Heat wave lesson: Hydration is key, especially for older people

We may not know for a while just how many people died as a result of the unprecedented three-day Northwest heatwave that prompted more than 460 heat-related emergency room visits in King County; at least 13 people died. Many were older adults.

With the human-driven changes in our climate, this may not be the last heat event that could cause such casualties.

Dr. Wayne McCormick is the head of Gerontology and Geriatric Medicine at the University of Washington Medicine. He told KUOW’s Kim Malcolm about how extreme heat affects older people, and how to prepare for the next wave.

This interview has been edited for clarity.

Kim Malcolm: You were in the thick of this. What did you see in your patients as they were coming in the early part of this week?

Dr. McCormick: Some of my interactions were here at Harborview Medical Center, some were over the phone or Zoom meetings with patients, and then I'm responsible for the care of some patients in nursing homes. Certainly, there was great suffering from the heat wave, particularly among older individuals, but really anyone with significant debility needed extra help during these past few days.

Fortunately, it seems to be tapering off now at the Medical Center. I'm in clinic today and have taken care of a couple of people with heat-related symptoms. Again, I'm glad that it seems to be abating.

The heat has been off for a couple of days, but you're still seeing the impact in your clinic.

Dr. McCormick: Yes. A couple of people came in and said they hadn't slept for days, and were having trouble keeping anything down, and were having trouble cooling off even today, which seems like a pretty typical Seattle day. Then, we've had to give them IV fluids in clinic to get them feeling better, which is the hallmark of heat-related problems. It's mostly about hydration.

Older people often need quite a bit of extra hydration during heat-related times. That's the advice that we give people over the phone and directly, to drink far more fluids than they think they need.

We know that many of the folks who were impacted by the heat are older, or have underlying conditions. Why are they more vulnerable? What happens to your body when you get overheated?

Dr. McCormick: A few things. As we achieve older age — the average age in our clinic is in the late 80s — people in their 80s and 90s have more difficulty auto-regulating their heat. It's remarkable that we as organisms and all mammals, being warm-blooded, regulate our body temperature within a pretty tight margin around 98.6. But we lose the ability to do that as well as we age.

The other thing that happens to older people is the skin, which is an enormously important organ in our body, has less insulation and is less able to moderate fluids and heat than when we're younger. So you lose more fluid through your skin, you're not as well insulated, and therefore your body temperature fluctuates much more and is less controllable by your nervous system than when you're younger.

And why is it more dangerous when your body starts to warm up like that?

Dr. McCormick: Well, we're not used to sensing that. I mean, when we feel dizzy, we sit down, but it's hard to pay attention to the symptoms of heat-related injury. It's a gradual, insidious kind of clouding and wooziness that kind of sneaks up on us. We're not evolutionarily very well built for it. It's really a phenomenon of last century that people have lived in large numbers to their 80s and 90s.

In our several 100,000 year history as a species, this is pretty new, that there are so many older people around, and we haven't evolved to be able to manage that.

The extreme heat earlier this week made many people quite sick. Why did so many people end up in the emergency room?

Dr. McCormick: My patients in clinic today are great examples. They get gradually sicker and sicker and then get into a spiral where they're unable to take in more fluids, for one reason or another. They can't think straight, don't have access, or develop gastrointestinal symptoms where they get nauseated or vomiting. Then it turns into a vicious cycle where they just simply cannot keep up and need enormous amounts of fluids.

Both of my patients here today are kind of frail older individuals in their 80s. Both got two liters of fluid, that's half a gallon. And I'm sure our listeners can imagine what it's like to drink half a gallon over a period of about an hour and a half. That's quite a bit of fluid. But these two got it intravenously because they were nauseated, and we're able to reach equilibrium again, but that's what it takes.

Last week, the forecasters were telling us, we're going to be hitting 100 and more, 105, 108. It seemed kind of unreal at the time, but we knew it was coming, and still, people died. Is that because people just didn't realize how damaging this heat could be? What else do you attribute it to?

Dr. McCormick: You know, I think people take it in. It's just hard. We're not practiced at it, first of all. We're out of practice dealing with that high level of heat. And it's hard to be preventive in the way that we tell people. It's one thing to tell people to be careful.

It's not very helpful advice to a debilitated older individual, to tell them to go to a cooling center, if over the past couple of years, they're very used to not leaving their home, because of Covid. That's not practical advice to some of our very old patients. Practical advice is to get to the coolest place you can, a basement, or if there's any air conditioning or place with a fan, that's great, but the main piece of advice is to drink enormous amounts of fluid.

We know that more than half of the households in the Seattle area do not have air conditioning. Could we have done more to protect people that we knew were vulnerable, like gathering up those folks without air conditioning who'd be particularly vulnerable to this heat and bringing them to cooling centers?

Dr. McCormick: If we see it coming again, that's probably a good idea, but there are very large numbers of old frail individuals in our metro area now. There are well over 500 people over 100 years old in King County. That's not even newsworthy anymore to be over 100 years old. They're just more susceptible than others. That many people over 100 — there's tens of thousands of people over age 90, in King County — I don't know that our cooling centers are that big, or that it's actually practical to get that number of people to cooling centers.

Nevertheless, that's good advice. To the extent we can accommodate that and be ready for next time, that's something we should try to do. That would be one tool in our toolbox to help with a heat event like this.

Listen to the interview by clicking the play button above.