What Is Fartlek? Unstructured Speed Play for Runners
Fartlek is a training method that involves continuous running with varied paces, alternating between fast segments and slower recovery periods. Unlike structured intervals, these changes in speed are unplanned and playful.
At a glance
- Term
- Fartlek
- What it is
- Unstructured running workout
- Section
- Fitness and training
- Also called
- Speed play
- In one line
- It’s a fun, unstructured run where you mix in random bursts of speed, like sprinting to the next lamppost and then jogging to recover.
What Fartlek means
Fartlek, which means ‘speed play’ in Swedish, is a form of continuous running that mixes different paces and intensities. Instead of sticking to a rigid structure of timed intervals on a track, a fartlek run is spontaneous and creative. You might decide to run fast to a specific tree, jog up a hill, and then walk for a minute to recover. The duration and speed of these efforts are determined by how you feel, making it a flexible and intuitive way to build fitness.
This type of training is an excellent way to introduce speed work into your routine without the pressure of a stopwatch. By alternating between faster and slower running, you challenge both your aerobic and anaerobic systems, improving your overall cardiovascular fitness and running speed. Because it’s based on feel, fartlek also teaches you to listen to your body and understand your own effort levels, a valuable skill for pacing yourself on race day or any other run.
The main appeal of fartlek is its freedom. It breaks up the monotony of steady-state running and can feel more like a game than a workout. This playful approach can make running more enjoyable and sustainable. It’s also highly adaptable to any environment. You can do a fartlek run on trails, city streets, or in a park, using natural landmarks like hills, benches, or streetlights as your targets for changes in pace.
While fartlek is great for general fitness and keeping runs interesting, it has its limits. Because it’s unstructured, it’s not as precise as traditional interval training for targeting a specific race pace. It also requires self-discipline to push yourself during the faster segments and to ease off enough during recovery. It’s a workout that relies more on your internal sense of effort than on external data from a watch or heart rate monitor.
What public guidance says
A fartlek run can contribute to the weekly aerobic activity recommended by physical activity guidelines. Depending on the intensity of your efforts, it can count as either moderate or vigorous exercise.
How to Do a Fartlek Run
- Start with a warm-up of 5 to 10 minutes of light jogging to get your muscles ready.
- Pick a landmark in the distance, like a stop sign or a big tree, and increase your speed until you reach it. This pace should be challenging but controlled.
- After reaching your target, slow down to a comfortable jog or a brisk walk for your recovery period. Catch your breath before starting the next interval.
- Once you feel recovered, pick a new landmark and a new pace. You can vary the length and intensity of your fast segments throughout the run.
- Continue this pattern of ‘speed play’ for the main portion of your workout, typically 15 to 25 minutes.
- Finish your run with a 5 to 10 minute cool-down of easy jogging or walking, followed by light stretching.
Fartlek vs. similar terms
| Compared with | How Fartlek differs | What the other term means |
|---|---|---|
| HIIT | Fartlek is a continuous, unstructured run where pace changes are based on feel or landmarks. | HIIT involves very specific, timed intervals of near-maximum effort followed by complete rest or very low-intensity recovery. |
| Tempo Run | Fartlek involves many changes in pace, from slow jogs to fast sprints. | A tempo run is a sustained workout at a single, challenging but manageable pace for a set duration or distance. |
Common misconceptions
- Myth: Fartlek is only for elite runners. Fartlek is adaptable for all fitness levels. A beginner can alternate between walking and jogging, while an advanced runner can incorporate intense sprints and longer fast sections.
- Myth: You need a GPS watch to do a fartlek run. The spirit of fartlek is to run by feel, not by data. It encourages you to be spontaneous and use your surroundings as a guide, making it a great way to run without technology.
- Myth: Fartlek is the same as just running around randomly. While it is unstructured, fartlek is a purposeful workout. It intentionally includes periods of faster running to improve speed and endurance, unlike a simple recovery jog.
Related terms
When to bring in a professional
While fartlek is a safe and adaptable workout for many, it’s a good idea to consult a professional if you have specific health concerns or goals.
- Talk to a doctor or physical therapist before starting a new running program, especially if you have a chronic health condition or are new to exercise.
- See a physical therapist if you experience sharp, persistent, or worsening pain during or after a run.
- Consider working with a certified running coach if you want to integrate fartlek training into a structured plan for a specific race goal.
How this entry was made: drafted with AI assistance from general, widely published definitions, checked in a separate verification pass for invented numbers and claims, and edited by the Millennials Wellness editors. General information only, not medical, financial or legal advice. Last checked October 2026. Our ground rules · Back to the glossary