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Learning Fat-Burning Secrets from Sled Dogs

Cracking the metabolic secrets of distance-racing canines















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A Challenge to Canine Health
The rigors of the Iditarod sled dog race, in which a musher and a team of 12 to 16 dogs cover some 1,150 miles in 16 days, takes its toll on the health of its athletes. On average, three dogs die every year in the race; 2009 saw double that number. Some animal-rights groups have criticized the event as cruel. And in this age of juiced jocks, some observers also wonder if steroids are involved.

To monitor the dogs’ health and watch for performance-enhancing drugs, volunteer veterinarians keep watch during runs. At the Iditarod, for example, a dedicated plane follows the canines and samples urine of dog teams for drugs without warning. Mushers must carry sick or injured dogs to the next checkpoint for treatment and continue the race without that canine. They must finish with at least six running dogs.

Note: This article was originally published with the title, "Sled Dog Science".



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ABOUT THE AUTHOR(S)

Krista West lives in Fairbanks, Alaska, with a dog-chasing cat.


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  1. 1. PsySciGuy 10:29 AM 5/29/09

    Those of us humans living in cold climates - like South Dakota - experience a similar effect every fall. Our internal furnace "turns on." After adding layer after layer of clothing and blanket after blanket as the weather cools, we suddenly throw off the covers and put our sweaters back in the closet. We also develop a craving for fat. Could both our "furnace" and the dog's endurance be mitochondria mediated?

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  2. 2. SledDogAction 10:42 AM 5/29/09

    Dr. Davis findings about dogs becoming robotic-like while running in the Iditarod dont square with the documented facts about how the dogs behave. The following are just a few examples of dogs refusing to run. According to the Associated Press, in the 2007 Iditarod, eyewitnesses reported seeing musher Ramy Brooks kicking his dogs and beating them with a chain when they wouldnt run. A May 22, 2007 editorial in the Anchorage Daily News said, Rare is the musher who hasnt lost it with his or her dogs. Ramy Brooks isnt the first and wont be the last. Steve Fossett wrote in his memoir Chasing the Wind that he bit his lead dogs right ear when he refused to keep running. Iditarod race winner Joe Runyan recommends shocking dogs with a cattle prod when they refused to move.

    Iditarod dogs arent machines. They dont want to run when they are sick or injured. What happens to them during the Iditarod includes death, paralysis, frostbite of the penis and scrotum, bleeding ulcers, bloody diarrhea, lung damage, pneumonia, ruptured discs, viral diseases, broken bones, torn muscles and tendons, vomiting, hypothermia, sprains, broken teeth and torn footpads.

    The dogs dont want to run when trail conditions are horrid. For instance, in 2007, Shain Perrins told the Alaska Public Radio that Dogs arent wanting to go, because they are going right into the wind. Its probably blowing, gusting up to 50 miles an hour in the valley.

    Dogs dont want to run when theyre tired. They routinely suffer from anemia which exhausts them. Kathie Davis told the Spartanburg Herald-Journal that one of her dogs fell asleep in the middle of a run. Martin Busers dog Quebec vanished from his gangline while he was on the move - and Buser had failed to notice. Buser found Quebec curled up in the snow to nap, right where hed come loose.

    In Anchorage, several years ago, a mushers dogs got loose from his truck. They didnt run over 1,000 miles to Nome. They didnt even run to the outskirts of the city. They were found curled up, sleeping on peoples lawns about ten blocks from where the mushers truck was parked.

    The blood tests dogs receive do not detect all the performance enhancing drugs they may be given. The dogs are not tested for all the common drugs. And there are so many new drugs, including synthetic versions, that its even hard for testers of humans to keep up. But even knowing what drugs to test for isnt enough. Gene doping works on dogs and its impossible to detect.

    Margery Glickman
    Sled Dog Action Coalition, http://www.helpsleddogs.org

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  3. 3. Evelyn 11:26 AM 5/29/09

    Margery -
    While your concerns are certainly valid, this article isn't really about the ethics of dog racing, and nowhere does it mention the dogs becoming 'robotic-like'.

    Instead, it focuses on an interesting biological phenomenon that happens in these dogs internally, and what the discovery of this mechanism could mean for science.

    Regardless of the ethics involved, it is fascinating that these dogs have developed a way to work their muscles without the muscle becoming tired. Beyond dieting, this would certainly have interesting implications for athletes and other humans involved in labor-intensive jobs. Think about...marathon runners who don't get tired for days!

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  4. 4. SledDogAction 03:52 PM 5/29/09

    Evelyn,

    The dogs do become tired. You should have read what I wrote. In part, anemia tires the dogs. Read below:

    http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16034156&query_hl=3

    1: Biol Trace Elem Res. 2005 Summer;105(1-3):87-96.

    Sustained strenuous exercise in sled dogs depresses three blood copper enzyme activities.

    DiSilvestro RA, Hinchcliff KW, Blostein-Fujii A.

    Human Nutrition, The Ohio State University, Columbus, OH, USA.

    Studies show mixed conclusions about acute responses of copper status to strenuous exercise. Because copper function involves metalloenzyme activities, which might take days to change, the present study examined the response of three copper metalloenzyme activities to sustained strenuous exercise in sled dogs. A race lasting 12-15 d depressed activities for both plasma ceruloplasmin and erythrocyte superoxide dismutase in dogs consuming commercial dog foods and meats. A shorter, 3-d training run for dogs fed a commercial balanced diet also depressed ceruloplasmin activities but not superoxide dismutase activities. Dogs fed the same diet but that did not run showed no changes in either parameter. Activities of a third copper enzyme, plasma diamine oxidase, also decreased after a 3-d training run. In summary, blood activities of three copper enzymes were depressed by sustained strenuous exercise in sled dogs.
    -------------------------------------------------------------------------------------------------------------------------

    According to the National Academy of Sciences Board on Agriculture & Natural Resources, copper is a helper in enzymatic reactions. The function of copper includes: Connective tissue formation; iron metabolism; blood cell formation; melanin pigment formation; myelin formation; defense against oxidative damage. Anemia is a sign of a copper deficiency.

    - Board on Agriculture & Natural Resources, National Academy of Sciences, website, 2005, http://dels.nas.edu/banr/cd_dog_vit.html

    While the article by Krista West doesn't portray the dogs as being robotic-like, Dr. Davis has described the dog this way.

    Margery

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  5. 5. jon winchester 12:40 AM 5/31/09

    Some dogs get tired. Some don't. Some love running and winning. Loving it or not, some run themselves to death, or are forced to. (We see the same range of conditions in humans who run endurance events.) Whether that's right or wrong was not the subject of the article and I don't think this is the forum for it. The ability of some dogs to run without tiring is the subject of this article. It's fascinating and very relevant, since they are mammals whose cellular biochemistry is essentially the same as ours. The "robot" or "machine" simile is appropriately used in admiration of an athlete whose performance seems beyond what a biological organism could be capable of.

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  6. 6. Lee in Michigan 10:59 AM 9/20/09

    Scientific American is a prestigious journal and requires it's authors of articles to have credentials. What are Krista West's credentials and why were they not posted under her name in the article?
    Lee in Michigan

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