Two weeks after moving to Alaska in August 2014, Larry Daugherty, now 44, met well-known Iditarod musher Jim Lanier at a book signing.
Almost six years later, on Saturday, March 7, Daugherty will compete in the Iditarod Trail Sled Dog Race for the fourth time. The event features the best mushers in the world in tandem with their teams of 14 dogs, and over the course of nine to 12 days, competitors traverse through nearly 1,000 miles of treacherous terrain from Anchorage to Nome (roughly the same distance as Los Angeles to Portland). To date, Daugherty’s best finish is 10 days, 18 hours, 29 minutes, and 10 seconds. This time around, Daugherty is running a “B team” from a larger kennel so those dogs can get some racing experience. They’re on the younger side, but the hope is by next year, they’ll be on the varsity squad for an Iditarod champion.
I’m taking my daughter and her friends up Mount Rainier this summer. Then in June 2021, my son wants to climb Denali for his senior trip, and we’re training to do that together. I’ve already climbed it once before. After that, I have a few more of the Seven Summits to do. From an adventure standpoint, those are my big goals right now.
Sleep deprivation. That’s really the hardest part. I usually stop for six hours at a checkpoint, which is considered a large amount of rest; the elite mushers will take between two and four hours at a checkpoint. At least two hours of that time is spent taking care of the dogs and melting snow to get water. Taking care of each and every paw. Rubbing sore muscles. Just really obsessing over the health of the dogs so they can get you through this thousand mile adventure. You just dont get a lot of sleep. You also cant plan on storms that are going to hit and how that might affect your race plan.
Like Daugherty, Lanier trained at the Mayo Clinic and worked in medicine. They hit it off immediately. Daugherty considered it fate—he’d always dreamed of coming to Alaska and of dog sledding there. Lanier told him to stop by his kennel sometime. Daugherty went the next day, and kept showing up afterwards.
Within 10 days of the ceremonial start in Anchorage, all 14 dogs selected for the final team receive a comprehensive physical exam by a veterinarian either at the pre-race vet check-in in Willow, Alaska, and/or by their personal veterinarian. All dogs are microchipped so they may be tracked from pre-race to finishing under the Burled Arch in Nome.
There are mandatory 8-24-hour long stops required throughout the race. During those stops, complete physical exams are conducted by the veterinarians. Most veterinarians on the trail come from either surgical and/or emergency and critical care practices. Due to our daily exposure to orthopedic and emergency cases, we are comfortable with the common issues faced by these canine athletes on the trail. We work with the mushers to resolve any concerns and are there to offer support to any dog that may require more intensive medical management.
Dr. Tonya Stephens attended Texas A&M University, completing an undergraduate degree in animal science and Master of Science in exercise physiology. During her time at TAMU, she also completed an externship at the British Horseracing Authority (British equivalent to the American Jockey Club). She then attended the University of Florida, where she completed her Ph.D. and lectured in nutrition and exercise physiology. A passion for research led her to pursue a DVM. While in veterinary school, she was introduced to and instructed by Dr. Huisheng “Shen” Xie in traditional Chinese Medicine. Based on the research conducted at U of F and outcomes from cases treated in this manner, she completed practical and coursework to become a Certified Veterinary Acupuncturist. Upon returning to Texas, she completed her studies in alternative therapies with Parker University becoming American Veterinary Chiropractic Association certified. Dr. Stephens is currently the Tarrant County Veterinary Medical Association president and volunteers each year for the Iditarod.
Dr. Stephens: Health of the dogs is the number one priority during the Iditarod, and a team of veterinarians works to provide dog care for each participant before and during the race. A month before the race, all dogs that are selected by the musher (up to 24) undergo an electrocardiogram (ECG) and screening blood work. The results are reviewed by a boarded cardiologist and an internal medicine specialist. This ensures all athletes are clear of any obvious preexisting conditions that could compromise their ability to compete.
Dogs in the race can ingest snow along the trail, as well. This is called “snow dipping” and is more prevalent in the warmer races, during which the temperature is at the freezing point or just above. Many mushers will also offer free choice water at checkpoints or melt snow on the trail.
Nicolas Petit feeds his dogs before they leave Unalakleet during the Iditarod Trail Sled Dog Race on March 10, 2019. (Marc Lester / ADN archive)
In certain snow conditions, leggings keep snow and ice from freezing in clumps onto the dogs’ fur.
