06/10/2026
How little can you run without losing fitness? Less than you think.
There are two things that stop runners running: an injury, or a diary that's too full. Both come with the same worry, that the fitness you worked for is draining away. It isn't, or at least nowhere near as fast as you think.
Building fitness takes a big training load. Keeping it takes far less. A review of the research found endurance can be maintained for up to 15 weeks on as little as two sessions a week, as long as the effort level stays the same.
And if you stop completely? Well-trained endurance athletes lost about 7% of their aerobic fitness in the first three weeks off. After 12 weeks, it was still higher than in people who had never trained.
Here's what to do:
Tip 1: Cut the easy miles, keep the hard ones
Intensity is the part your body can't do without. If something has to go, drop the easy runs first and protect your tempo runs, intervals and hills.
Tip 2: Two short, hard runs a week
Run twice a week for 25 to 30 minutes, with 10 to 15 minutes of each at a properly hard effort. If you can fit in one longer run, keep it.
Tip 3: Can't run? Match it on the bike or in the pool
Your heart and lungs respond to effort, whatever produces it. Replace each run with the same time at the same effort. Only use an option that's pain-free, and check with your physio first.
Tip 4: Keep one strength session
20 to 30 minutes, once or twice a week: squats, split squats, step-ups and calf raises. If you're injured, do only what's pain-free.
Time off doesn't put you back to zero. Protect two hard efforts a week and you'll come back close to where you left off.
Save this for your next busy week, and send it to a runner who needs to hear it.
