Lactic acid

[Melody]

Hi Laura. I wanted to clear up a couple of things.

Firstly, our bodies don't produce lactic acid but instead produces lactate, a very important form of energy. The lactic acid production was widely believed to be true for over 60+ years but as we've learned more about how the body works this has been debunked.

What occurs in our body and exertion increases is we begin to rely more heavily upon the lactate created in our bodies. The lactate itself is broken into glucose which is used by the bodies under strenuous activity.

What causes decreased atheletic performance is the production of protons caused by the breakdown of ATP by the muscles during exercise. This production of protons is kept in check until we meet a threshold (normally called lactate threshold) where our oxygen demands outstrip supply. This begins a buildup of these protons in our muscles which increases acidity (acidosis) within them... which is that burning sensation you get from strenuous exercise. Eventually you will have to stop - there is no choice... or at least slow down until your demand for oxygen stops outstripping supply.

When your legs get to the stage of where they feel like they weigh a few ton each this may be caused by two things. It *could* be acidosis. However it's more likely that your glucogen stores have been depleted and that you need glucose.

You could try this experiment. Next time you feel like your legs just have nothing else, stop for 15 minutes then get back on the bike. Track the time to see how long it takes before your legs feel like they have nothing else again.

At a later date try this again but take some form of fuel with you that's high in glucose. I personally use Gu. When your legs give out and you stop, take some of this fuel and wait 15 minutes then get on the bike. Again track the time to see how long it takes before your legs feel like they have nothing else again. I'm betting that you'll have more energy this second time around using the fuel.

Lastly, don't forget those salts! It's one of the things many atheletes don't even think about but it's very important. Your body loses salts as you exercise. In addition to Gu, I also carry bananas with me to eat mid ride.

Mel

PS: When you take in fuel, especially a gel like Gu, it's very very important you also take in water.

PPS: References:
http://en.wikipedia.org/wiki/Lactic_acid
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum
This one is about running but still applies to cycling: http://www.time-to-run.com/theabc/lactic.htm

There are others but I'm having search issues at the moment.