Dubstep, a dog in Merideth Mapess team, is covered in frost after arriving in Nikolai on Wednesday, March 11, 2020 during the Iditarod Trail Sled Dog Race. (Loren Holmes / ADN)
Also, not all coats are created equal. Some of them are more like windbreakers, without insulation, and help to counteract the dehydrating effects of a tailwind. Some coats, made of thin white fabric, are actually designed to keep the dogs cooler on bright, sunny days (particularly for dogs with dark fur). Again, there’s no real rule of thumb; it all depends on what each musher knows about their team.
Like many things in mushing, this varies significantly by team (and by dog), and the calculation is more art than science; a musher decides about coats based on not just air temperature but wind direction, wind speed, fur thickness, the dogs’ body mass and so on. And because Alaskan huskies are such a variable breed, dogs from one lineage may need coats long before their fluffier cousins.
How to Feed Sled Dogs
“It is so instinctual to be doing what these dogs are doing…” Iditarod contestant and avid musher Mike Santos believes, “…That it really requires very little training.” Dogs love to run. Still, a musher’s challenges are daunting. Alaskan weather is fierce and unpredictable; handling logistics, supplies, the vagaries of trail conditions, and– perhaps most of all– knowing the capabilities of yourself and your team are vital for every racer. Santos chooses his sled dog team carefully. “Just like people, they are all suited to different temperatures, different trail lengths, team size,” &c. Mike Santos owns Wolf’s Den Kennel in Cantwell, Alaska, which houses about 65 dogs.
Every sled dog racing the Iditarod Trail Sled Dog Race consumes roughly 12,000 calories daily, the equivalent of 24 McDonald’s Big Macs. Yet they weigh only about 40-60 pounds [18-27 kilograms]. That makes sled dogs powerful calorie burners; in contrast, human athletes struggle to put away more than 5,000 calories in one day despite weighing in at roughly three times as much as a racing sled dog. Long-distance canine racers typically burn 240 calories per pound of weight every day, while a high-performance human athlete, a Tour de France cyclist, would typically burn only 100 calories per pound of weight daily.
Iditarod Trail Sled Dog Race, the world’s longest sled race, takes teams of canine athletes and human mushers along a grueling 1,100 mile [1770 kilometer] long trail from Anchorage west to Nome, Alaska. Wild weather is the norm. and every team can anticipate blizzards, ice and fog, screaming winds strong enough to tip sleds and temperatures as low as -40°F [-40°C].
Teams are composed of 12 to 16 dogs, and there must be at least 6 dogs pulling the racer’s sled at the finish line.
Mushers provide careful care for their dogs, dressing paws and groins to protect against ice as needed, keeping the dogs hydrated, and feeding them a mixture of meat, fish, and commercial dog food (typically 60% fats, 40% carbohydrates and proteins). Checkpoints are set up along the way where mushers check in, dogs rest, and veterinarians sign off on the health of every animal.
It’s quite a trek. Today, March 11, 2014, Dallas Seavey won the 2014 Iditarod (Willow to Nome, 1,000 miles) in 8 days, 13 hours, 4 minutes, 19 seconds.
Alaskan huskies and other long-distance racing dogs are mighty endurance athletes. These sled dogs can run an average of eight miles per hour, traversing over 100 miles per day.
The secret to the dogs’ mighty endurance, and their calorie-burning capabilities, lies in their powerful and unusual metabolism.
When we say metabolism, we reference bodily processes that convert or use energy. Think digestion, muscle use, blood circulation, breathing, and the functioning of nerve networks and the brain, and much more. Metabolism includes catabolism that breaks down i.e. nutrients into energy, and anabolism, which uses that energy to construct things we need.
We gain energy from catabolism. Proteins are broken down into amino acids and can be converted into other compounds– used to make glucose, for instance. Glucose is carried by the blood stream. It is also stored in muscles and in the liver as glycogen, which is a complex carbohydrate. Any extra energy that humans get from metabolism is stored either as glycogen or as fat.
Glycogen is useful; it is very important to the function of muscles. Muscles use glycogen as fuel to power physical activity.
Heavy exercise prompts muscles to use glycogen. As human endurance athletes exercise they burn calories, deplete their glycogen and thus their muscular energy reserves, and stress their bodies. Marathon runners and athletes undergoing intensive training diminish stores of glycogen and protein, build up lactic acid, and eventually become fatigued at which point they must rest and recover until their stores are replenished.
Dogs normally metabolize energy as explained above. Long-distance endurance runs, however, cause sled dogs’ metabolism to radically alter. It has been compared to throwing a metabolic switch. Veterinarian Michael Davis, Oklahoma State University Center for Veterinary Health Sciences, has been investigating the phenomenon since 2001.
