What’s Heat Intolerance? An Explanation

Just because we’re in the cooler half of the year doesn’t mean you can’t deal with heat intolerance! (Plus, if you’re in the southern hemisphere, you’re heading into summer.) Heat intolerance is an incredibly annoying symptom of multiple illnesses and conditions, including one of POTS, one of my illnesses. But what’s heat intolerance exactly, any way? In this post, I’m going to explain what it is in general, what my symptoms of it are, strategies for dealing with it, and my favorite products for dealing with it.

Reminder that I am not a doctor or a medical professional. I’m sharing my experience and advice, and I include my sources when appropriate. Additionally, this post contains affiliate links. Thank you for supporting Kate the (Almost) Great!

What’s Heat Intolerance?

While the phrase “heat intolerance” is pretty self-explanatory, it’s still kind of hard to explain. MedlinePlus says, “Heat intolerance is a feeling of being overheated when the temperature around you rises. It can often cause heavy sweating” (x). It’s definitely not the same as not liking heat! Additionally, Heathline explains that heat intolerance is also known as “hypersensitivity to heat” (x).

So why does this happen? “When you have heat intolerance, it’s often because your body isn’t regulating its temperature properly,” Healthline says (x). Regulating your body temperature is super important! It’s something the body does to keep you going. “Your body regulates its temperature by maintaining a delicate balance between hot and cold,” so while someone might have heat intolerance, someone else might have cold intolerance (x). And some people experience both!

I’m not a scientist or a doctor, so I’ll let Healthline explain. They say, “the hypothalamus is a part of the brain that regulates your body’s temperature. When you get too hot, your hypothalamus sends a signal through your nerves to your skin, telling it to increase sweat production. When sweat evaporates off of your skin, it cools your body down” (x). So people with heat intolerance like me often sweat a lot because the body is trying to manage the heat.

While there’s little official documentation about POTS and heat intolerance, many people with it experience it. Heat intolerance in this case mainly means POTS symptoms get worse in the heat, as often POTS symptoms are symptoms of heat intolerance. Some ways that this might be demonstrated include:

Feeling faint – In my experience, I feel dizzy and lightheaded. These are also the signs of what will happen if I’m not careful and don’t do things in the next section. It can range from a general feeling of being off to feeling like the world is swimming around me, as well as seeing spots.

Excessive sweating – I experience this in 2 ways. 1) Sweating easily and 2) sweating a LOT. Like I mentioned above, sweat is the body’s way of cooling down the body. So when you overheat a lot and easily, you sweat a lot and easily.

POTS and Heat Intolerance

Actually fainting – The dizziness and sweating (for me) lead to fainting. I haven’t fainted in a while, but I know that I’m very close to doing so when I start seeing spots, when my vision starts to go in general, and when the world starts to tilt.

Being nauseous and throwing up – Nausea is a huge symptom of POTS. There’s general nausea, and then there’s throwing up. Both of which are POTS symptoms. For me, frequent nausea (or more frequent, as I’m often nauseated) happens when there’s heat, as does throwing up.

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Dealing with Heat Intolerance

Understanding heat intolerance is one thing, but it’s only helpful when you know how to deal with it. Along those lines, I’m sharing my advice for dealing with heat intolerance. A lot of these things are specific to POTS, as that’s how I experience heat intolerance. So this is a great time to remind you of my disclaimer at the top of this post – I’m not a doctor! Even if you have POTS, please talk to your doctor about the best ways for you to deal with heat intolerance.

Consuming lots of salt – POTS patients know that salt helps you retain water, and water helps you deal with heat intolerance. I once asked my cardiologist what I could do to feel better than I was, and she said to eat more salt and drink more water. POTS patients are supposed to have 3-5 grams of salt a day as a minimum (compared to 1-3 for non-POTS patients total) in general, so in the summer or on hotter days in general, I aim for the 5-gram appoint as a minimum (x). I advise reading a lot of nutritional labels to figure out what foods having higher sodium contents so you can make smart salt choices, as well as finding a sodium supplement that works for you.

Drinking lots of water – POTS patients should be drinking 2 liters of water a day (x). Water in general is super important to life, of course, but it’s also a great tool for dealing with heat. The CDC says that you need to “Drink before feeling thirsty. By the time you feel thirsty, you are already behind in fluid replacement” (x). They also advise, for the average person, “When working in the heat, drink 1 cup (8 ounces) of water every 15–20 minutes” (x).

Staying in air conditioning in the heat – If you have the option, stay in air conditioning. If you don’t have central air, try to get a window unit. On the worst days, I stay inside in air conditioning as much as possible. I love air conditioning!

Carrying a portable fan – One thing that has made my life so much better is carrying a portable fan. Back in a world where I went to an office to work, my commute involved walking up a hill, and my body temperature went out of wack and it took a while for me to cool down, even though my office has air conditioning.

Using compression gear – This is another thing that POTS specialists advise. Dysautonomia International says, “Compression support hose and abdominal binders can be helpful for some POTS patients by lessening the peripheral venous pooling and hypotension” (x). I have over-the-knee compression socks that I wear, especially on hot days, and they have the benefit of helping swelling in my joints, too. 

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My Favorite Products for Managing Heat Intolerance

Now that I’ve talked about different ways to deal with heat intolerance, here are the things I use to do so.

Once again – I’m not a doctor! But if you’re looking for things that I personally find helpful, keep reading.

Sodium supplements – Taking sodium supplements makes me not worry too much about counting how many grams of sodium I’m consuming in my food. It’s very helpful! These are my favorite ones, and they have an entire gram of sodium in a single tablet.

Water bottles – It’s much easier to drink lots of water when you have a water bottle to keep you going! This half-gallon water bottle has motivational marks with times to drink, as well as a straw, and it comes in 15 color combinations. This 32 oz water bottle also has times to drink and has 5 color options. And, of course, there’s the classic Nalgene water bottle, which comes in at least 25 color options.

Portable fan – VersionTECH makes my absolute favorite rechargeable portable fan. I can’t recommend it enough! I own 2. The battery on the fan lasts for a really long time.

Compression socks – My favorite compression socks are made by SUGIFT, and they go up to the knee. But I also advise figuring out what type of compression gear works best for you personally – over the knee socks, up to the knee socks, ankle socks, just calves, etc. We’re all different, and in addition to preferring one type over another, our bodies prefer one type over another.

How do you deal with heat intolerance?

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