Heat Exhaustion and Heatstroke

With the weather warming, it’s time to start thinking about heat exhaustion and heatstroke. Heatstroke is the more severe condition. Heat exhaustion usually comes before the heatstroke.

Why avoid heatstroke? The short answer is that it can be fatal.

Heatstroke, also called sunstroke, is the condition of having a core body temperature greater than 104 degrees Fahrenheit. This is dangerous for much the same reason that fevers are dangerous.

The proteins that make us up are folded into very specific shapes- and need to be in order to function. When heated, proteins unfold or denature. When cooled, they don’t always go back to their previous shape (in the same way that cooling an egg does not uncook it). This is why rapid treatment is important with heat stroke- long term organ damage and death are possibilities.

Symptoms of that very high body temperature? Nausea, seizures, confusion, heavy sweating (or sweating that has stopped), loss of consciousness, fast heart rate.

Heatstroke doesn’t typically happen out of the blue. It’s preceded by other heat related illnesses. Fainting due to heat, heat cramps, and heat exhaustion can all come before heatstroke. While the lesser heat induced illnesses are all treated by moving somewhere cooler, drinking fluids, and perhaps a cold bath… drinking water isn’t suggested for heatstroke. The reason for this seems to be that people suffering heatstroke may not be able to swallow safely. It isn’t that someone with heatstroke shouldn’t be given water -but keeping them from choking should be a consideration.

Heat exhaustion shares some symptoms with heatstroke. The difference matters, since heatstroke means medical attention is a necessity. Heat exhaustion can include a weak and rapid pulse, profuse sweating, headache, muscle cramping, and skin that is cool and clammy (potentially even with goosebumps) regardless of extreme heat.

While fainting can be a symptom of head exhaustion, first symptom of heatstroke is often fainting. Unconsciousness that lasts for more than a few seconds is cause for concern. At the transition from heat exhaustion to heatstroke, sweating decreases and skin changes from cool, pale and clammy to warm and red. As sweat evaporates and is not replaced, the skin becomes dry.

Who’s vulnerable? The young and the elderly, but also anyone outside exerting themselves when it is hot. Additionally, anyone not accustomed to hot weather- which, since acclimatizing typically takes several weeks, probably describes many of us right now.

So, take it easy. Stay inside during the warmest parts of the day. Drink lots of water to avoid dehydration (not the same as heatstroke, but a contributing factor and dangerous in its own right). Keep an eye on your friends and neighbors, and if they’re starting to look like they aren’t feeling so well, get them some rest somewhere cool and keep them company. If someone suffering heat exhaustion isn’t improving once they’ve had a chance to cool down, hydrate, and rest, it’s time to consider medical attention. Heat induced illness isn’t something to take lightly.

Ask The Entomologist

Cicadas – not just Brood X!

Chances are you’ve seen internet articles about the mass cicada emergences that’ll be happening across the eastern United States this year. Here’s a decent writeup from the National Park Service.

Periodical cicadas are named for the long stretches of time between their emergences (13 or 17 years, depending on the lineage). The thought is that this makes them an unreliable source of food for predators – it’s hard to be a specialist wasp if your food species vanishes and is unaccessible below ground for over a decade at a time.

And, when you emerge, surrounded by thousands of others like you, it’s statistically unlikely that you’ll be the one who gets eaten – be it by bird, dog, or unattended small child. Though many of your kin will be devoured, you’ll probably be safe. It’s the same tactic the now-extinct Passenger Pigeon used. Passenger Pigeons built undefended nests on the ground, and relied on numbers to make any individuals odds of survival better. A tactic that worked excellently until it didn’t.

Here we have a little member of genus Okanagana, the whip cicadas.
Fittingly for this area, they’re named after one of Canada’s First Nations which spoke a Salish tongue.

While we don’t have periodical cicadas (genus Magicicada) this far west, we do have other types of cicadas, especially genus Okanagana. I’ve been hearing their males sing in the trees on my drive back from work over the past couple of weeks. One way cicadas avoid predators is by being active in the sweltering heat when nothing wants to hunt. Cicadas cope with the heat by drinking tree sap nearly constantly, and releasing excess moisture through pores in their thoraxes, much like how we humans sweat to cool down.

Our cicadas here have life cycles maxing out in the 3-year range. As such, these species can be pretty reliable hosts for certain predators, like the cicada killer wasp… but our cicadas lead a charmed life. The Western Cicada Killer Wasp only goes as far east as Idaho, and the Eastern Cicada Killer Wasp only really goes as far west as the Dakotas.

Our local cicadas are convinced that this truly is God’s country.

An Okanagana cicada I met last fall – note that this one has brighter orange markings.