diagnosed with PPMS 8/11. I try to keep up to date on all items MS, but some items are found on your own. The heat problem with MS was just an item I accepted as just another problem to endure. I realized after my 1st full Dose of Ocrevus that I was sweating after exertion or exposed to heat. I was not sweating prior to Ocrevus, but am now, and it is helping me cope with heat and exertion. I can stay outside longer in heat, and with exertion of doing chores around house I am sweating and not near as fatigued as before. Wonder if anyone else is experiencing this ?

  • Devin Garlit moderator author
    6 months ago

    Thanks so much for sharing that Senator! I am wondering if others have experienced that on Ocrevus as well!

  • ggsmslife
    6 months ago

    Its funny (not really) that a comment was made by someone that THIS year seems to have a different effect on them, like the humidity is worse or just feeling worse, and I agree with that. Last year I could get out and do a couple things in the heat, as long as I did it the right time of day, and water, shade, etc. This year we decided to try a garden again (last couple years just didnt work out) and my son which lives minutes away came and tilled. I planted in the evening and his job was to till the weeds as they needed and I would water and pick the items. I figured I could do both of those in low light times of the day….BUT no…I dont know why its this way this year and not in a couple years prior that I can remember..I just cannot go outside when the humidity is up. I too, like one of the commentators, didnt know anything of the dew point, and didnt even keep track of humidity so much over the years. This year Im all over it. I live on the east coast and not only has the humidity been a problem this last month or so its the heat index to go along side of the unusually high temps. It was like 106 here last week, 90 degrees before 9am. That is brutal. Just to let my 2 dogs (shitzhu) out for a potty break the heat from opening the door just makes me feel awful. I have a gadget that shows me inside/outside air temp, humidity for both and a couple other things that dont come to mind and I look at it off and on all day. To watch as the temps and humidity changes, getting an understanding of heat vs heat with humidity. It is quite different. One this is for sure though-either is dangerous for us MSers! I have been researching cooling vests and such and Im seriously going to invest in one to see if it can get me out there on days when its not so brutal. Its no fun being a hermit crab, but things could be worse. I focus on the good like the birds that come to my feeders. Hummingbirds that come right up to the window for me to watch. Deer, and rabbit, even squirrels at play in the yard. It will be fall soon enough and I will certainly love those days!
    Devin, I agree with you on the evaporative vests and such. They are not very effective, I dont think, and especially with the humidity. I wanted to ask if you or anyone you know with MS (or readers here) have ever experienced a red face and upper arms and neck area (all at the same time). I can be in the house just doing something insignificant and my husband will come in and say I need to go sit down and cool off. I dont feel the symptoms he sees, but he can touch my face and it is like its on fire! If its a really bad one it can put me down for the rest of the day/night.

  • Devin Garlit moderator author
    6 months ago

    Thank you ggmslife, appreciate the comment. I haven’t had that happen with my face and arms, but I’m sure another read or two out there must have. I too feel like the humidity is much worse this year. I’d even settle for hot at this point, as long as it wasn’t humid too.

  • Shelley D.
    6 months ago

    Awesome article, Devin! Thank you for explaining why humidity wreaks havoc on so many of us. Having lived in NC and OH all my life, I’ll never forget the first time I went out west (NM, post diagnosis). It was August & in the 90s. We were outside and my friend saw that I was getting overheated. She brought me to some shade. To my amazement, I immediately started to cool off! Ever since then, I’ve proclaimed, ” I’d rather it be 90 with low humidity than 80 with it high!” For me, “It’s not the HEAT, it’s the HUMIDITY!”

  • Devin Garlit moderator author
    6 months ago

    Thanks Shelley D., I 100% agree, I’d take 90 with low humidity over 80 with high any day of the week!

  • Jan
    6 months ago

    Great article!! While heat does affect me, humidity is far, far worse. Plus the combination of high heat and humidity is very tough. I often still soldier on but it is not easy, nor is it likely too wise.

  • Devin Garlit moderator author
    6 months ago

    Thank you Jan, it can definitely be unwise to soldier on if it’s too hot and humid. Sometimes we have to know our limits, so take care!

  • JosephKarpinski
    6 months ago

    Give this a try. In the cool of the evening open all the windows all night. When the sun comes up, close everything down. In the heat of the day, our house is like 10 degrees cooler than outside. You may not think so, but 78 degrees is ice cold when it is 88 outside. Really helps…

  • Devin Garlit moderator author
    6 months ago

    Thanks for sharing JosephKarpinski!

  • Sharonbaron
    7 months ago

    I hate summer. The heat is bad in Va and it’s hard to work

  • g3o9af
    7 months ago

    Hi Devin,

    I forgot (heat-related) to mention “Comfort gel
    packs.” http://www.accurategelpacks.com

    They work!

    Donna

  • Azjackie
    7 months ago

    Humidity is horrible. Soon before I was diagnosed my friend invited me to FL in June. She’s a teacher so June it was. We were walking in St Augustine. This was my first weird thing. I was sweating more than the gallons of water I was drinking. My relief was literally pouring my last gallon over my head semi drying off and the motel A/C. I thought this was so weird. I grew up in Phx and Tucson AZ outside all the time. I was told humidity totally different than “dry” heat. Maybe but my deteriorating myelin begs to differ. I hate all heat. Showers, direct sunlight, humidity, phooee. Add this to my new symptom heavy crushing pressure in my head before a rain storm. Yippee monsoon rain season.

