Calories burned vs. calories consumed

Calories burned vs. calories consumed

How many calories should you consume in a marathon swim?

According to an article on the “Nutrition Demands of Open Water Endurance Swimming,” swimming burns 2.93 calories per mile, per pound. The author, Don Macdonald, did the math and figured that he burns approximately 15,000 calories during a 24-mile swim. Later in the article, Macdonald goes on to say:

As you can imagine, it is difficult to eat 15,000 calories over a 13-hour period without training the stomach to handle this input.

Leaving aside the reasons (discussed previously) that the above formula is probably bogus, let’s think about this: eating 15,000 calories in 13 hours. That’s 1,154 calories per hour. Burning this many calories is one thing. You might be able to do it for an hour; probably not for 13 hours straight. But consuming that many calories is something else entirely.

Can you guess what would happen if you tried to consume 15,000 calories during a 24-mile swim? That’s right – you’d get sick and would not finish the swim. It’s not a matter of – as Don Macdonald says – “training the stomach to handle this input.” Nobody can train their stomach to process 1,150 calories/hour for 13 hours, while simultaneously swimming 24 miles.…

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Swim efficiency and energy consumption

Swim efficiency and energy consumption

In the last post I bemoaned the lack of credible science about marathon swimming. One is reminded of the William Goldman quote about the movie industry: Nobody knows anything.

Here’s a good example. A few days ago a Facebook friend linked to an intriguing-looking article. Published on a science-y looking website (“Your one-stop resource for longevity, health, exercise, nutrition, and scientific articles all to help you live a longer, fuller life”), the article is authored by marathon swimmer Don Macdonald.

One section seemed of particular interest: “Nutritional Demands of Open Water Endurance Swimming.” An excerpt:

Nutritional endurance demands biochemical changes of your body. The basic calculation for the amount of calories burned while swimming is 2.93 calories per mile, per pound. I weigh 207 pounds, and therefore burn 14,556 calories in a 24-mile swim, (2.93 calories x 24 miles x 207 pounds = 14,556 calories). You must also add 10-15 percent of your burnt calorie total for the energy it takes your body to keep itself warm. In this case, adding another 1,500 calories.



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On science in marathon swimming

On science in marathon swimming

In marathon swimming, there’s very little in the way of credible science – that is, methodologically rigorous, experimentally controlled, peer-reviewed science. It’s not hard to understand why: Open-water swimming, especially the marathon variety, is a tiny market compared to land-based endurance sports. Market size is related to the potential for making money, and the potential for making money is, in turn, related to funding and motivation for scientific research. Even in triathlon (an enormous, lucrative market), swimming is often seen merely as a warm-up to the bike and run, so there’s little effort to understand it.

As a result, marathon swimmers are left with approximately four strategies for acquiring knowledge about their sport – specifically, the physiological demands of long-distance swimming, and the nutrition required to fulfill those demands:

  1. Figuring out what is known, scientifically, about land-based endurance activities, and applying it to swimming.
  2. Figuring out what is known, scientifically, about pool swimming (in which races last anywhere between 20 seconds and 15 minutes), and applying it to marathon swimming (in which a race or solo event may last 10 or 15 hours).


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On Maltodextrin: Maxim vs. Carbo Pro

On Maltodextrin: Maxim vs. Carbo Pro

Among channel swimmers, the Danish sports drink Maxim is something of a magical elixir. The reasons for this are beyond the scope of this post, but for additional details I recommend a search of the Channel Swimmers chat archives – especially posts by CS&PF pilot Michael Oram.

Maxim is an excellent product. Indeed, it fueled three of my four ultra-marathon events this year (Tampa, MIMS, and Catalina). What’s interesting about Maxim is how simple it is. The ingredients: 97% maltodextrin, with a smattering of Vitamins C and B1. Maltodextrin is a complex carbohydrate of chained glucose polymers, and is the basis for other popular endurance fuels including Perpetuem, HEED, and EFS. Maxim, however, has no added protein (Perpetuem), no added amino acids (EFS), and no added electrolytes (all three).

