top of page
  • Writer's pictureAlexa

Why is that first mile so tough?

Runners of all levels talk to me about the fact the first 5-10 minutes of their run always feels a little harder than the rest. For runners starting out it’s often a reason they find the start of their running journey challenging. So, I thought I’d explain a little about why this happens and what you can do to prevent it.

The key point here is that our bodies breathing, heart rate and energy systems work on a bit of a time lag. You might have noticed this if you try to sprint for a train, you can run for 10, 15 or even 20 seconds feeling fine and all of a sudden (usually once I’m on the train) my heart and breathing rate go through the roof and I pant embarrassingly next to another passenger for a while to get my breath back!

Your brain is constantly monitoring the chemicals in your blood and reacting accordingly. It monitors CO2 (carbon dioxide) which our muscles create as they work and is taken via the blood stream to the lungs to be exhaled. Before you start running your body is in a nice rhythm of breathing and heart rate to meet the amount of CO2 you need to expel from your body each minute. Once you start to run your body doesn’t do anything to change the heart and breathing rate straight away… It only knows something needs to change when the CO2 levels in your blood get high enough to trigger an alarm in your brain, which tells your heart and lungs to speed up their work to clear this CO2 backlog. The problem is by this time your body is playing catch up and has to work harder to clear the CO2 in your muscles and blood stream and get the level back down to the desired range.

Heart and breathing rate spike in response to this build up, the backlog clears, heart and breathing rate slows a little (perhaps a bit too much), CO2 levels spike again and the cycle continues until the body works out the right breathing and heart rate for your effort level and settles into that. That’s the point the run becomes more comfortable. Of course when you change your effort level by going up hill, or running faster the body has to find that equilibrium all over again; this process is usually a little faster as you are already breathing at a faster rate than at rest.

Damped sin wave graph showing how heart and breathing rate might settle over time

A similar story plays out with the byproducts of our energy release process in the muscles building up in the blood stream, being noticed by the brain and a sudden effort to clear them out through the kidneys. The process needs time to settle from being reactive to the alarm going off in the brain to finding the right level to work at to keep you running.

So what can you do about it?

The key to improving this is a thorough warm up, you are aiming to gradually awaken and increase your heart rate, breathing rate, and energy production processes at the start of the run. This more gradual start reduces the volume of the alarm bell, the size of that first spike of all the processes kicking in and the time it takes for your body to find the right rhythm to work at.

Start out gently, perhaps with a brisk walk and moving up the gears into a gentle, conversational, run and gradually faster over a 501- minute period. The faster your intended pace for the run you are doing (eg intervals) the longer the warm up should take to gradually build to the effort level you want to train at. You’ll know from track sessions that the warm ups are longer and more thorough for high intensity interval training.

The other thing to consider is your own breathing rate. I know, for example, that when I was running at a gentle, conversational pace, I took three steps for an in breath and 3 steps for an out breathe. Check in with what your breathing rate is compared with your footfall and you can then proactively start breathing at this rate at the start of your run; this can help the body to find it’s equilibrium faster.

331 views0 comments

Recent Posts

See All


Couldn’t Load Comments
It looks like there was a technical problem. Try reconnecting or refreshing the page.

Running Coach

Sports Massage


bottom of page