*** many thanks to Neil Rooney for this blog post, which is also on his personal blog "Tri and Run Sensible!" ***

If you have endured a long distance race like a marathon, 70.3 Ironman, Ultra Marathon or Ironman in the last decade you'll be fairly familiar with these little packets of sticky gunk. And you will know the difficulty that can arise when trying to swallow this while pushing your body to the limits of cardiac output. So is it worth the hassle?

Gels: Little packets of sticky sugary gunk

Like all these things when you are racing you need to discover by trial and error if they will work for you, if you can swallow them on the move and if you can then keep it down. A lot of these gels will repeat on you for about 20mins after ingestion so it is important to find a brand that taste good but also does what it should. So what should it do?

If we look at these from a physiological point of view they are quite interesting. Energy gels are basically small packets of really easy access glucose, the energy stored in these is so easy to access that you can ingest some of it in your mouth. So about 20seconds after opening the little packet your muscles will be burning it up and the energy will be propelling you forward as you run or it will be turning your bike pedals. This happens because a very unique enzyme (these make things happen) in your saliva called amylase.

All carbohydrates are chains of carbon, hydrogen and oxygen atoms. It doesn't matter if the carbs we are talking about are fizzy sweets or brown rice they are all still the same three atoms, carbon, hydrogen and oxygen but what differs is the strength of the holding chains.

Energy gels and paper chains: easy to break down

The chains of very simple carbohydrates are not very strong. Picture these 3 atoms as being rocks of various sizes and picture the chains of simple carbs (energy gels) as being a paper chain which snaps very easy and therefore releases energy very easily. These carbs are already glucose (which is what we use at a cellular level) and they get burnt instantly (I gave analogies of fuel in previous posts, imagine these as burning like tissue paper) but yield energy for a very short time.

However this is where they can help us with one very interesting aspect of physiology and it's why we really only use them in long endurance races or during training for such events.  In the post "Nutrition 101" I said fats yield most energy but it's difficult to get them burning (because they are like logs of wood) and it requires a small amount of energy to do this. When you are a couple of hours into one of these races or a long training session your glucose stores start running low, you will be well into the fat burning zone and you will be burning lots of fuel. Since you need a small amount of energy to keep the fats burning and the carbs (glucose) is running low, the next easiest fuel to burn is proteins (building blocks) which is never a good idea. So to avoid this you can get the gels out!

Picture this; you set off on a 2hr run. For about 10mins you feel great. Then between 12-15mins you start thinking I'll never be able to keep going for 2hrs. Then when you get about 20mins into it you start feeling good again. You cruise along until about the 1hr10min point where you start feeling a bit tired and perhaps your pace begins to drop a bit. So you pop a gel, and you feel great then 15mins later you start to feel the energy drop so you pop another and this continues on a 15-20min cycle until you finish! And then you can refuel for the next session with some complex carbs and fats.

Keep the fire burning!

Now picture this; you are cold so you crumple up a few newspaper pages and set them on fire, you begin to heat up but after about 12-15mins you begin to worry that your newspaper is going to run out so you need to burn something else before the fire goes out. So you pop a few logs on your fire which take a few minutes to catch fire but 20mins after you started you have a nice fire giving you lots of heat. You keep piling the logs on and about 1hr10mins after you started you realise that you've put too many logs over the cinders, the flames are dwindling and there is a risk your fire will go out. All your newspapers are gone so you take some tissues (energy gels) from the Kleenex box and stuff them under the logs. The flames ignite the logs and the heat returns. 15mins later you pile on more logs but the flames have gone. So you need more tissues (remember the newspapers are gone) until you can go to the shop to buy another newspaper.

So yes these little packets of sheer annoyance have a very important function and they work really well. They will prevent you from burning proteins which means you will recover quicker from a work out. Remember the muscle cells contain the power stations (mitochondria) which allows us to perform faster and longer, breaking these up would be counterproductive.