What Is a Marathon?
A marathon covers 26.2 miles, or 42.195 kilometers, and that exact figure has been the standard since the 1908 Games in London, when the course ran from Windsor Castle to the stadium at White City. Before that year the distance floated near 25 miles and changed from one race to the next. Organizers stretched the route so the finish line would be in front of the royal box, and the number they landed on became the standard. Every certified marathon run today, from the seven World Marathon Majors down to a small road race in a single town, measures the same length.
The event is at the long end of standard road racing. A runner moves on foot, without stopping, over paved roads that are usually closed to cars, passing aid stations that hand out water, sports drink, and often gels or fruit. Most courses run as a loop or a point-to-point line through a city, and the larger races draw tens of thousands of entrants across every level of ability. The leaders may finish close to two hours while the last walkers come through after six or seven.
Where the Name Comes From
The race takes its name from a story out of ancient Greece. After the Greek army defeated the Persians at the Battle of Marathon in 490 BC, a messenger named Pheidippides is said to have run from the battlefield to Athens to announce the victory, then collapsed and died once he had delivered the news. The account is closer to legend than to documented history, but it tied the event from the start to the idea of running a great distance to the edge of collapse. When the modern Olympics were founded in 1896, the organizers built a long road race around that story, and the marathon has had the name ever since.
The fixed distance came later, because through the early modern races the length varied until the 1908 London course set the 26.2-mile figure that the governing body made official in 1921. The fastest marathon yet recorded is 1:59:30, set by Sabastian Sawe in London in 2026, the first time a man went under two hours in open competition. The quickest women’s time stands at 2:09:56. Those marks are far beyond what almost anyone else can run, since most people who finish a marathon need three to five hours.
The Major Races
Six of the world’s largest city marathons were grouped together as the World Marathon Majors, a series that for years took in Tokyo, Boston, London, Berlin, Chicago, and New York, with Sydney joining as a seventh in 2025. The races draw the strongest professional fields and tens of thousands of amateurs, and runners who finish all six of the original events earn a Six Star medal, a goal that sends recreational runners traveling across continents to collect them one city at a time.
Boston holds a particular place among them as the one major that most runners have to qualify for, by posting a fast enough time at an earlier marathon, a mark set by age and sex and known as a Boston Qualifier. Boston also has a piece of the sport’s history about who was allowed to run at all. In 1967 Kathrine Switzer entered under her initials and became the first woman to run the race with an official number, at a time when women were barred from the event, and a race official tried to drag her off the course while her companions blocked him. Women were not permitted to enter officially until 1972. That history is part of why the race means so much to the runners who reach its start line.
Why the Distance Is Hard
The difficulty comes from how the body stores fuel. Muscles and the liver store carbohydrate as glycogen, and a trained runner has 90 to 120 minutes of it at marathon effort. Most people racing the full distance need three to five hours, which means the fuel on board runs short well before the finish. When glycogen empties, pace drops sharply and the legs turn heavy. Runners call this point the wall, and it often arrives somewhere past mile 20. It happens because the fuel is gone, not because the runner gave up, so the main defense is taking in carbohydrate steadily from the early miles rather than waiting until the damage is done.
Eating while running is its own skill, because the gut handles food poorly under hard effort, and a stomach that has never practiced taking in sugar at race pace will often reject it. Many runners now aim for around 90 grams of carbohydrate an hour, drawn from energy gels made for running and from sports drink, and they rehearse that intake on long training runs so the stomach adapts ahead of time. A written marathon fueling plan sets the timing and the amounts before race morning rather than leaving them to guesswork at mile 18.
Training and the Long Run
Preparation for a marathon runs across months, not weeks. The center of any plan is the long run, a single weekly effort that climbs gradually toward 18 or 20 miles and teaches the body to keep moving on tired legs. Around the long run are easier recovery days, faster tempo work, and a steady rise in total weekly mileage. The last two or three weeks bring a taper, a deliberate drop in volume that lets the body absorb the training and arrive fresh. A first-time runner with a modest base often follows a plan that builds from short runs to the full distance over four to five months, and many of the things that matter most in marathon training come down to consistency rather than any single hard session.
Pacing decides how the second half goes, and the common mistake is starting too fast, riding the early energy and the crowd, then paying for it after the halfway mark. Experienced runners hold an even or slightly conservative pace through the first 20 miles and keep something in reserve for the close. Many large races provide pace groups led by runners carrying signs for a target finish time, which gives newer entrants a steady rhythm to sit behind. Conditions matter as much as fitness, since heat, humidity, wind, and hills can add many minutes to the same runner’s time.
Reading a Marathon Result
Two times matter on race day, because gun time starts when the race begins while chip time starts when a runner crosses the start mat, which can be minutes behind the line in a crowded field. Personal records are measured by chip time. A result of DNF means a runner did not finish, while DNS means they did not start. A negative split, running the second half faster than the first, is the mark of good pacing and steady fueling.
The marathon has a particular pull in endurance sport because the distance asks for both speed and patience over a span long enough to expose any weakness in fitness, fueling, or pacing. Finishing one, at any time, marks a real level of preparation. A fixed historic distance, a demanding physical test, and a set of famous races with deep history have kept runners coming to the start line for more than a century.