As you know if you read my DIY recovery drink post, bulk maltodextrin is available very cheaply – much cheaper than Maxim. So why pay $28 + $8 S/H to ship Maxim from the UK? (There is no currently no American importer of Maxim products.) Is Maxim maltodextrin superior to bulk maltodextrin?…

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Sharing the water with giants

Sharing the water with giants

The blue whale is the largest known animal to have ever existed – up to 110 feet long and weighing nearly 200 metric tons. The whales are drawn to the deep waters off the coast of Southern California in late summer and fall to feed on krill (up to 40 million a day for an adult).

These magnificent, peaceful creatures were hunted nearly to extinction in the 20th century. Though still endangered, their West Coast population (estimated at 2,500) has been gradually recovering – to the delight of whale watchers… and swimmers of the Catalina and Santa Barbara Channels!

Check out this guy kayaking with them off Redondo Beach a few days ago. See, especially, the underwater shots at 1:12 and 2:15.

I’ve never been much of a museum guy – even less so when I was kid. But I fondly remember one particular exhibit at the Santa Barbara Museum of Natural History (a popular field trip destination at my elementary school): the blue whale skeleton! Turns out it’s still there.

For an interesting description of how blue whales fit into the incredibly diverse ecology of the Santa Barbara Channel Islands, see this article.…

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Hidden gems of YouTube: “The Crossing”

Hidden gems of YouTube: “The Crossing”

I’ll go out on a limb and say: This may be the best video ever made about a marathon swim. At least, it’s the best one I’ve seen (and I’ve seen a few). Perhaps it’s more appropriate to call it a “short film.” The production values are that high.

The film, by Stephen Lewis, tells the story of Marc Lewis’ unprecedented 27.5-mile swim between Santa Rosa Island and the California mainland in 2008. It features 720p video quality, an imaginative soundtrack of Sigur Ros, The Ventures, Radiohead and Beethoven, stunning photography of the Santa Barbara Channel, and thoughtful interviews with Marc’s family, coaches, observers, and crew.

The cast reads like a “who’s who” of So-Cal marathon swimming. Carol Sing and Forrest Nelson as observers; David Clark as swim coordinator; Bob West, godfather of the La Jolla Cove Swim Club; Sickie Marcikic, head coach of UCSD Masters. Marc had some incredible folks supporting his swim; listen closely to what they have to say.

“The Crossing” captures the beauty of an open-ocean channel swim, but also accurately reflects the monotonous reality of swimming and crewing such a swim.…

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Rules on Catalina tandem swimming

Rules on Catalina tandem swimming

Correcting a bit of misinformation from the comments section of a recent post…

Tandem swimming is allowed on Catalina swims, so long as each member of the tandem is sanctioned by CCSF. This is from a CCSF official:

The CCSF recognizes a difference between a SANCTIONED swimmer and a COMPANION swimmer. Sanctioned tandem swims are allowed.

What’s at issue is the COMPANION swimmer, who typically knows the swimmer but has no relationship with the CCSF (eg application, swim history, insurance). For safety purposes, the CCSF wishes to limit that swimmer’s time in the water to a maximum of 3 hours in shifts no longer than 60-minutes. That’s more in accordance with English Channel standards. Different than Dover, a CCSF swimmer could– if they so desired– recruit 5 companion swimmers. Technically, they could rotate 1-hour legs for a 15-hour crossing (5x 3-hours). I have also pondered having a tandem event from the same boat: One solo swimmer going side-by-side with a 6-person relay. Though, it would take some serious synchronized swimming to make that feasible….

The SBCSA also allows for tandem swimming (with each swimmer being sanctioned), but has not yet followed CCSF in adopting a 3-hour limit on pace swimmers.…

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