Dinesh’s Mid-Summer Death Valley Walk (1998)(dineshdesai.info)
dineshdesai.info
Dinesh’s Mid-Summer Death Valley Walk (1998)
https://dineshdesai.info/dv/photos.html
41 comments
Your reaction to heat is highly dependent on acclimation. I live in Texas and have to re-acclimate every year. Exercising on the first 85º+ day of the year is miserable, but a month later 85º feels quite tolerable, and 95º is doable, though performance suffers.
I grew up playing baseball and tennis in 95-100º weather with high humidity routinely. It wasn't pleasant, but nobody was getting heatstroke, nobody was cancelling games or practices. But on a visit to Montana a few summers ago, I saw that kids' baseball games had been cancelled because the temperatures had reach a dangerous level: 90º (in dry mountain air.) Same human beings, different levels of acclimation, very different safety thresholds.
I've never been in the temperatures described in this article, though, and I don't know what the physical limits of acclimation are.
I grew up playing baseball and tennis in 95-100º weather with high humidity routinely. It wasn't pleasant, but nobody was getting heatstroke, nobody was cancelling games or practices. But on a visit to Montana a few summers ago, I saw that kids' baseball games had been cancelled because the temperatures had reach a dangerous level: 90º (in dry mountain air.) Same human beings, different levels of acclimation, very different safety thresholds.
I've never been in the temperatures described in this article, though, and I don't know what the physical limits of acclimation are.
> Your reaction to heat is highly dependent on acclimation.
And the other way around.
I once went to a conference, held in early spring, at a Greek hotel. It was 15 C and the hotel staff had closed the pool as it was "too cold" to swim.
Us Brits were puzzled. The Finns were utterly baffled.
And the other way around.
I once went to a conference, held in early spring, at a Greek hotel. It was 15 C and the hotel staff had closed the pool as it was "too cold" to swim.
Us Brits were puzzled. The Finns were utterly baffled.
If the pool is heated, swimming in 15C weather would be fine. If not, I wouldn’t swim in 15C water without spending time in a sauna or hot tub before jumping in; surfers wear wetsuits when the water is that temperature.
The "trick" I used in GA (not quite as hot as TX, but as humid in that part of GA) was to exercise outside year round. It was rarely so cold that winter running was a problem, and as the temperatures warm up or cool down you naturally get acclimated to the new season. It's worked here in CO as well (though due to an injury I didn't this past winter) with getting used to very cold temperatures (I wouldn't exercise outdoors on our very coldest days, but that's about 1-2 weeks out of the entire winter that I'd stick to indoor only training).
I occasionally ride my bicycle to work in Austin and some days when I get home I have a hard time cooling down even after a long cold shower. I've since set a rule for myself that I won't ride on days where the temperature is 98 or higher.
I just turned 55 and have been thinking about this a little, wondering if maybe I should back off on the biking?
I just turned 55 and have been thinking about this a little, wondering if maybe I should back off on the biking?
Maybe do it more consistently! Heat acclimation takes a week with daily exposure or 2-3 weeks if you get exposure every other day[0]. If you work out in the heat once a week, you might be living that miserable first hot day of the year over and over again all summer.
[0] I don't know how well nailed down this is, but I didn't find any wildly differing opinions in my internet research: you achieve roughly 80+% of the heat adaptation you're capable of in this time period, assuming 90 minute sessions with physical activity.
[0] I don't know how well nailed down this is, but I didn't find any wildly differing opinions in my internet research: you achieve roughly 80+% of the heat adaptation you're capable of in this time period, assuming 90 minute sessions with physical activity.
Not a medical expert by any means, but 98 degree Fahrenheit sounds like a dangerous high temperature for exercise (at high humidity, I'm sure it is). I'd go earlier / later in the day, when temperatures are more reasonable. There is a reason for Siesta.
The first exercise at 105⁰ seems insane. A week later bearable.
I recall with some amusement thinking I was coming down with heat stroke one summerbecause the light wind felt chilly on my skin. But then I realized it was only 95 degrees
I recall with some amusement thinking I was coming down with heat stroke one summerbecause the light wind felt chilly on my skin. But then I realized it was only 95 degrees
I live in Midwestern US and the early spring has 50 degree mood swings. A few days of highs pushing 90F and then morning lows in the 30's.
Go to work freezing, spend all day in a dry 70F office and then come out into an afternoon sauna.
Go to work freezing, spend all day in a dry 70F office and then come out into an afternoon sauna.
What really matters is the wet bulb temp. For example, the Death Valley high today was 114°F (45°C) but at an RH of only 3%. That gives a wet bulb temp of ~ 65°F which isn't a problem with acclimation and adequate hydration.
Now if it had been 50% RH, the web bulb temp would be > 96°F which is not survivable by humans for very long because no amount of sweating in that humidity will cool you down.
Now if it had been 50% RH, the web bulb temp would be > 96°F which is not survivable by humans for very long because no amount of sweating in that humidity will cool you down.
That's 114°F in the shade. There is no shade in the desert though ...
Don't want to be projecting, but first time I went to Death Valley happened to be in August. I saw dunes from the car and thought I had to walk up there. Fifteen minutes later I had an unbearable headache and quickly headed back. Sombreros don't look all that ridiculous to me anymore.
Don't want to be projecting, but first time I went to Death Valley happened to be in August. I saw dunes from the car and thought I had to walk up there. Fifteen minutes later I had an unbearable headache and quickly headed back. Sombreros don't look all that ridiculous to me anymore.
