How tired should I be after a run?

How tired should I be after a run? I am not the most consistent runner and have always read about not "overdoing" it in order to stay motivated. Of course, this is a nice idea but I'm not great at pacing (I need to get a tracking device, I guess) and I want my running to get me stronger and fitter; I don't just want to jog. So what should I be feeling the day after? Anon

A This is a very interesting question, and one I really need to answer for myself too, so thank you for feeling uncomfortable enough to write to me about running too far within your comfort zone.

I hadn’t heard about “not overdoing it” in order to stay motivated and I find the opposite applies – I feel most motivated when I have overdone it, when I’ve pushed myself well outside of my comfort zone.

This happened recently during a 10km race and in training for it, when I ran further than my usual three to four miles. The feeling afterwards – both in training and in racing – was of greater satisfaction and a wonderful sense of achievement. No doubt I was also tired but I don’t remember it. The tiredness was only in the sense that I slept like a log and was well aware my legs had been for a run when I got out of bed, whereas I don’t notice my legs at all the day after my regular runs.

Since that race though, I’ve gone right back to the old comfort-zone runs, never feeling tired and not getting nearly as much out of my runs as a result.

I know from experience that to improve my strength and fitness through running that I have to mix things up: change pace, take on a hill and/or increase distance. What I hadn’t focused on, before your letter, was how tired or not I have felt afterwards, so over the past seven days I’ve run like I was training for a 10km and thought specifically about my tiredness, both overall fatigue and leg ache because there was surprisingly little I could find online on this topic.

Everything I found was about how to avoid intense fatigue from “too far, too fast too soon”. Our mantra could be “too short, too slow, too infrequent”.

I didn’t overcomplicate things by changing my route, nor did I use a pacing device as I really don’t like them (but don’t let that put you off). I simply increased the length of my run on the first day, being careful not to increase my speed and mindful of the “breath test” – that it is important to still be able to hold a conversation.

This may well mean slowing down from the pace of your usual run – it did for me – in order to increase the distance by, say, 10 per cent as I did. A longer run is the key to improving your endurance.

Technique tweaks can also improve your speed, which in turn will improve your fitness. Running coach Nick Anderson recommends to "think ski jumper" by running tall and imagining a thread pulling the top of your head upwards, plus running with a slight forward lean from your whole body, not just the hips.

And to get your feet to land underneath your body, not ahead of it, mid-foot striking the ground rather than a heel strike to help optimise efficiency. This will no doubt be distracting while you try it out, but technique tweaks once mastered can have a real impact on your running fitness over time.

On my second run the next day, I did my usual run but introduced random sprints, not to a particular pattern, just four or five times during the run, sprinting for, say, 100 metres. To do this I just counted to 100 in my head.

Another useful tip is to do your usual run with parts of it at “tempo” (threshold) pace which is just slightly outside your comfort zone. I did this the following day during another usual comfort zone run. I ran at tempo pace for three sets of roughly five minutes over my usual 30-minute run. I then had a rest day and repeated the same three runs over the next three days. I’m completely shattered.

But after each run I was much closer to that elusive runner’s “high” and the rest of my day was super productive with a deep sleep at the end of it, so the tiredness felt well worth it.

The following day I felt it in my legs, but it was nothing I couldn’t handle and the deep sleep made me feel so well rested that I felt the opposite of fatigued. I felt pumped.

So, I don’t know exactly how tired you should be feeling after running, but if you want to get fitter and stronger, you are going to need to mix things up – run longer, run faster, use sprints, use hills if you have access to them. It’s only when you really stretch yourself that your strength and fitness will improve. And when you do stretch yourself, you will feel tired.

In fact, a valuable measure of how much you have stretched yourself – and are therefore improving your strength and fitness – is how tired your legs feel the next day. If you are worried about overdoing it, take a rest day. And then run yourself tired again the following day. Try it out. You are going to love it. For what it’s worth, it’s how I’m going to be running from now on.

Ruth Field is author of Run Fat B!tch Run, Get Your Sh!t Together and Cut the Crap.