A fartlek run involves alternating between a faster pace and a slower pace during a run. This method of training increases endurance and helps the body adapt to exercise. Fartlek runs can also be motivating, as they mimic the experience of a road race while training.

Fartlek runs can be short or long, on hilly or level terrain, and can also be done on a treadmill. Because there are is no set time or pace, fartlek runs are a great option for beginners.

Beginners should start slow and increase the intensity over time. It is important to follow the guidance of an exercise physiologist or certified running coach to better understand how this method works and how to do it correctly.

Main benefits

The main benefits of a fartlek run are:

1. Increasing endurance

One of the main characteristics of a fartlek run is the variation in speed and distances covered during the run, alternating between stretches of greater and lesser intensity. This variation can help increase endurance and improve cardiovascular functioning.

2. Creating a road race experience

By switching up the pace during a run, the fartlek mimics the experience of running a road race, where you cannot have total control over your pace or heart rate at all times. A road race can also introduce obstacles like bridges, hills, and curves that force you to adjust your speed.

3. Being easy to incorporate into any run

Fartlek training is easily incorporated into both long and short runs, with or without hills. It is particularly easy to choose specific moments to increase or decrease the intensity when you are running on a treadmill or on flat terrain.

One way to do this is to choose certain markers, like a park bench, and speed up when you pass the first bench and slow down when you pass the next one.

4. Increasing self-awareness

Fartlek runs help people better understand their mental and physical capabilities and challenge the body to adapt to variations in distance and speed.

5. Being a good option for beginners

Fartlek runs are especially good for beginners because the runner is free to change up the pace during their workout based on their level of fitness and ability.

Check out this beginner running plan.

Interval training vs. fartlek

Interval training involves short bursts of high-intensity running followed by a recovery period. Intervals can be based on distance or time. One example of interval training would be: run 500 m (0.3 mi) at maximum speed, with 1 minute of rest in between. Do this 8 times.

Fartlek training, on the other hand, involves more continuous running, during which you switch up the pace over various distances. For example: run 300 m (0.2 mi) at a moderate pace + 400 m (0.25 mi) at a faster pace + 200 m (0.1 mi) at a slower pace + 600 m (0.4 mi) at a moderate pace. Do this 3 times, resting for 2 minutes between circuits.

Whether interval training or fartlek, it is important to work with an exercise physiologist or certified running coach to develop a training strategy based on your individual goals and fitness level.

Getting started

The following are step-by-step instructions for how to do a fartlek run:

Warm up for 15 to 20 minutes before your run;
Identify landmarks for speeding up and slowing down, like telephone poles, street signs, or trees for outdoor runs;
Start your run at your normal pace, until you reach the first marker;
Increase your speed at the first marker and maintain it until you reach the next marker;
Maintain an easy pace after more intense intervals to allow for recovery;
Return to your normal pace after catching your breath, until you reach the next marker;
Finish your workout by stretching for 10 to 15 minutes to help with muscle recovery.

People who are just getting started should aim for 5 to 6 intervals of increased intensity during their run. This number can be increased gradually over time with the help of a certified coach or trainer, until reaching a goal of running for a total of 60 minutes.

Heart rate can be monitored during a fartlek run but is not required. People who are monitoring their heart rate should not exceed 90% of their maximum heart rate and should slow down briefly if this happens.

Using a treadmill

A fartlek run can also be done on the treadmill. In this case, people can use the timer on the treadmill or even television commercials to know when to pick up their speed.

The rest of a fartlek treadmill workout should follow the same rules as above, including maintaining an easy pace immediately following a higher intensity interval and then returning to your normal pace up until the next burst of speed.