One of the most difficult lessons you’ll learn at running school is that in order to train hard, you don’t always need to run hard. In fact, tearing yourself a new one every time you go for a run can be counter-productive and leave you broken and disillusioned and sitting in the matron's office with a cup of strong sweet tea.
In my Training Toolkit article I explained how different runs help your body to adapt to faster running, and suggested that your training should include a healthy combination of these runs. But if part of the fun you get out of running is in challenging yourself, then it’s easy to struggle with motivation on slower runs, and tempting to push yourself every time you run. And that’s why I love heart rate training. Read on!
It starts with a nice lie down, ideally before you’ve even gotten out of bed. See just how low you can get your Resting Heart Rate (RHR) – it shows how much work your heart has to do just keeping your body functioning. An elevated resting heart rate can sometimes be the first sign that you’re getting a cold, or that you got wasted the previous night.
This next bit isn’t so much fun. Do a 5k as hard as you can, or run up and down a hill fast until you’re ready to puke. This helps find your Maximum Heart Rate (MHR), and thankfully you won’t have to spend much of your time here. You may have seen various ways to estimate this figure by subtracting 75% of your age in dog years from your mother’s maiden name, but there’s no substitute for the accuracy of testing it yourself.
Over time, you might find that your RHR falls as you become fitter – and you might find that you’ll exceed your MHR by a few beats during a particularly tough race. That’s cool, just check them every so often, and adjust the figures appropriately. It's not uncommon to occasionally see excessively high numbers - usually as 'spikes' when you look at your heart rate for an entire run - but this is often down to a variety of spurious reasons, including faulty chest straps, bad connections (not enough spit on the contacts), or an overhead powerline / passing meteor.
Heart rate is an excellent measure of how hard your body is working. Your pace might drop dramatically when running up a sand dune or gravelly hillside, but your ticker gives a truer picture of what your body is going through. The range between RHR (let’s call that 0%) and MHR (let’s call that 100%) has some important gear changes along the way. Enter your values to see your target figures:
Recovery Aerobic Anaerobic OMG! 60-70% 70-80% 80-90% 90-100% Improves endurance and aerobic capacity, burning fat as a fuel without using too much glycogen. In this range you begin to develop your cardiovascular system. Here’s where to pitch a tempo run to help your muscles handle lactic acid. This is where you should aim for during interval training to improve muscle fibres. Up to 148bpm 148-162bpm 162-176bpm 176-190bpm
At low intensity, you fuel your muscles using fat and lots of oxygen – and training at this level helps your body adapt, improving the ability to deliver oxygen to your muscles and making this process more efficient. Many runners would benefit enormously from building a solid base of training at low intensity, to get their aerobic systems tuned up.
At high intensity, your muscles are working much harder, using a greater proportion of glycogen as a fuel, and your body has to deal with all sorts of chemical by-products, including the production of lactic acid. Pushing your training into these upper zones with tempo runs and interval training will help your body adapt to handle this too.
Fall between these two intensities, and you miss out on the training effect that they offer. Run in the middle and you’ll burn off your glycogen rather than tuning up your oxygen and fat burning systems. Train in the grey area between hard and easy and you won’t make your muscles work hard enough to teach them how to handle lactic acid. Training well is about understanding the importance of both processes, and devoting the right amount of time to each.
Earlier I hinted at how heart rate training can help during slower runs. Set your watch up to scream like a pound shop burglar alarm every time it goes over (say) 150bpm, force yourself to slow down until it stops beeping, and challenge yourself to see how fast you can run without setting it off. You’ll find yourself concentrating on your breathing, trying to run relaxed, and even completely forgetting about mileage, which I always find is a good place to be.
Of course, we’d all like to see our times improve when we are trying our hardest. But if you can improve your performance at low heart rates, and train your body to make better use of its fat-burning and oxygen-delivering capabilities, not only will that help your endurance, it follows that you’ll see an improvement in your race pace when your heart is working harder.
There’s no absolute need to wear a heart rate monitor to use this approach. It’s all about disciplining yourself to run at different levels of intensity, and you might find that you can do this by feel. But heart rate feedback will certainly help you to see just how hard you’re working when you run – and can definitely add an extra dimension of challenge to those slower runs.