Nearly 5,000 miles away in the mountains of North America, radios crackle with chatter from a wildfire incident command post, air operations and other crews fighting a wildfire. Up the fireline, the swings of Pulaskis, axlike hand tools, are carving a fuel break into the land. The weather forecast predicts a high of nearly 100 degrees Fahrenheit (38 C) with wind, a combination that can push the fire high up into the canopy of dense lodgepole pines on the mountainside.
The yellow jerseys here are sooty, sweat-stained and flame-resistant, with a strong, earthy odour. Hotshot crews like this one are the elite workforce of the forest, and the demand on their bodies can rival that of the cyclists in the Tour de France, as recent research shows.
On this morning, the Hotshot crew has already hiked 3 miles up steep, uneven terrain and built nearly 1,200 feet of fire line. It is not yet 10 a.m. The day is just beginning, the first day of a 14-day rollout.
Measured with the same techniques used to quantify the energy demands of Tour de France riders, wildland firefighters demonstrate an average total energy expenditure approaching 4,000 to 5,000 calories per day. Some days can exceed the Tour’s average of about 6,000 calories. Add to that a daily water need of 1.5 to over 2 gallons.
This isn’t just for a few days. Fire season in the western United States can last five months or more, with most Hotshot crews accumulating four to five times the number of operational days of the 22-day Tour de France and over 1,000 hours of overtime.
Every year, on average, about 60,000 wildfires will burn across roughly 70 million acres in the western U.S. Drying grasses and forests create fuel for the spark of a lightning strike, power line or carelessly abandoned campfire, and windy summer weather can spread that into a blaze. When those fires could threaten communities, the Hotshots are mobilized.
Impact on the wildland firefighter’s body
As the work shift progresses, the Hotshots constantly monitor their surroundings and self-regulate nutrient and fluid intake, knowing their shift will last 12 to 16 hours. During intense activity in high heat, their fluid intake can increase to 32 ounces per hour or more.
The highest-intensity activity is generally during the early morning hike to the fire line. However, the metabolic demands can sharply increase if crews are forced into a rapid emergency evacuation from the fire, as more than 25 years of wildland firefighter physiology research shows.
The most effective way for wildland firefighters to stay fuelled is to eat small meals frequently throughout the work shift, similar to the patterns perfected by riders in the Tour. This preserves cognitive health, helping firefighters stay focused and sharp for making potentially lifesaving decisions and keenly aware of their ever-dynamic surroundings, and boosts work performance. It also helps slow the depletion of important muscle fuel.