Lessons from the Iditarod: How sled dogs run 1,100 miles through the harshest conditions

On those cold mornings here in, ummm, California, when I find it daunting to face a mile-long walk in the rain with two frisky sighthounds, it's hard to imagine having the stamina to run more than a thousand miles in less than two weeks, pulling a sled, during freezing temperatures, blizzards, and heavy winds.



So how exactly do sled dogs do it, and can humans learn anything from them that might help us get our butts in gear a bit more effectively for our lesser challenges?



At this week's American Physiological Society conference on the biology of exercise, Dr. Michael Davis of the Oklahoma State University’s Center for Veterinary Health Sciences shared a few "Lessons from the Iditarod” with his peers in the human health field:

Racing sled dogs are best known for their “mushing” each March during the Iditarod Trail Sled Dog Race, the world’s longest sled race. They are the premier ultra-endurance competitors, covering 1,100 miles from Anchorage to Nome, Alaska, sometimes in just nine days. It is unclear how they can keep running, despite heavy blizzards, temperatures as low as –40°F, and winds up to 60 mph. No other animal has been found to come close to the physiological attributes these dogs display.

How do they do it? In a number of ways.



First, sled dogs, unlike humans, rapidly adapt to intense exercise. Although the first few days of the race put an enormous strain on their endurance, after four days of this level of extreme activity they've returned to almost the same metabolic state as they were before the race began, without a period of rest. Humans performing extreme activity, instead, are in a depleted state that can require as much as a full day for recovery. This rapid adaptation is key to their extraordinary endurance.



Second, racing dogs have around twice of the aerobic capacity of non-racing dogs.



Third, forget the carbo-loading. When it comes to extreme endurance in canines, fat is where it's at:

During periods of racing, sled dogs can burn up to 12,000 kilocalories per day (kcal/day). This means that a 55-pound sled dog will consume the equivalent of 24 McDonald’s Big Macs to fuel their run on any given day. Some of the running dog’s high-fat diet is converted to energy in the liver, and used as fuel in the initial stages of exercise. Preliminary data suggests that this process is a desirable trait intended to efficiently support exercise in the racers. It is worth noting that humans would need 72 Big Macs to fuel the power they need to make a day’s run, assuming their body could absorb and process all the fat contained in the beef.

Is there more? Experts believe so.

Dr. Davis theorizes that it may involve the regulation of extremely thin membranes in the muscle fibers and changes in the cells that are responsible for the body’s energy production. “These are one-of-a-kind athletes. What we learn from them will undoubtedly tell us a lot about human performance as well.”

Read a summary of Dr. Davis' presentation here. Me, I gotta go pry my dogs off the sofa for a little walk.



Photo by Brendan McKiernan of Rogue River, OR, a veterinary internist involved with some of the studies. Used with permission.

Comments

[H. Houlahan]

People don't believe me when I tell them that distance-racing Alaska huskies are far and away the greatest athletes on the planet, any species, ever.



Just their ability to convert food calories into energy would qualify them on that score. (It rivals the ability of the alien mutant broiler hybrid chickens to convert food calories into meat.)



But that they do it while covering some of the harshest ground on the planet -- I am, and will always remain, in awe.

[H. Houlahan]

The CITIZENS of Alaska, when asked, voted NO on aerial slaughter of wolves in 2000.



And there was no such thing under Governor Knowles.



But politicians such as Palin and Jail-Bait Murkowski just kept circumventing the mandate of the referendum.



In 2008, there was ANOTHER referendum (hey guys, didn't we vote on this before?), and Palin pumped $400K of state money into a propaganda campaign to defeat it, and introduced legislation that would prohibit Alaskans from holding referenda on wildlife issues!



Palin's bounty came up because not enough "hunters" are interested in slaughtering wolves from the air.



Democratic process = FAIL.



But it is one issue that could persuade me to boycott the Iditarod coverage.

[Anne T]

Any well conditioned dog, who can pursue it's working function, from moving sheep from pasture to pasture, chasing and catching live prey over or under various difficult terrains, pulling a sled in horrific winter conditions or holding an angry steer by the nose for the butcher just blows me away. To see a dog as an athlete, doing the job his type was bred for, is an awesome thing.

What the studies will tell us is that for generalists, we as a species aren't bad since we can do such a huge variety of tasks, but we will never achieve what a sled dog does no matter how many drugs we take unless we deliberately breed for it. That's what we have done with dogs, at least in the beginning before the advent of kennel clubs and breed standards; select for a specific set of skills, and breed for them. And as we all know, that selection has led to it's own sets of genetic problems.

Perhaps studying what makes sled dogs or salukis or border collies do what they do so well may lead us to a better understanding of how the mammalian body/brain works, but it won't help us better ourselves unless we undergo a gargantuan philosophic shift about our own hodge podge breeding practices. And that ain't going to happen.

[Shannon Watts]

There are many Northern breeds capable of mushing but I believe one of the oldest is the Siberian husky. Siberians have been a distinct breed for thousands of years alongside the Chukchi people. While the Chukchi certainly bred for specific characteristics, they also lived a very hard life so weak animals didn’t survive. The result is a very hardy breed with few genetic defects (recommended to screen eyes and hips although the OFA ranks them 143/150 for risk of hip dysplasia). Since reindeer were used for heavy loads, the dogs were bred for speed and endurance with minimal food. Siberians are smaller than other northern breeds. Since the dogs were part of the family, they have a sweet and amiable temperament. Another interesting point, the Chukchi believed heaven was guarded by two Siberian huskies. Anyone who mistreated a dog can’t get in!

[Joy]

I feel sad for the Iditarod dogs who are kept on chains their whole lives except for when they are training/racing. Someone once told me that's just the "culture" of it...but I still feel bad for the dogs.

[redstarcafe]

Sled dogs good; wolves bad. It puzzles me that the home of the Iditarod promotes aerial hunting.

[paula recchia]

The citizens of Alaska don't seem to be able to influence the elimination of aerial wolf hunting but tourists can by putting and keeping the pressure on!