A young couple and their baby and dog died of overheating on a day hike in California a few years ago.
https://www.theguardian.com/us-news/2021/dec/12/tragic-death...
https://www.theguardian.com/us-news/2021/dec/12/tragic-death...
Taking a 1 year old on an 8mi/13km hike in an area where temps go to 109F/43C, with inadequate clothing and only 2.5l of water for 2 adults, the child, and the dog is insane.
Bike riding in the heat once caused me to come close to overheating. Stopping, finding shade, pouring water over my head and laying down finally brought my core temperature down in time.
I saw the same things begin to happen to my wife some years later when bike riding in the heat. I did the same for her and all was well.
I saw the same things begin to happen to my wife some years later when bike riding in the heat. I did the same for her and all was well.
The real problem is HVAC. You are acclimated, but you acclimated to the thing you spend the most time time. If you want to get used to higher temperatures, spend about 2 weeks without AC, or with the AC only kicking on at a high temperature.
> Now, I actively avoid anywhere much hotter than about 80F.
It is currently - well after sunset - 82°F outside. A couple days ago it was mid-90s in the afternoon, and it should get back to that after the current weather passes in another few days.
Mowing the yard when it's high 90s and muggy and sunny is not as rare an occurrence as I might like.
It is currently - well after sunset - 82°F outside. A couple days ago it was mid-90s in the afternoon, and it should get back to that after the current weather passes in another few days.
Mowing the yard when it's high 90s and muggy and sunny is not as rare an occurrence as I might like.
Pairs great with the tale of the Death Valley Germans: https://www.otherhand.org/home-page/search-and-rescue/the-hu....
I get a 401 error with that link, but when I visit it from a search engine it's fine. I think they may have blocked referrals from HN, so if you see that message, try copying-and-pasting the URL into a new tab / window / incognito window. I read this a while ago, and as other say, it's worth it.
bizzarely the owner has put it behind a password login in the past few minutes. Still on the archive tho:
https://archive.is/Zuz68
https://archive.is/Zuz68
I use Smart Referer to disable this, but the extension appears to be unmaintained:
https://gitlab.com/smart-referrer/smart-referer
https://addons.mozilla.org/en-US/firefox/addon/smart-referer...
Anyone know of a reputable replacement?
https://gitlab.com/smart-referrer/smart-referer
https://addons.mozilla.org/en-US/firefox/addon/smart-referer...
Anyone know of a reputable replacement?
This was a great read, thank you for sharing it!
I love it! This was what the ultra marathon community used to be like before it became commercialized and professionalized (https://mattmahoney.net/ultra/, especially the story of Gravel Man https://mattmahoney.net/ultra/death600.txt). Now you can't run 50k without a crew.
EDIT: And this is what a serious amateur can do on that route: https://www.latimes.com/california/story/2022-03-10/astrophy...
EDIT: And this is what a serious amateur can do on that route: https://www.latimes.com/california/story/2022-03-10/astrophy...
> Now you can't run 50k without a crew.
Thousands of people run 50k's without a crew every year, worldwide. Maybe even just within the US, even.
Also, Hummels did his traverse in February; TFA is about doing something in July. In Death Valley, that's a world of difference.
Thousands of people run 50k's without a crew every year, worldwide. Maybe even just within the US, even.
Also, Hummels did his traverse in February; TFA is about doing something in July. In Death Valley, that's a world of difference.
Yes, Hummels was going for speed. See the Mahoney link for people doing various DV crossings in peak heat.
Matt is such an interesting character; he once had a foot issue that he fixed with a wooden insole.
Fun fact about Matt, he built a great compression algo as well.
Fun fact about Matt, he built a great compression algo as well.
Maybe that's what I enjoyed about the old-school ultra crowd -- they were a bunch of unpretentious geeks with day jobs, doing outdoor stuff as a serious hobby rather than a calculated bid for attention and sponsorship. You can still find them, but you have to look harder.
Nicely written. I liked the Car Talk captions. Would have loved to see larger images though. But I understand this is from 1998.
Looks like the same guy : https://www.turtletrader.com/dinesh-desai/
Interesting that they didn't find the nights too cold for sleeping out. We camped in Racetrack Playa one spring some years back and the nights were bitterly cold with extreme wind.
That's Death Valley Dinesh!! I just re-heard that episode on "Best of Car Talk"
Yes, me too! Long live Car Talk!
https://www.npr.org/2025/06/10/1253920678/-2546-death-valley...
https://www.npr.org/2025/06/10/1253920678/-2546-death-valley...
I wish it was still easy to obtain the episodes of car talk that aren't on any of the collection CDs.
Then, without trying, I overheated simply by exercising in a room that I didn't know was 95F.
(Since I've mostly only lived in cold/moderate climates, and had never learned how risky 95F is.)
It was highly unpleasant, in an uh-oh, I can see how people die this way, kind of way.
Now, I actively avoid anywhere much hotter than about 80F.
Just last week, I declined a very interesting recruiting outreach from a CEO in Austin, telling him, sorry, but the weather in Texas is just too hot for me.
I'm ready to repurpose the term "special snowflake".
> A young woman seems to be walking around in a daze. [...] I don't think they believed their guidebooks about how uncomfortably hot it can get in Death Valley.
I hope someone helped the dazed person with first aid. And that other people take the heat seriously. It's right there in the name: Death Valley.