Undesirable, Slowed Pace After Running a Half Marathon

by Andrea
(Richmond, VA, USA)

Lately, I seem to get tired more quickly when I run; my pace is a lot slower, and sometimes I cannot finish my planned mileage without walking or taking a break.

A little background:

For the past year I have been running off and on. I started out doing a 10k about ten months ago. I joined a training team for it, running 3-5 miles 3-4 times a week and longer on the weekends according to the training schedule. I ran the 10k in 1:00:15. I ran sporadically after that for a couple of months. Then I took some time off from running for three months and got back into running when I decided to do a half marathon.

I joined an intermediate training team that went for three months right uptil the race, which was two months ago. I ran 5 days a week ranging from 3-5 miles during the week and then the gradual increase of miles with my training team on the weekends.

For example: one Saturday we would run 8, then the next 9, and then a fall back to 7 the weekend after. This increased as we got further into the program. I started out running about a 10 minute mile and over the course of training I knocked it down to about a 9 minute mile. The day of the race I ran an 8:30 mile with a time of 1:51:25.

About a week or two after the race, I signed up for another half marathon which will be in about two months time. I didn’t really take any time off, maybe a week, and started at the beginning of the training schedule I followed for my previous half marathon.

I have found over the past month and a half, my pace has been getting a lot slower, to somewhere between 10 and 11 minute miles. I struggle to do the longer distances, and my legs just feel exhausted running in general while I don't really feel winded.

I have had to deviate from the training schedule and run only about 3-4 miles, 3-4 times a week with the longer runs on Saturdays still. I have talked to others that I run with, and they told me I didn’t rest enough between my training.

The problem is that I am only 2 months away from my next half marathon and I don’t know how I should continue. I want to beat my previous half marathon time, but with how things have been going, I don’t think that is a possibility.

What should I do about my training?


Answer by Dom:
Hi there,
Thanks for your question about your half marathon training struggles. And thanks for providing the background information.

It's tough to work out exactly what is wrong. At any given point in time we may be dealing with different things that can cause decreased performance. Changes in working circumstances, diet, sleeping, etc. There may be multiple reasons why you are experiencing this.

Yes, I think your training partners could be right here; you may not have rested enough.

What I wonder about is how tough the half marathon training was for you. Did you get to run many runs at a slow/easy pace or were most of the runs pretty tough? How high did your heart rate get on these runs?

There are many benefits to group training; the additional push to do your scheduled runs, friendships, advice, etc.

The disadvantage can be that the group pushes you to a pace that is too fast for you. Short term this provides some good results as you have experienced; you'll get fit quickly.

But when you run at a pace that is too tough for you and don't rest sufficiently in between you do run a risk of "breaking down".

Additionally, it is very normal to run much slower in training, than during races. It appears that you really want to hang on to that race day performance. It is actually healthy to do most of your training at a slower pace.

Most people would probably tell you to stop running and exercise completely. I wouldn't do that if I were you. But I would make some changes to your running training approach.

Start doing really easy running for a while. With that I mean running at a slow pace at which your heart rate will be pretty low. There are different formulas to do this and I'll provide you with a few calculators:

Zoladz heart rate monitor calculator

Karvonen heart rate monitor calculator

For these calculators, work out your Zone 1 heart rate zone and stick to that until you start feeling markedly better while running.

As an alternative, you could use the Maffetone base training max heart rate formula of 180 - age.

I am guessing that all formulas will lead to roughly the same outcomes, there is always a bit of difference, so don't get caught up in the detail. But they will all ask from you to keep the intensity of your runs down to a minimum.

At this training pace you should not experience, as much, the heavy legs and the fatigue. You'll hopefully find this pace to be very relaxing and not tiring at all. Although in the beginning it may be a bit frustrating as you might be required to walk during the workout to keep your heart rate down.

And your pace may decrease to 11, 12, 13 minute miles. Whatever it is, just focus on keeping your heart rate down and enjoying the experience.

Over time this will improve your aerobic base and it will help set you up for long-term running success. Also see my base running page for more info.

With regards to the half marathon scheduled two months down the track: see how you feel closer to the date. At this point in time I wouldn't focus on it or do any dedicated training for it.

You could still run it for fun and for the experience. But it is best to focus on low heart rate training and start feeling better first, then schedule in your next half marathon attempt.

The good thing is that it is such a popular distance that there are plenty of half marathons to choose from at any time of the year!

Hope this helps.
Best of luck.
Kind regards,
Dom