Pretty much every runner’s GPS system comes with its own heart rate monitor. Cool! But while many of us may glance at our watches and marvel at the number shown, what does it really mean?
I’m an ultra runner and I’ll admit to not really paying much attention to my heart rate before making the step up to marathon. Fast forward and now, I’m a bit of a heart rate zone geek. Why? Because my heart rate gives me an immediate insight into what my body is up to and how it’s feeling which is kind of important when I’m on the trail for five or six hours at a time.
According to the experts no matter how skinny we may be we all have enough fuel in our bodies to supply our energy needs for quite some time – days in fact! Where it all goes wrong and we ‘hit the wall’ is when we run out of glycogen. That’s the stuff our muscles store up for immediate, rapid energy use. We all have about 90 minutes worth of this type of fuel supply, no matter how much pre-race carb loading we do. I guess that maybe a lion can be outrun in an hour and thirty minutes and so our hunter gatherer ancestors didn’t really need a bigger supply of adrenaline triggered power!?
The long term, long distance, supply of endurance energy is fat. However, we need to train our bodies to tap into our fat stores as an energy supply and that’s where heart rate training comes in. It would appear that we can only utilise this supply while in the lower heart rate zones – that’s the aerobic training zones since we need a good supply of oxygen to burn said fat.
Back in the 1970s, Dr Phil Maffetone, the guru of heart rate training, first started measuring heart rates as a training tool and by the 1980s he’d developed a formula that anyone could use. The 180 Formula became the gold-standard for calculating your max aerobic heart rate training zone without the need for fancy kit (note: this is not your maximum heart rate but the highest value at which you can utilise fat as an energy fuel). There are loads of other articles online explaining what this means and how to calculate the 180 Formula so I’m not going to bore you with it now – suffice to say that is works. I do make a slight adjustment on the formula but basically stick to it.
“So why isn’t everyone doing it?” I hear you cry. Well the downside is that heart rate training can be pretty darn lonely. Your aerobic training zone is based on you, your heart rate, your current fitness level and not anyone else’s. This means the pace you can sustain in your aerobic zone probably doesn’t match up with your running buddies, hence you’re on your own.
Initially, the pace you can hold in your aerobic zone is slow, very slow. It’s like you have to convince your body that you’re not going to cane it and push it into its anaerobic training zone every time out, like you were doing previously. These first few weeks will involve lots of walking, resting, sighing and doubt.
“How can I be getting a training effect?” you’ll question. “I’m not working hard enough,” you’ll say as you walk again. Remember, heart rate will increase with exertion (increased speed and hills), heat, humidity, stress, eating, illness, hormones, lack of sleep, driving, noisy kids… anything you’ll discover can annoyingly push your heart rate up out of its aerobic zone.
I’ve found that it takes 10 to 12 weeks to persuade your body that fat-burning is the way forwards. This period of endurance base training is the frustrating bit and not many athletes can stick it out. Every run is a test of will power and is best measured in time rather than mileage… and this is also when you need to start to build up to several hours on your legs. Strength goes hand in hand with endurance.
The frustration kicks in as every run follows a similar cycle. You start out running and at about a mile in your heart rate shoots up, you walk, it comes down, you run again, it shoots up, you walk (all your running group have left you by now), you try again… and so it continues. Gradually, however, the distance at which you have to walk, gradually, very gradually increases and then as if by magic, if you haven’t cheated and slipped in any anaerobic sessions you’ll be trotting along minding your own business in your aerobic training zone. And the feeling will be amazing, all of a sudden your legs will let you go further, your recovery will be quicker since your body isn’t depleted of its muscle-based energy reserves nor will it be trying to rid itself of the toxins associated with glycogen burn, and before you know it you’ll be running easier and faster than you ever could before (of course there are a few more tricks of the trade 🙂 )
Patience is the key to aerobic training and that’s what we, as runners, aren’t very good at. We want overnight results. We want to be able to run faster without having to endure the long slog, we want to be able to race every few weeks without having first built a strong endurance base. Aerobic training involves planning your A-races, and very few at that. Once you’re through your endurance base training period, you can add in the anaerobic training stuff.
I typically spend the desert summers heart rate base training. This serves as productive training during an otherwise naff time of year and protects me to a certain extent from the heat and humidity of a crazy time of year. My heart rate will tell me things are going seriously wrong before the nasty effects of the sun really kick in.
If you’re lucky, you’ll have had your VO2 max calculated before you start your endurance base training. From this, your most accurate aerobic and anaerobic training zones can be calculated. Here in Qatar, us Joe Bloggs runners don’t get that opportunity so we have to undertake some more number crunching, run pace testing and guesstimating before we can properly power-down. But, as a result of your aerobic base, you should find that you have to get pretty fleet of foot to run when you’re reading to go into your anaerobic zones.