Posts from Oct 2011

Race Report: Ederle Swim

Oct 05 2011

Janet Harris

I met Janet Harris at a CIBBOWS gathering after the Great Hudson River Swim in May. A few weeks later, we swam side-by-side for a few minutes during the Manhattan Island Marathon Swim. Janet is known in the NYC-area swimming community for her infectious smile and tasty baked goods. Recently, she’s been making a name for herself as a marathon swimmer – as part of a 1st-place MIMS relay duo with John Humenik, and then completing two solo stages of the 8 Bridges Hudson River swim.

This past weekend, Janet placed a strong 5th overall in the Ederle Swim. Here is her race report.

I wanted to highlight Janet’s report because her experience, as she tells it, was everything mine was not (or everything I wish it had been). She writes of a tension between swimming “at sightseeing pace, taking my time and taking in all the beauty along the way and savoring the privilege of being able to swim under the Verrazano Narrows Bridge, by the Statue of Liberty,” on the one hand, and “giving it my very best effort, and pushing myself to see how I could stack up against a strong field of contenders,” on the other.

Somehow, she managed to strike a perfect balance between the two:

I felt like I was pushing myself beyond comfortable the entire time…. I was also constantly taking in and loving everything around me—the blue-and-puffy-clouded sky, the undulation of the waves, the feeling of being surrounded and supported by the water. I waved to the Romer Shoal Lighthouse and the Statue of Liberty as I passed by, blew a kiss to the VZ bridge as I backstroked under it, and was excited by the ever-nearing skyline of Manhattan. The whole swim was simply joyful, and was the kind of peak athletic experience where the more energy I expended, the more I felt like I had to give.

This is marathon swimming at its best, isn’t it? An epic physical challenge, and at the same time a joyful adventure. A chance to push one’s limits of endurance and pain, and also to experience geographical places in unique ways. Millions have driven over the Verrazano-Narrows Bridge, but how many people get to swim under it?

Under the VZ Bridge, on the way to Sandy Hook (photo by Vlad Brezina)

As I reflect on my season and look forward to the next one, one of my goals is to be more Janet-like. To experience my swimming more joyfully. There were many individual moments of joy this year, but they were always fleeting. As Janet showed, “joyful” doesn’t have to mean “slow” - and I can probably strike a better balance.

My typical experience during these swims has been as a struggle between body and mind. For how long can I maintain a certain pace? How much pain can I endure? A “masochistic death march,” is how I described it in a comment.

Not warm enough (photo by Kevin T.)

For me, the Ederle Swim was pretty much a death march from start to finish. Is it unsporting to suggest a swim that earned me a AP mention was actually my worst of the year? Probably. So I won’t dwell on it too much. My training since Catalina has been sporadic at best, so I shouldn’t have expected a peak performance. I didn’t bother to taper - there wasn’t anything to taper from.

But my big unforced error was dressing inadequately for the boat ride to Sandy Hook. Such a rookie mistake! After an hour speeding across the water at 20 knots in sub-50F air temps, by the time I arrived at the start I was chilled and tight. Though the water was warm enough (68F) that I was in no danger of hypothermia, I never really recovered. I just felt unbalanced and uncomfortable the entire swim.

These things happen… but I’m disappointed that I let it detract from my joy in experiencing this beautiful, historic swim. It’s a rare thing to backstroke under the looming Verrazano; to watch the lower Manhattan skyline grow on the horizon from water level; to share the water with impossibly large cruise ships and barges. That’s why people pay good money for this.

The blue Atlantic meets the muddy Hudson (photo by Rondi Davies)

We can’t always have good days out there. Some days, I’m sure even Janet would struggle to muster much joy - she’s human like the rest of us. The lesson, I think, is that on those occasional bad days, to the extent you can step back from the pain and appreciate the beauty and privilege of what you’re doing, your experience will be much the better. I’m ashamed to admit that I didn’t even see the Statue of Liberty as I passed it. I knew she was there, but I didn’t bother to look for her - I was too busy grinding. Three days later, I profoundly regret this.

A few words on my crew: I lucked out again. Manning the boat was my MIMS pilot Barry D.; paddling next to me was Kevin T. They steered me confidently through a multitude of odd currents and the confused chop of the final 2 miles. Pulling double-duty as official observer and crew was John Hughes - a warm and encouraging presence every 20 minutes when I stopped to feed. Thanks, guys.

So, that’s a wrap for my 2011 open water season! For now I’m taking a few days off to regroup and re-acquaint myself with the reality-based world. It’s tough to say what adventures 2012 will bring, but you’ll hear it here first. Thanks so much to my family and friends for their support and encouragement this year, and to my readers for their continued engagement.

May your off-season be joyful!

Approaching Manhattan from the south (photo by Vlad Brezina)

On Maltodextrin: Maxim vs. Carbo Pro

Oct 20 2011

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, 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? Do the added vitamins make a meaningful difference?

Maybe… maybe not. I’m no chemist. For what it’s worth, Maxim does seem to dissolve more readily in water than the bulk stuff. I don’t know why that is, or what it means. Possibly something to do with which grains were used to synthesize it.

In any case… getting to the point of this post. Remember the Ederle Swim earlier this month? Long story, but suffice to say: The night before the swim I discovered that I didn’t have enough Maxim to mix my feeds. Oh, f*ck. Where am I going to find Maxim at 7pm in New York City?

I didn’t find Maxim… but I did find a great little shop in midtown, Swim Bike Run. They carried a product, Carbo Pro, that appeared to be pretty similar to Maxim. Pure maltodextrin, and none of the other crap. To my delight, the Carbo Pro dissolved almost instantly into water - just like Maxim.

