So I said in my last blog post that I’d talk about running shoes and also heart rate next time around, and here we are. The reason for raising both is that I really hadn’t realised that they are related – oh yes! Let me explain….

Well firstly I’ve always suffered from a pretty high heart rate, under anything less than resting conditions. Tachycardia I think is the medical name. It doesn’t take even the slightest bit of angst and my heart can pound almost out of control. It gets bad when running too – if I look at any of my previous half marathon attempts, or a hard run of any significant distance (in fact even a Park Run) and my heart can average 180bpm. 

That’s not good really. And especially when the formula of ‘don’t let your heart rate go above ‘210-your age’ would have my max heart rate at 152! I have had alerts before when doing a run to say my heart rate is up at nearly 190, which is actually pretty terrifying. So the very interesting thing when doing a prolonged bout of training for a run like a marathon is the effect on your heart rate, and also shoes matter here too, and here’s what I understand of it, scientifically, as it were:

So basically our bodies have a ‘fight or flight’ reaction in many situations – it is what is called the sympathetic nervous system, something I find fascinating. An(y) increase in intensity basically produces an adrenaline surge, which means blood pressure, heart rate and breathing rate all increase.

Over time however, like a period of sustained training (which I am very much in, obviously), your body adapts to it, which decreases the burden on your cardiovascular system. As your muscles, and your heart, get stronger, they do a better job of extracting oxygen from your blood, so your heart itself doesn’t need to pump as fast to drive blood around the system. It’s all about the oxygen in the blood, which is why the key measure of fitness for example is called Vo2 max. This is the maximum amount of oxygen your body can use during exercise, and the higher the measure the fitter you are basically. 

So this all manifests itself in various ways – your heart rate gets lower for the same amount of strain (or length of run at the same pace), and also the spikes get lower too, as your heart doesn’t react so badly to that fight or flight thing. There is a key to the running too though – in that the majority of it needs to be done aerobically, at a slow and easy pace. If you did lots of running but just thrashed yourself every time then you wouldn’t improve, in short. That’s how I understand it anyway – and if anyone realises that I’ve got this all wrong then please let me know!!

And the tie in with shoes is very interesting too. So again as I understand it, the more your shoes have the likes of ‘rebound foam’, or as is the case with some shoes a carbon plate, then the less energy you need to expend for a given pace or intensity. The shoes are basically helping return some of the energy expended as downforce and basically not letting you waste it by letting you have it back. It’s a bit like being on a trampoline. This also means that for a longer distance you get less tired, and your heart has to work less. Now the differences aren’t staggering – maybe about 3 or 4bpm according to the advertising materials for the Nike Vaporfly Next% or the Alphafly, but every little helps as far as I’m concerned.

For me (and I have both of the above pairs) I think I do actually notice the difference, particularly over longer distances. In my only marathon, where I wore the Vaporfly Next%, I did my fastest mile in the last mile for example. Now adrenaline and excitement I am sure played most of the part in that, but the fact that I had enough left in my legs to do it was the main thing for me. I’ve bought a pair of Alphafly for Berlin – after all if they work for Eliud Kipchoge then who am I to say otherwise? So far I’ve taken them out on just two (slowish) runs, and the jury is still out overall as to how I like them compared to the Vaporfly (they feel a bit heavier and ‘flappier/noisier’ to me so far). I’ll keep going with them on the faster training runs and decide nearer the time whether they get the vote.

And so here we are then at the end of week 12 (of 18). This week was 47 miles, a slight reduction on last week thankfully, but it was still very hard work as it has been brutally hot here – not a phrase normally heard in the Lake District! At the end of week 12 I’ve done just over 400 miles on the programme so far, and it feels every inch of it. I have four weeks of hard training to go, harder than I’ve done yet, and then two weeks of tapering towards Berlin. Having said that, both of the last two weeks are around 50 miles too, albeit at less intensity. One of those weeks includes the Great North Run, which I will be itching to run ‘properly’, but I know I can’t/shouldn’t, as it’ll take too much out of me. I’ll enjoy it nonetheless (and that’s an understatement of all time) – and I’ll talk more about the anticipation of that next time.

Oh and I’m also dreaming a bit of being in the Himalayas in the autumn (in fact I’m just dreaming of not having to run anywhere at all!). Everest Base Camp of course. That needs a lot more thought and planning too, but where there’s a will there’s a way…..

Countdown to Berlin – 42 days. Countdown to the Great North (training) Run – 28 days. Come on!!!!