Tag: hydration

Posted on

NYT: hiking the Larapinta Trail in the Australian outback

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

Another slightly off-topic post… An article describing my recent hike along the Larapinta Trail, a fantastic route through the empty desert west of Alice Springs in Australia’s “Red Centre,” will run in this Sunday’s New York Times travel section. Actually, it’s not that off-topic — for this hike, we had to pay very close attention to factors like hydration (a frequent Sweat Science topic), since there was literally not a drop of water available other than occasional rainwater tanks. Along some sections of the trail, the distance between tanks was a nine- or ten-hour hike at a pretty fast clip. We met some hikers who couldn’t make it that far in a single day, and were thus forced to carry enough water for two full days with them (and that includes cooking water).

Anyway, it was a great hike — a chance to see some unique and inaccessible landscape, and a real test of endurance. The story is online here.

Posted on

Slushies: the new weapon for exercising in heat

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

Reading up on Australian sports research for an upcoming magazine story, I came across this little nugget about dealing with competition in hot conditions. The Aussies have been leaders in research on “pre-cooling” to lower body temperature before starting extended exercise in the heat. They introduced ice vests at the 1996 Olympics (which have since become widely used commercial products), and in 2004 brought big bathtubs full of ice-water to the Athens Olympic venues, actually immersing their endurance athletes shortly before their competitions.

I can’t imagine the pre-race ice bath becoming a really widespread phenomenon, for many reasons including logistical ones. But for the Beijing Olympics in 2008, the Aussies unveiled a new idea: slushies! As Louise Burke, head of sports nutrition at the Australian Institute of Sport, explained at a conference in Switzerland last fall, ingesting crushed-ice drinks cools the athletes internally — not just with the coolness of the ice, but with the energy of the phase transition as it melts. In tests, the Aussies found their athletes lowered their body temperature by about one degree Celsius by drinking the slushies (which were filled with “a mix of carbohydrates, electrolytes, and ice with other secret ingredients“). So the Australian Olympic team brought seven slushie machines to Beijing.

Other interesting points from Burke’s talk in Switzerland: The ice baths actually lowered body temperature more than the slushies, but this turned out to be a negative. In cycling time-trial tests, the athletes felt so good after the ice baths that their internal pace regulation was messed up, so they started too fast and paid for it late in the race. The slushie-fed athletes, on the other hand, started a little slower but ultimately performed better.

And the other reason the Aussies introduced slushies in 2008? They wanted to have something new, Burke says, to elicit a placebo response in their athletes.

Posted on

Homemade sports drinks

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

A few months ago, I promised to look into how to make your own sports drink at home. It has taken me a while to follow up, but I thought I’d pass the following along. From the book “Nancy Clark’s Sports Nutrition Guidebook,” as cited in a New York Times blog entry:

1/4 cup sugar
1/4 teaspoon salt
1/4 cup orange juice
1/4 cup hot water
2 tablespoons lemon juice
3 1/2 cups cold water

In a quart pitcher, dissolve the sugar and salt in the hot water. Add the remaining ingredients and the cold water. The drink contains about 50 calories and 110 mg of sodium per 8 ounces, approximately the same as for most sports drinks.

Posted on

Drinking too much during marathons (hyponatraemia): an update

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

Just noticed a University of London preprint that has been accepted for future publication in the British Journal of Sports Medicine that looks at incidence of hyponatraemia in the 2006 London marathon. This topic has received a fair amount of attention in the past few years (justifiably, since at least five people have died recently in the U.S. and Britain, according to the paper), but there are a couple of new wrinkles in this paper.

First of all, this wasn’t your typical hot marathon where people are pouring fluids down their throat with abandon — the 2006 London race was held in “wet, rainy conditions with air temperature 9-12 [degrees] C.” Still, 11 of the 88 runners studied developed “asymptomatic hyponatraemia,” as diagnosed by low sodium levels. They didn’t have any negative effects — or any symptoms at all, actually — but they were on the border, supporting the contention (the authors claim) that hyponatraemia is underdiagnosed.

As expected, the hyponatraemia sufferers drank more (every mile, most commonly, compared to every second mile for the non-sufferers), and they put on weight during the marathon on average, while everyone else lost weight. But there were some anomalies: four of the hyponatraemics actually lost weight, but still somehow ended up overhydrated. It’s not clear how this happened, though the researchers speculate about “inappropriate antidiuretic hormone (ADH) release during exercise causing altered renal function and secondary fluid retention.”

So what do we take from this? Well, it’s hard to get too worried about an asymptomatic condition that doesn’t cause any problems (though of course if they persist into the symptomatic regime, they risk serious problems). On the other hand, these results tell us that quite a few people are still chugging water well beyond their needs. So maybe it’s worth bearing in mind the words of Tim Noakes, the respected South African sports scientist who has been stirring up dissent about our current obsession with proper hydration: “If you are thirsty, drink; if not, do not,” he wrote in 2007. “All the rest is detail.”

Posted on

The bare facts about heat stroke

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

In case summer ever decides to start, here’s an article on heat stroke from Gretchen Reynolds of the New York Times. The best line, relating to how heavy clothing can increase risk:

“I’m all in favor of naked practice sessions,” [University of Connecticut researcher Douglas] Casa says. Unfortunately, sunburn also is thought to have an impact on your abilitity to dissipate heat.

Other than that, nothing particularly surprising in the article — unfortunately, there’s no quick fix or miracle cure for heat stroke. It’s a matter of caution, acclimating to hot weather (especially if, say, an unusually cold and wet summer has limited your exposure to hot days), and looking out for warning signs like dizziness and confusion. Another interesting point: while hydration is important, it’s perfectly possible to get heat stroke even if you’re fully hydrated.