Couch to 5K

I am trying to get back into this running lark. Last weekend I set off early in zero degrees with no wind and with no particular ambition and was very pleased and even more surprised to do an accidental PB of 29:12 for 6k.

Flushed with success I set out today once it had stopped raining to see if I could repeat it. I very quickly learned that running into a fierce headwind (24mph according to my weather app) not only decimates your time but will simply destroy you if you are foolhardy enough to try to maintain a non-windy time. After just 2k I was so far off the pace and so utterly knackered that I decided to give in.

When I got back I decided to research the effects of a headwind and will now share this with you so you don't make the same mistake. I found the following facts at runnersconnect.net/running-... if you want to read the whole article.

- Running into a wind that is equal to your running speed will add about 12 secs per mile / 7.5 secs per km.

- Oxygen consumption / energy usage increases with the square of the airflow over the body. So, the performance hit of a 10mph wind is four times greater than that of a 5mph wind.

To translate this to my own run today, my normal pace is about 5 mins per km or 12 kph. The headwind was about 24mph = 38kph or approx 3x my running speed. To find the total effect of the headwind we must square this 3x (giving 9x) and multiply it by 7.5 secs per km. 9x 7.5secs = 67secs.

I ran my second km today (the one into the wind that nearly killed me) in 5:22. Subtract the 67 secs wind effect gives 4:15. A fast km for me in still conditions would be about 4:20 so all this theory & maths seems to work pretty well and explains why I was so utterly knackered. What I thought was an appallingly poor pace/time was very possibly a PB once the wind effect is stripped out!

Oh, and in case you are wondering; while a tailwind does aid performance, you only “get back” about half of what you put into a headwind when you turn around and run with it at your back. So if I had been going the other way and had that 24mph wind behind me my time should have been about 33 secs better than my usual time for that km.

Well I find it interesting anyway......

Chris L

9 Replies

I did an 'easy' 12k today out on the Somerset levels where it is quite exposed and the outward leg was all into heavy wind. It was incredibly hard going. I was a good 45s/km slower than I would expect and my heart rate was 15-20bpm higher than 'easy' pace. It also felt like I was running on the spot half the time. The return was a mere bagatelle, by contrast.

Ha..I was also out on the Somerset levels today in the Langport / Muchelney area....Yes, it was a bit windy!

Does it matter that you're off the pace if you are trying to get back into this running lark? I know the elite runners might give up on runs that aren't winnable but we're not in that realm are we, so I'd say always hang in there and finish it. Once you're out there, all togged up, it's a shame to call time. If you keep running you can salvage something

Normally I would agree Miss W but the point was that I was physically unable to go on. In my misguided attempt to run at 'normal' pace I had effectively put in an 'all-in' or sprint finish type km. Another 4 km was simply not an option.

I had a really good run last Saturday - longest distance to date. Headed out yesterday hoping to achieve the same but no chance with the strong gusts of wind. I did feel a bit disappointed but I thought the weather must have been a factor. Good to see from your research that I was right!

Great to see you back Mr statistics ....as for your wind, life sucks eh!!!

Hi JJ. Yep, still around, still not completely convinced, still a bit nutty (your label, as I recall).

Interesting stuff! Seems it's been windy everywhere recently too...I'm surprised what effect even the lightest breeze can have, now I know why...

Don't be too downhearted Chris. With this running lark, there is always the chance to do it over again. The wind will die down soon hopefully and we can all get back out there and run our socks off. It's very disappointing when things don't go to plan but it sort of goes with the territory unfortunately. Makes us stronger, more determined runners though doesn't it