Jennie, I stay inside. Period. My MG goes so fast downhill out in the heat, that I "order in" whenever possible. So many places have free shipping that it hardly seems worth it to go out. Groceries too!

We're in the middle of that heat wave now too.

Here's why it makes MG worse. We have fewer muscle receptors for the acetylcholine to go through to make our muscles strong. So many of us use Mestinon to keep what acetylcholine (ACh) we have in the neuromuscular junction longer. Mestinon is a "cholinesterase inhibitor." It inhibits an enzyme called "Acetylcholinesterase" or AChE. Normally, it's a perfect checks and balances system in the body. ACh goes in and makes muscles strong and then AChE goes in and "mops up" afterwards so we don't get too much of a good thing.

What heat does (cold too to some degree) is to increase that enzyme, therefore mopping up too much acetylcholine before we have a chance to use it.

What humidity does is not allow our bodies to sweat. If we can sweat, we can't cool down. If we can't cool down, more of that enzyme gets produced.

I hope that doesn't confuse the issue. Just stay out of the heat! And that includes heat from exercise, activity, infection or whatever.

Annie