Breaking in running shoes: how long it takes, and when it won’t help
How many runs before a race, why a blister is a fit warning rather than part of the break-in, and the race-day rule.
Published Oct 28, 2026
A new pair means fresh-foam smell, spotless uppers, and the temptation to debut them at Sunday’s race. Bad idea? Yes, but maybe not for the reasons you think.
The short answer
Modern running shoes need far less breaking in than leather dress shoes, and brands don’t even agree on how long it takes:
- ASICS says two to four weeks for a pair to be broken in.
- Brooks suggests starting with 20 to 30-minute runs and building up over a week or two, noting that some newer models feel comfortable from the first run.
So what matters isn’t a number of miles but a check: does this shoe work for you, over distance and at your pace?
Blisters: a warning, not a break-in
This is the key point. A new shoe can feel a bit firm or stiff for the first few days. But Brooks is clear: blisters, pain or discomfort are signs that you may not be in the best shoe or the right size. ASICS agrees: if your toes press against the front of the shoe, that’s a sizing problem, not a break-in problem.
Depending on where it rubs:
- Blister on the back of the heel: your heel is moving. Try the heel lock, explained in our guide on running shoe lacing techniques.
- Toes hitting the front: the shoe is too short. Recheck your size with our running shoe size chart; brands don’t all fit the same.
- Rubbing on the side of the forefoot: the shoe is too narrow for you. Looser lacing at the front can help; otherwise, look for a wide version.
Breaking them in, in four steps
- Indoors first. An hour or two walking around in your running socks. You’ll find a pressure point without getting them dirty, which matters if you want to send them back: check the retailer’s return terms before you head outside.
- Short, easy runs. 20 to 30 minutes at easy pace, as Brooks suggests.
- Build up. A long run, then a session at your race pace.
- Sign them off before race day. At least one run at race pace before the race: that’s when rubbing shows up that you’d never notice on an easy jog.
And socks: synthetic or wool blends rather than cotton, which holds moisture. They matter as much as the shoe when it comes to blisters.
New version of the same model: what needs breaking in?
If you’re buying the next edition of your favourite pair, the break-in is often minimal, but not always: a new generation can change the foam, the stack height or the shape. Before you buy, see what actually changed, number by number: Novablast 6 vs Novablast 5, Ghost 18 vs Ghost 17, Gel-Nimbus 28 vs Gel-Nimbus 27.
Race day
The marathoners’ rule fits in one line: nothing new on race day. ASICS and Brooks both advise against racing in a pair you’ve never worn. If you bought racing shoes, save them for the race, but do at least one or two sessions in them first.
Sources
- ASICS, “How to break in running shoes”.
- Brooks, “How to break in running shoes”.
Questions and answers
How long does it take to break in running shoes?
Brands disagree: ASICS says two to four weeks, while Brooks suggests a few 20 to 30-minute runs over a week or two and notes that some newer models feel comfortable from the first run.
Is it normal to get blisters from new running shoes?
Not really. Brooks says blisters, pain or any discomfort are signs you may not be in the right shoe or size. A shoe that feels a little firm at first is fine; a blister is a warning, not a rite of passage.
Can I run a marathon in brand-new shoes?
ASICS and Brooks both advise against it. Do at least a few runs in them, including one at race pace, to check that no hot spot shows up over the distance.
Can you break in running shoes by walking?
Walking around the house is a good first step: you spot a pressure point without dirtying the shoes. Then move on to short, easy runs, because some rubbing only shows up at running pace.
