From: Robin Stead
Sent: 15 March 2010 20:16
To: 'Wayne Soutter'
Subject: FW: The BEEEG Swim!
Hey Wayne,
You really are an awesome human being!
OK, here's the absolutely definitive story on endurance and energy!!
1.Glycogen.
When we eat, our body decides where and how to store its
energy. If you're in couch potato mode, most of the surplus carbohydrate and fat (especially fat) gets laid down as adipose tissue. It's available if it should be needed in the future, but it's fairly inefficient in releasing energy. If you're active (and your diet favours carbohydrate instead of fats), the body lays down glycogen. This happens in the liver and in the muscles. Glycogen is readily available as a source of energy, and is what keeps endurance athletes going. The actual amount of glycogen available is generally regarded as less than you would expect to provide sufficient energy for the long haul, so there seems to be agreement that the stores need to be replenished during the race.
2. Insulin.
When we eat carbohydrate, it is digested in the gut and
glucose molecules find their way into the bloodstream. Glucose in the blood triggers release of Insulin from the pancreas. Insulin draws the glucose out of the bloodstream and puts it away as glycogen (which consists of a long chain of glucose molecules).
3. Adrenalin
Adrenalin is released during stress, and changes the blood
circulation to favour the periphery over the core (the "flight and fight"
mechanism). The combined effect of glucose and adrenalin is a very rapid removal of glucose from the blood, and a poor digestive capacity. If you take in glucose while endurance racing, you get a switchback effect - short period of feeling great followed quickly be low blood glucose again. Most of the glucose actually goes out in the urine in those conditions.
4. Maltodextrin
An alternative to taking glucose is Maltodextrin, which consists of
a chain of glucose molecules. When you consume it, it drip-feeds into the system, bringing it into the blood 'below the radar' so it doesn't cause the insulin spike that glucose does. Maltodextrin may be found in many energy drinks, though the quantity is generally quite low. The next option is too buy Corn Syrup, which is a thick, gelatinous sachet. Other sachet-type preparations also contain it, but usually the concentration is lower than Corn Syrup.
Maltodextrin can be bought as a powder, usually from Health
Pharmacies. It's bizarre - it's bought by the ton from the Chinese, but everybody protects their market, so it's difficult to buy in small quantities. If you can get it, it's cheap to buy, and I'd get 20kg or more if I were you. I use it every day, because at my advanced age, blood glucose tends to drop 2h after a meal - that's why old folks typically nod off every now and again! I add it to tea or water (it's virtually tasteless) and it stabilizes the blood glucose perfectly. I don't know how much liquid you would take in on a swim, but you may need to experiment with the ideal concentration to use. It dissolves slowly in cold water, but if you leave it for 10 min or so, the solution becomes clear. If you want to bump up to higher concentrations, you can warm up the water to speed up dissolution.
The symptoms of hypoglycaemia (low bs) in endurance racing are:
disorientation, lack of energy, confusion etc. It's the "wall" that athletes often refer to. While racing, it's important to pre-empt the symptoms, so you take in maltodextrin on a regular basis (you'll probably have to experiment with your conditions to get the timing right).
Also, the best way to lay down glycogen in the muscle during training is through putting in the time swimming. Bursts of speed don't help - steady swimming does. Carboloading only works if your muscles are prepared for it.
I hope that helps a bit, and do let me know if can add anything to this epistle!
And GOOD LUCK with this awesome endeavour! Keep me posted on how the training goes.
Warm regards,
Rob
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