What Is an Ultramarathon?
An ultramarathon is any running race longer than the marathon distance of 26.2 miles. The most common ultra distances are the 50K, the 50-mile, the 100K, and the 100-mile, though many events measure their challenge in time rather than distance, such as a 24-hour race or a backyard ultra where runners complete a set loop every hour until only one remains. Most ultras are run on trails through mountains, forests, or desert, which adds climbing, rough footing, and changing weather to the basic demand of covering a very long way on foot.
The jump from a marathon to an ultra changes the nature of the effort. Where a marathon is run at a sustained, uncomfortable pace, an ultra is run at an effort a person can hold for many hours, which for most runners means a steady jog on the flats and fast hiking on the climbs. Finishing times stretch accordingly, so a 100-mile mountain race can take the leaders 15 to 24 hours and many finishers close to a day and a half, with runners moving through one or two nights without sleep.
Where the Sport Began
Long-distance foot races are old, and the Comrades Marathon in South Africa has been run over about 90 kilometers since 1921, but the modern trail ultra traces much of its identity to a single run in California. In 1974 a man named Gordy Ainsleigh entered a 100-mile horse race through the Sierra Nevada, the Western States Trail Ride, but his horse went lame before the start. Rather than drop out, he set off on foot and covered the 100 miles from the mountains to the town of Auburn in a little under 24 hours, proving a person could finish inside the time limit set for horses. A formal running race grew from that effort and was founded in 1977, becoming the Western States 100 and the template for mountain hundred-milers that followed.
From there the sport spread into a calendar of races with their own characters. The Ultra-Trail du Mont-Blanc circles the highest mountain in the Alps over about 170 kilometers with enormous climbing. The Badwater 135 crosses Death Valley in the heat of July, starting below sea level and finishing partway up a mountain, and many call it the hardest foot race for its conditions alone. Each event tests something different, from altitude and cold to relentless heat.
How an Ultra Is Run
Ultras are built around aid stations, points along the course stocked with water, food, and electrolyte drink where runners refill bottles and eat. At longer events runners are often allowed a crew, a small team that meets them at access points with supplies, and a pacer, a companion who runs alongside through the later miles to keep them moving and alert. Drop bags let a runner stash gear and food at points they cannot reach by car. Cutoff times set the pace a runner must hold to stay in the race, and missing one ends a runner’s day.
The running itself looks different from a road race. Climbs steep enough to force a walk, descents that batter the legs, roots and rocks that demand attention with every step, and stretches run by headlamp in the dark all add to the basic task of covering the distance. Many runners carry trekking poles for the climbs, layers for the cold of night, and a light for the dark hours. The skill of an ultra is less about speed than about managing the body and the long hours so a runner reaches the finish still able to move, and sleep deprivation becomes its own obstacle on the longest events.
The Backyard Ultra
The backyard ultra reduces the sport to one rule, invented by the race director known as Lazarus Lake, where runners complete a loop of 4.167 miles every hour, on the hour. The odd distance is deliberate, since 24 loops add up to exactly 100 miles in a day. A runner who finishes a loop early can rest, eat, and gather themselves, but has to be back on the start line when the next hour begins. The race has no set finish, and it simply continues, hour after hour, until one runner completes a loop that nobody else does, and that last runner is the only finisher. Everyone else is recorded as not finishing, no matter how far they ran. The format can stretch across multiple days, turning the race into a test of who can keep going longest rather than fastest.
Fueling the Long Effort
Fuel matters more to the outcome of an ultra than raw fitness. Over many hours the body burns through far more energy than it can store, so a runner has to eat steadily from early in the race to keep going. The intake often climbs toward 90 grams of carbohydrate an hour on the harder efforts, drawn from gels, drink mix, and real food such as potatoes, broth, and fruit that the gut can still handle when sweet flavors stop appealing. Learning how to fuel across an ultra is a skill that takes practice, since a stomach that rebels late in a long race can end it as surely as tired legs.
Hydration and sodium matter as much, because a runner sweating for hours loses a large amount of electrolytes, and replacing them prevents the cramping and nausea that derail so many first attempts. Pacing the effort low enough to keep eating and drinking, rather than racing hard early, is the habit that separates finishers from those who fade, and the best ultrarunners share a set of habits built around patience and steady fueling rather than raw speed.
Why People Run Them
The appeal of an ultra differs from the appeal of a fast road race. Time and place matter less than the act of covering ground that seems beyond reach, and the experiment of finding out what a body and mind can do over a day of continuous movement. Many runners come to the sport after years of road racing, drawn by the mountains and the slower, longer test.
The distances can sound impossible to someone who has only finished a first marathon, yet the path into the sport is gradual. Most runners start with a 50K, not far beyond the marathon, and build up over seasons. What they find is a form of racing where managing fuel, terrain, and the long hours of the mind becomes the real challenge, and where simply reaching the finish stands as the achievement.