Know your limits when exercising

[00:00:00] Host Amber Smith: Here's some expert advice from Dr. Carol Sames from Upstate Medical University. What's important to know about heat illnesses?

[00:00:10] Carol Sames, PhD: Heat cramps are probably, if you've been out and you've done something that's fairly strenuous, you're used to heat cramps. It's almost like night cramps, where you have a muscle group, sometimes the calf muscle or the upper leg muscles, they just start to cramp. And it is very uncomfortable. Sometimes they'll continue to cramp. They won't relax. And that's a heat cramp. And really, it occurs because there's an imbalance between body fluid and electrolytes. What you need to do is stop, and you need to drink water or sports drink.

That should resolve. It's not going to resolve immediately, though. You're not going to just drink and be like, "Heat cramps are gone!" Most likely, what you're going to have to do is, if you were running, you're going to need to walk. If you were cycling, and it's bad enough, you're going to have to get off that bike. But that's what you need to do to resolve that situation.

The next two are what we consider more extreme heat illnesses. So, heat exhaustion, and that's when we don't have enough circulation to evaporate that heat that we're building up, and so, we start to lose blood volume, and we start to lose body volume.

In terms of "How do I know I'm kind of moving from heat cramps to heat exhaustion?" -- if I would take my pulse, it would be weak and very rapid. Usually when we're exercising, you can feel your pulse. It's nice and hard and steady. But with heat exhaustion, it's weak. You also might start to experience a headache because you're not getting enough blood flow to your brain, dizziness, and you just generally don't feel well.

You need to stop exercising. You need to move to a cooler location, under a tree, somewhere where there's shade. If you can get indoors where there's some type of air conditioning, that's even better, and you need to replace fluids. You might even need to go to the hospital and get an IV (intravenous fluids) -- kind of depends on how depleted you are.

The worst heat illness is heatstroke, and it is an immediate medical emergency. This is not something where people are like, "Should I go to the hospital or not?" because it's a cascade of events. Basically we have no more heat regulation going on, so we're no longer sweating. Our skin is hot to the touch. It is not moist anymore. Core temperature is at about 104 degrees or higher, and the body does not tolerate that type of extreme temperature. You end up with central nervous system failure, so a person might start to look very uncoordinated. All of a sudden, they can't stand. They may stumble and fall. You're starting to get organ failure, kidney failure, and people can progress really quickly from delirium to convulsions to coma. That's why this is a medical emergency. They need to get immediately to the hospital. They need to be immersed in cold water, ice, they need immediate fluid, IV immediately.

And you'd be surprised; even highly trained athletes have died from heatstroke. It is really problematic because when it starts, it's like a downhill car. It moves quickly.

Know what your limits are, right? So, like, you can't go from zero to hero. If I've not been active, I need to know that it's going to be a slow and steady progress. I need to make sure that I'm not dehydrated, and that I'm taking in enough fluid.

So that might mean if I'm out doing an activity, that I bring water, sports drink, with me, or that I have stops along the way where I can drink. In terms of older adults, it's very important to understand that we lose a thirst drive as we get older. Essentially, what we say is that after the age of 65, almost every adult is dehydrated, to start. So, if you're dehydrated to start, and then you go out, and it's warm, and you're exercising, you're becoming even more at risk of dehydration, and then, kind of that cascade of heat illness. So, that's really important.

I just really think it's always good to carry something with you, some kind of fluid. You never know. Especially if you're going to go out, you don't really know how hot it's going to get. The way we protect ourselves and keep our body temperature low, the primary mechanism, is evaporation of sweat. So when sweat is rolling off of us, we are not evaporating. And if we're not evaporating, we're not cooling, because that evaporation is going to cool the blood that is at the surface.

And so in the morning, usually the sun is lower, so you don't have that direct thermal heat on you, and it's usually cooler out. It could still be high humidity, but it's cooler, and so, we are able to evaporate. If it's a hot day, and there's no wind at all, and it's humid, you need to be smart. You want to make sure you have proper clothing. I might want to have a hat on. I have fluids with me. I might want to be with somebody, or I might want to go to an area where there are other people, that I'm not completely isolated.

Generally speaking, unless you acclimatize to running at noontime in the summer, you're going to run into trouble. Yes, you can see people outside; I see noon runners all the time, but they have been doing that consistently. And so they have acclimatized to training, and there's actual changes that occur in the body that your body gets used to not producing as much salt-laden sweat. You tend to conserve. And we're also assuming these individuals are hydrating themselves properly before they go run at noon.

There's a reason why I, personally, run in the morning. I don't heat-acclimatize well. I don't feel good in the heat, and so I would much rather get up in the morning before it gets really hot and just get something done. I'm impressed by those noon runners, but it could never be me.

We all have to listen to our body, right? So if it's really hot, and I'm out there, and maybe I didn't really hydrate well, I'm out in the sun, I'm maybe running on some type of asphalt, and I start to feel, like, hot, and I start to feel maybe a little dizzy, and I'm just not feeling well. That's your body saying, "This is not the right situation for you."

You have to listen to your body. The body usually tells us, and it's just when we try to ignore our body that we generally run into issues.

[00:06:14] Host Amber Smith: You've been listening to exercise physiologist Carol Sames from Upstate Medical University.