How many miles per week should I run for a marathon?

Never make large jumps to the miles you run per week. If you’re starting point is 15 miles on average, I’d not recommend immediately increasing this to 20+ miles. I also don’t personally prescribe to the 10% increase that’s commonly used, or 3 weeks increase with a reduction on week 4. There are too many things that can go awry in training for these kind of plans in my view, with miles missed.

Whether you’re raving for a specific time target or for completion will also have an impact on how many miles you need to clock up each week. Highly competitive amateurs (by which I mean those in the Championship start) will be running 60-70 miles most weeks in training for the London Marathon with times of around 2hrs 30 to 2hrs 45. If you’re looking to complete the distance nearer to 6 or 7 hours, you don’t need to push your training in the same way.

If you’re someone who’s injury prone you might want to run higher mileage with lower intensity rather than fast, shorter sessions which may pose a higher risk or strained muscles. If muscle injuries aren’t your problem but your joints can’t take the impact as well, then harder sessions may actually suit you, this can be a very personal choice.

Highly intense sessions need more recovery time for the muscles and nervous system so if you like to do predominantly these types of runs, you’ll need to drop the miles you run overall. Happy with slower running? Then you can add in some extra miles without too much worry.

If you’re eating well with high quality proteins and plenty of carbohydrate, plus taking good quality active recovery (via stretching, foam rolling, massage, swimming etc) then you can also allow yourself some extra training miles. The less you do to recover, the fewer miles you can probably manage in training without injury or detriment to race day.