Reviews and recommendations are unbiased and products are independently selected. Postmedia may earn an affiliate commission from purchases made through links on this page.
If you’ve resolved to get more fit in 2025, you’re in luck, because almost any exercise will steer you toward that goal. But of all your exercise options, few will be as effective, simple, adaptable and enjoyably impertinent to brag about as fartleks.
Fartleks are an informal version of interval training. To start fartlek training, head outside, warm up for a few minutes at whatever activity you most enjoy – whether it’s walking, running, biking, unicycling or snowshoeing – and then pick a landmark a short distance ahead. It could be a tree, a colourful mailbox or an unusual rock formation.
Pick up your pace until you reach it. Then, drop back to your original pace, let your heart rate and breathing slow, and look for another landmark. Vary the distance between these goals, and aim for perhaps 30 minutes of fartleks once a week to start.
Fartleks are one of the most unthreatening ways to sprinkle intensity into our activities, and a growing body of science indicates intensity, even in small amounts, can make workouts more beneficial – not only for our strength and endurance, but our health and longevity, too.
“Fartlek training is quite a good way to improve fitness,” said Ulrik Wisloff, the head of the cardiac exercise research group at the Norwegian University of Science and Technology in Trondheim, who has studied exercise and health for decades. “I do it and I recommend it to people who say they don’t like exercise, because it’s never boring.”
What’s the meaning of ‘fartlek’?
For generations, competitive athletes used highly structured, intense interval training, usually on a track or treadmill, to increase their speed and endurance. This kind of training is potent. It will make you faster. But it’s also grueling, demands expertise and planning and is rarely anyone’s idea of a rollicking good time.
Which is where fartleks come in. Fartlek translates as something like “speed play” in Swedish. The term is usually attributed to the Swedish Olympic decathlete and running coach Gosta Holman, who reputedly developed the concept in the 1930s, after the Swedish cross-country team repeatedly were trounced by their neighbors, the Finns, during international competitions.
The link between intense exercise and longevity
Fartlek training is more than entertaining, though. It’s also one of the easiest ways to amplify the intensity of your favourite exercise, making it even better for you.
So why would you want to make your exercise more intense?
“You’ll see greater increases in VO2 max” with relatively intense exercise, Wisloff said. VO2 max, a measure of our bodies’ ability to deliver oxygen to cells, is strongly associated with longevity, he said. The lower someone’s VO2 max, the likelier they are to die young and vice versa.
The importance of intensity for lifespan was especially evident in a large-scale 2024 study, during which 7,500 middle-aged and older adult men and women wore a high-tech activity tracker for at least a week. Researchers then computed the intensity of their physical activities and followed them for about seven years, tracking deaths.
The overall intensity of people’s daily activities proved to be a better predictor of their longevity than how much they moved around. The most sedentary men and women were about 14% more likely to have died in the intervening years than those who moved around even a little more often. But if people’s physical activities were almost always of low intensity, their risk for death was about 37% higher compared to those whose exercise intensity was even a little greater.
Intense exercise doesn’t have to be hard
Of course, the idea of making your exercise more intense can seem intimidating. But don’t worry, said Martin Gibala, an exercise scientist at McMaster University in Ontario, who studies interval training. Exercise intensity is a spectrum, ranging from light intensity exertions to the kinds of all-out intervals Olympians grunt through.
Simply increasing the intensity of some of your exercise from light strolls to faster walks “can be enough” to boost your health and fitness substantially, Gibala said. The greatest gains come, he said, if you occasionally up the intensity of at least some of your exercise from “green to yellow” on a green-yellow-red gradient of effort.
Or use the talk test, Wisloff said. To find the sweet spot for intensity and health improvement, you should be able to talk during intervals but not sing, because singing demands most of your respiratory resources.
As for me, I fartlek a few times a week to add oomph, diversion and a little glee to my normal workout routine. I like the word. I like the workout. I enjoy feeling a bit fatigued at the end. Fartleks, always varied, never pall.
Just a few days ago, on Christmas Eve, my route happened to be unusually crammed with people on holiday walking their dogs. I made every canine a marker and introduced myself. My intervals may have been brief, but our shared joy was contagious. It was my happiest workout of 2024.