“This Is a Marathon”: The Demands of Biathlon From an Endurance Sport Perspective

Watching the men’s 20km individual biathlon at the Anterselva Biathlon Arena during the Milano Cortina Olympics this morning, I hear the announcer say it out loud: “This is a marathon.”

It is a curious choice of words.

Because what is unfolding on screen looks nothing like a marathon in the traditional sense. There is no steady rhythm, no quiet accumulation of miles. Instead, there are violent surges up snow-packed climbs, full-body skiing at near maximal effort, and abrupt stops into silence, rifle raised, breath controlled. Then off again. Over and over.

Then the announcer adds, almost matter-of-factly: “The lungs cannot get enough oxygen, the legs are burning.”

This is biathlon.

And it might be one of the most misunderstood endurance events in the world.

Biathlon combines two radically different demands. Athletes must ski hard enough to push heart rates close to their ceiling, then immediately suppress tremor, breathing, and nervous system activation to hit five small targets. Miss, and time is added.

From a physiological perspective, this creates a uniquely brutal environment.

Biathletes operate with aerobic capacities comparable to elite Nordic skiers. They rely heavily on upper body endurance. They tolerate repeated spikes in lactate. They must then regain fine motor control while hypoxic and fatigued, downshifting their nervous systems from full fight or flight into calm focus within seconds.

Most endurance sports allow athletes to stay in one mode. Biathlon does not. This switching is what makes the sport so difficult to master and why it earns a reputation as one of the toughest events in the Winter Games.

When commentators call it a marathon, they are not talking about distance. They are talking about the difficulty of the endurance challenge.