Even more to my delight, Carbo Pro worked great the next day, during my 17.5-mile swim - just like Maxim. As far as I’m concerned, the two products are interchangeable. The only difference being, Carbo Pro is easier to obtain in the US.

Price comparison (and this surprised me):

On science in marathon swimming

Oct 22 2011

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).
  3. Word of mouth - finding out what works for other marathon swimmers. This is how most people discover Maxim - because that’s what they use in the English Channel.
  4. Individual trial-and-error. Penny Palfrey likes watered-down porridge and chocolate ice cream. Who knew?

Most successful marathon swimmers use each of these strategies at some point. The problem with the hybrid approach, however, is that it neglects one very important thing: actual, science-based knowledge about marathon swimming. As science has continually shown since at least Galileo, there’s a lot we don’t know - and much of what we think we know might actually be totally false.

A few questions, off the top of my head:

The first in a three-part series. See Part 2 and Part 3.

Swim efficiency and energy consumption

Oct 29 2011

In the last post I bemoaned the lack of rigorous science about marathon swimming.

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.

2.93 calories per mile, per pound. Really? How do you figure?

Does it seem likely that calorie burn depends only on distance, and not the time taken to complete the distance? If I swim 10 miles in 4 hours, does a slower swimmer who takes 7 hours burn the same calories as me, despite spending 3 more hours in the water (assuming equal body weight)? Do I burn the same calories in a 1500m warm-up as during a 1500m race?

Actually, there is a school of thought (with some scientific basis) that calorie burn is independent of speed/time in “animal locomotion” generally. As Wikipedia (referencing a 1973 Science paper) explains:

The most common metric of energy use during locomotion is net cost of transport, defined as the calories needed above baseline metabolism to move a given distance, per unit body mass. For aerobic locomotion, most animals have a nearly constant cost of transport - moving a given distance requires the same caloric expenditure, regardless of speed. This constancy is usually accomplished by changes in gait.

The idea is, calories are a measure of work - the work required to move a given body mass a given distance. Hence the common rule-of-thumb in running: 1 calorie (technically, _kilo_calorie) per kilometer, per kilogram. Running at higher speeds burns more calories, but this is counterbalanced by the reduced time taken to complete the distance. More recent evidence has complicated this view – showing differences in calorie burn between walking and running a given distance. For what it’s worth, though, many runners seem to think the rule-of-thumb comes pretty close.

But what about swimming? Is the “net cost of transport” constant, regardless of speed? Does 2.93 calories per mile, per pound make any sense, even as a rule-of-thumb? I’m inclined to say… no. The reason: Efficiency. Humans are very efficient walkers and runners - it’s what we’re evolved to do. An elite runner converts 90% of energy expended into forward motion - but even a recreational runner is about 80% efficient. (I assume Terry Laughlin got these numbers from science, but I’m not going to hunt for it.)

An elite swimmer, however, is only about 9% efficient And a novice swimmer is astoundingly inefficient – T.L. estimates 3%. Humans are pretty terrible swimmers, all considered.

It makes sense that the “net cost of transport” would be fairly constant on land - because humans efficiently convert additional effort into additional speed. In the water, however, most of our efforts are wasted. Water is both dense (compared to air) and unstable (compared to the ground). Even large increases in effort produce relatively small changes in speed. It would seem to follow, then, that the “net cost of transport” in swimming depends very much on speed! Moreover, skilled swimmers are much more efficient than unskilled swimmers - compared to the relatively small differences among runners. Sun Yang’s net cost of transport is less than mine, and my net cost of transport is far less than the average triathlete.

What else is wrong with 2.93 calories per mile, per pound? Let’s plug in some numbers. In the above quote from Don Macdonald, he uses a 24-mile swim as an example. That happens to be the same distance as the Tampa Bay Marathon Swim. Earlier this year I completed this swim in 8 hours, 59 minutes. Flavia Zappa, the last swimmer to finish, came in at 15 hours, 10 minutes (results link). Assume for the moment that we weigh the same.

If calorie burn is only a function of distance, that means Flavia and I each burned 11,251 calories (2.93 * 24 miles * 160 pounds). In Flavia’s case, that produces a not-unreasonable-sounding (but still high) rate of 742 calories per hour. But for me, 11,251 calories equates to 1,252 calories per hour. Not likely.

Isn’t it obvious that an efficient swimmer will burn fewer calories per mile than an inefficient swimmer? To believe a rule-of-thumb like 2.93 calories per mile, per pound, you essentially have to believe that there is no such thing as efficiency in swimming. Anybody who knows anything about swimming, of course, knows that swim speed is mostly about efficiency.

UPDATE 10/31: Karen raises a great point: Energy expenditure during a marathon swim will also depend on conditions (not just water temperature, as Don Macdonald mentions). Swimming through big swells, chop, and whitecaps will burn more calories than swimming across a glassy lake.

The second in a three-part series. See Part 1. and Part 3.

Calories burned vs. calories consumed

Oct 30 2011

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.

Some basic facts about nutrition in endurance sports:

Lessons learned? Calories consumed ≠ calories burned. Do not attempt to consume 15,000 calories on a marathon swim - unless you’re Penny Palfrey and planning a 50+ hour swim. For a 13-hour swim, you shouldn’t need more than about 3,500 calories. For my longest swim of the year (9 hours in Tampa) I was fine with ~2,800.

And don’t believe anything you read on

(For more, I recommend this book by nutrition scientist Asker Jeukendrup, and also the knowledge base at Hammer Nutrition – e.g., this and this.)

Part 3 in a 3-part series. See Part 2.