Getting a half marathon time down

Hi everyone, I am planning to run the Wokingham and Fleet half marathons in Feb and March next year.  My 5k and 10k PBs are 22:36 and 46:30 but my best HM time has been 1:49 on the pancake flat Cologne course.  In Feb 2012 I did the Wokingham half without much training and did 1:53.  I would love to bring Wokingham in under 1:50 this year and Fleet under 1:45 (home course, lots of support, know the route well) and think that it should be achievable given my 5k and 10k times.  I'm guessing that all I really need is to get the time on my feet and build up my stamina, as I tend to run no more than 9 miles on a long run and usually closer to 7.  I run 2-3 times a week including one speed session and swim once a week.

Other than doing more long runs, is there anything else I can do to improve my stamina?  I suppose I am aiming to run at 8 minute mile pace for the full 13 miles - last year I averaged 8:05 at the Great South Run and could have done better if I hadn't gone out too fast.  I'll be doing an 8 mile race in January.

I'm a 40 year old female.

You've answered your own question.

You are not running enough weekly mileage to achieve your goals.

You need to build your long run mileage up to 13 and your weekly mileage should be as much as you can achieve without tiring yourself out. The closer to 35 miles a week the better but you may not be able to do this only running 2 or 3 times a week. I would be looking to run 3 or 4X a week.

Your times for the little running that you are doing are quite good, they show that you have potential if you are willing to put the work in.

I wouldn't really worry about speed work at the moment, that's really the icing on the cake. Building your stamina is key here. You need to be able to run the distance with ease.

Sort yourself out with a training plan that you can keep to and fits in with your life. If you have 10 mins to spare then run a mile, if you have to be in then do some exercise that you can do indoors - core for example. If you can get out more then there is no real substitue for running if you want to run.

Agree with T.mouse.

The only other thing I'd say is that you would be better focussing your efforts on one half-mara, so if Fleet is more importnat to you (and its the later one) you need to treat Wokingham as a training run rather than a flat-out race.  Otherwise your recovery from the first one will hinde your preparation for the second one.