I’ve done a couple of posts about mental health and running but today I thought I’d have a look at something more physical. It’s just as important and I’m also conscious that the mental health stuff may seem a little awkward to read. Importantly it’s easier to interpret something which you can relate to. So whilst going for a 1am run may make absolute sense to me, it may make less sense to you.
I thought I’d look at fuel. Let’s start with a picture:
Fuel: it comes in different ways
There is plenty of literature which explains how the body breaks down food in order to produce the energy it requires to work. I’m not going to go into that aspect in much detail here.
For running, we tend to think of our fueling in broadly two camps:
slow burning stores
quickly available stores
If you do any reading about training for a marathon, you’ll no doubt see both aspects covered. The comments below focus on the energy ‘system’ you predominantly use when you’re running for more than a few minutes, known as the ‘aerobic energy system’ because oxygen is used to help create the fuel.
The slow burning store
You’ll have heard of carbohydrates before. Broadly speaking they’re made up of sugars and starches which the body converts into glucose. This is stored in the body as glycogen and is one of our main fuel supplies when we’re running.
The glycogen stores are finite. Imagine them as a virtual coal shed. There’s only so much you can store in the shed. Marathon runners will often talk about ‘carb loading’ the night before a race. What they’re trying to do is to fill those stores to their maximum. But that’s the point, it’s limited.
You may have heard of people ‘hitting the wall’ in marathons. That’s not (usually) a reference to a collision with street furniture. Instead it’s when the body has emptied it’s coal shed of fuel. Well you know what happens if your car runs out of fuel, it can’t power itself to keep going. When your glycogen store is depleted, running becomes beyond difficult.
You see those limited stores only hold enough fuel generally for about a couple of hours of running. Without a top-up of fuel, you’ll hit the wall hard.
The fast burning store
Time to introduce another term you may already be aware of. ‘Glycemic Index (GI)’.
All carbohydrates have a relative GI figure which indicates how quickly each food affects your blood sugar (glucose) level when that food is eaten on its own. GI is an important measure for those with diabetes as food which cause a sudden spike in glucose can cause a lot of grief do to the person’s inability to produce insulin.
However, if you’re out running and low on fuel, you need to consume something which will get that fuel into your system ASAP. So we’re looking at high GI carbs for this job.
And whilst that sounds like something very complex, it’s not. Basically you’re eating sugar which goes to work almost immediately. Of course it wouldn’t be practical for everyone to run around with a bag of white stuff from ‘Tate & Lyle’. So there is an entire industry providing easy to consume foods for sports-people.
I’m talking it this way around because it doesn’t really matter what that GI food is you eat, they all do roughly the same thing. However, you ideally want something convenient to carry and use.
These things most people will recognise to be gels. But they come in all sorts of different forms and flavours and you need to remember there’s nothing ‘magic’ about them. They’re just a convenient package to get that quick-fire energy into you.
It’s very individual
Most people would need 30-60g of carbs per hour of exercise, although this varies by individual and by the intensity of the exercise. Again this is where gels are useful as they’re a measured amount of carbs. But equally you could take a bag of jelly babies and, knowing the weight of an individual jelly baby, you could take the requisite number of sweets at a time. One advantage of this approach would be to space out that intake over time so there’s a constant flow of incoming carbs. Although you may drive yourself mad eating a jelly baby every 2 minutes during a marathon…..
Not all gels/products are the same though as the manufacturers will add different things in to aid performance. The reality of this is that they’re not all equal, nor do they work the same for each individual. So Gel A may work for me, but have no positive benefits to you. Gel B may be your wonder food but would send me urgently looking for a portaloo.
The take-home point here is to try out different products in your training so you know what works for you. Don’t rely on what is provided at the event unless you’ve ascertained it works for you. But to be honest I always take my own. When I ran Wrexham marathon last March, the advertised sports drinks and gels didn’t make an appearance on the day. So had I been relying on that, I’d have been stuffed.
Hydration and salt
It is just as important (if not more) to ensure you keep your fluids up during a race. Generally when we’re warm we sweat, losing both water and salt. Both are extremely important to keep the body working; without them that huge store of carbs in your ‘coal shed’ cannot be transported around your body to provide the energy to your muscles.
There are many energy drinks on the market. Those listed as ‘isotonic’ supposedly include a variety of natural salts to help replenish those lost through exercise. But if you’re just taking water on board, you may need to get some salt into you, especially in harder/longer races. Salt/Isotonic tablets are available.
As for the gels, try out your energy drink choices in training. If drink A makes you want to projectile vomit immediately upon tasting it, you don’t want to be finding that out for the first time 6 miles into a marathon!
It was a bit chilly today and also a lot busier than yesterday’s outing. Given it’s Friday and getting anywhere in Stockport is a nightmare all day, I ran around a local park instead. And I enjoyed it. Here’s the data:
In case you’ve only just joined, #REDBED is my December 2017 Challenge to Run Every Day & Blog Every Day. Here‘s the original post explaining what it is I’m doing and why.