“Before the race, the dogs’ metabolic makeup is similar to humans. Then suddenly they throw a switch — we don’t know what it is yet — that reverses all of that,” Davis explained. “Dogs will go from using their reserves to not.” In 24 to 48 hours, endurance-conditioned sled dogs “Change their metabolism so they don’t use up their reserves anymore.” Within four days the dogs can “Go back to the same type of metabolic baseline you see in resting subjects. But it’s while they are running 100 miles a day.”
Despite consecutive days of strenuous exercise, the dogs don’t become fatigued like human endurance athletes do. Instead, they rapidly adjust to the demands of running the race. This physiological capability makes sled dogs the perfect athlete for the Iditarod.
Davis said, you can “Take dogs out and you run them 100 miles per day today and tomorrow and the next day, and they come back, sleep, eat, do it again without having any outward sign of it mattering.” In fact when the dogs run in more than one strenuous race in the season “They don’t just continue to perform, they perform a lot better.” Davis pointed out “They can do it indefinitely, as long as you have trail and they’ve got food. They get tired, but they don’t fatigue in the biochemical sense.” They are essentially fatigue proof.
Dr. Davis has been analyzing blood and muscle samples from long-distance running canines in Alaska to try to discover what flips that metabolic switch. Humans could benefit deeply from the discovery. Imagine: greater endurance for athletes, avoiding fatigue for i.e. armed forces, and perhaps even benefits for diabetics and another tool in the fight against obesity. Davis speaks of the dogs: “They have a hidden strategy that they can turn on,” and “We are confident that humans have the capacity for that strategy. We have to figure out how dogs are turning it on,” in order “To turn it on in humans.”
Long-distance canine athletes have powerful lungs and circulatory systems which are capable of delivering plenty of oxygen to their muscles. The ratio of the volume of oxygen delivered to the body’s weight per minute is called aerobic capacity. An elite human athlete’s aerobic capacity is something like 60-80 ml/kg/min Vo2max. An untrained sled dog’s is 175 ml/kg/min VO2max. A trained and racing sled dog’s average aerobic capacity is roughly 300 ml/kg/min VO2max. That great ability to move oxygen to the muscles that need it lends itself well to a sled dog’s repertoire.
Glycogen, the complex carbohydrate compound which stores energy to supply to muscles, is utilized by the sled dogs at first. After the metabolic switch is flipped in racing dogs the animals use a glycogen-sparing metabolism instead. Their glycogen stores replenish as opposed to becoming depleted. Instead of converting proteins or fats into glycogen, they seem to be pulling fat from their bloodstream into their cells and utilizing it for energy. Davis’ findings suggest that the canines are directly burning fat.
It might be made possible by the dogs’ surplus of mitochondria: cellular power plants. Dogs have roughly 70% more mitochondria per cell than humans have. Davis speculates that the canines are extracting fat from the bloodstream and somehow moving it into the mitochondria of their muscle cells. We’re not certain how that transportation takes place, but the hormone insulin seems to play an important role. With their high-fat racing diet, the use of fat for energy, and their numerous mitochondria, dogs can obtain and burn fuel very efficiently.
“The faster you can get stuff into a muscle cell, the faster you can use it,” Davis said. When the switch is thrown, “They may get better at pulling fat out of the bloodstream on the fly.”
Transporters are proteins that move fatty acids, glucose and complex carbohydrates from the bloodstream across cell membranes and into the mitochondria power plants. Davis is hard at work decoding the mystery of the canines’ transporters; normally dogs use transporters similar to the ones humans use, but not during endurance races like the Iditarod. “Something is transporting the fat into dog muscle,” he said, “But it isn’t the transporter that we [humans] use.”
Congratulations to Dallas Seavey, winner of the 2014 Iditarod Trail Sled Dog Race, and to all contestants entered. As always, navigating trail conditions involved much more than “Gee” (left turn) and “Haw” (right turn). In Alaska, “Changes in weather can occur almost instantaneously because of geography or just because of wind change,” musher Mike Santos noted. This year proved challenging because of unusual warmth and stretches of bare ground, but that’s not to say the mushers didn’t run into blizzards and icy tundra. “The Iditarod is always challenging,” Santos said, and “I think you would be very foolish to sign up for the Iditarod and not expect to have a pretty big challenge ahead of you.” Of course, it’s a challenge that he and other mushers relish.