  • Devin Garlit moderator author
    6 months ago

    Thank you Azjackie! I think many folks had some of their first experiences with MS in humid environments. They maybe didn’t notice at the time, but I think when a lot of people think back, they can remember a time where it was humid that they didn’t feel well. Keep cool!

  • Jan
    6 months ago

    In reply to what you said, I am not one who gets emotionally down from poor weather—however I can definitely tell when rain is coming, or I should say my body can tell.

    You brought up a good memory with St. Augustine—my honeymoon was at Amelia Island back in the days prior to a mess and when I had full functionality. (I was talking into my phone right now and did not edit but only because I laughed at the reality of the goof: had intended to say MS).

  • Azjackie
    6 months ago

    Parts of AZ have great weather. Summer sucks. I’m 48 native Arizonan. 4 months temps of 95-115. I am totally a hermit. A/C is my best friend. Phoenix and South 4 months of 100-120. More humidity than the rest of the state. Jobs in Phoenix or Tucson. Northern Arizona wages are $10/hr – $20/hr. Cost of living lower. Taxes pretty even statewide. Many Phoenix workers live in Northern Arizona and commute the 2 hrs one way daily. Ick. There is really 1 main artery out of Phoenix. I’ve always lived and worked in Northern Arizona. Less traffic, cooler, sanity.

  • g3o9af
    7 months ago

    Hi AzJackle,

    I also hate all heat now and I am a Clinical Lab Technologist (cotton Lab coat… no more).

    Shouldn’t Arizona be an ideal place to relocate?

    Thx,

    Donna

  • g3o9af
    7 months ago

    Thank you Devin!

    Yes , it has effectively taken away my life from late Spring through early Fall.

    It is devastating because… well you know why

    Donna

  • MSFighter
    7 months ago

    Devin, I have mentioned before, I absolutely love reading your posts. Also, my son’s name is Devin…spelled the same… I may have already told you that. Gotta love that brain fog…anyway, Im not on here much but when I see you posted something,I always check it out. Take care and stay strong my fellow MS’er

  • Devin Garlit moderator author
    6 months ago

    Thanks so much MSFighter! Also, that’s great, I rarely see someone with my name spelled the way I do!

  • potter
    7 months ago

    A frozen water bottle on my neck does me wonders. I grab one out of my cooler when I feel like I am over heated. I carry a small cooler with me most of the time. Kansas can be hot from April to November. Potter

  • potter
    7 months ago

    We didn’t even have spring this year, the temp jumped to the 90’s. We are having high humidity this week and they said the sweat factor will be 105. I am putting off running some errands until it cools down some. It is suppose to be cooler next week, we will just have to make do with the groceries we have. Potter

  • Devin Garlit moderator author
    6 months ago

    Thanks Potter! I feel the same way, that we skipped spring. I miss those middle seasons that weren’t so extreme, they seem like a thing of the past!

  • Harleydog1
    7 months ago

    I have to take cool to cold shower. Your lucky.

  • Harleydog1
    7 months ago

    Very good. MS is terrible I fell out of my bed so many times I can’t remember. Then I read we’re a guy fell out a window. I sure hope he’s ok . This is not the club I signed for Have great day

  • bethybright
    7 months ago

    I’m obsessed with the dew point. I never even knew what a dew point was but now it’s the basic litmus for how shitty I can expect to feel on any given day. This long stretch of such extreme heat and humidity really messes with me. I start to feel really low mentally like a shut in who isn’t able to walk out the front door. It broke here last night so I took a drive with the top down. It helped. I hope we get more days like today this summer. My mental state could really use a break. 🙂

  • Kym
    7 months ago

    Humidity is hell!
    Just opening my front door this week it hit me hard.
    I had to stay in the house alot, which annoys me. But, I’d rather be comfortable than having symptoms.

    Thanks for a good post.

  • Devin Garlit moderator author
    6 months ago

    Thanks Kym, I feel like it’s be an especially harsh and humid summer!

  • CubsFan
    7 months ago

    How long was it into your diagnosis heat became a factor?

  • Devin Garlit moderator author
    7 months ago

    CubsFan, while heat was somewhat of an issue early on, it wasn’t really until about 10-13 years post diagnosis that it really started to become a severe issue for me. Everybody is a bit different though!

  • mcknighm
    7 months ago

    Thank you so much, Devin, for this article…I was diagnosed 2 years now and the heat and humidity is now affecting me.

  • CubsFan
    7 months ago

    Great, more to look forward to. I enjoy reading your articles. I don’t know anyone else really with MS so it’s helpful.

  • Kym
    7 months ago

    Heat has always been an issue for me.

  • CubsFan
    7 months ago

    I’m two years into my diagnosis and being outside in the heat doesn’t bother me. When I’m active playing a sport or something I seem to get tired after a hour or two and then when I cool off I feel better. I’m not sure if this was what happened preMS or not? Maybe I got tired before also but shrugged it off thinking nothing about it and now I’m more cautious?

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