At any rate, we have this data from the Tour de France (extracted from a table available here).
|7/2/09||14.3||42.8||0.5||pre-tour, in France|
|7/10/09||14||41.3||0.5||stage 7, 1st mountain day, Contador attacks|
|7/11/09||13.7||40.7||0.5||stage 8, 2nd day in Pyrenees|
|7/13/09||no tests||rest day|
|7/14/09||14.4||43.1||0.7||stage 10, sprinters holiday|
|7/25/09||14.5||43||0.7||stage 20, Mount Ventoux|
In this case the first one of note to rise to the occasion was Jakob Mørkebjerg, a Norwegian blood researcher. I first heard of the story at nyvelocity.com which has good coverage of the story. The one link they seem to leave out is a more recent article at cyclingnews.com. Dr. Mørkebjerg has made three major points about Lance's blood values. First, that his hematacrit and hemoglobin remain very constant throughout the tour, rather than dropping as expected. Second, that his highest hematacrits both occur after rest days, with the implication being that he could hvae added a bit of blood on the rest days, and third that his reticulocyte counts are low, especially in light of his steady hematacrit and hemoglobin.
And before saying that a lack of a drop is a sign of doping, I'd want to know how big of a drop is typical, and how much variation there is. For this kind of statistical data, which is absolutely required to draw this kind of conclusion, you'd need multiple studies each involving scores of athletes. Otherwise there's no statistical basis to decide what is normal and what is not. I admit at this point that I haven't done any research here. I have no idea of the number or quality of studies out there on this subject. But presumably Mørkebjerg is familiar with the studies, and yet he only mentioned a single study with seven riders. It may just be what fit in the article, but it doesn't inspire confidence.
Whether you like my hydration assumption or not, the fact that crit can change that much in four days without my doctor thinking it's significant says volumes about what these numbers mean.
In the entire month of the tour, the difference between Lances highest and lowest values was 2.4. Again, if mild dehydration accounted for my crit changes, just simple randomeness of hydration - when did Lance last pee and drink, how much is he sweating - could account for the variations we see. So on the issue of increases in crit after rest days, this data lies completely within the measurement noise. It would certainly be hard to argue for any kind of useful or measurable performance gain from such a small increase in blood values.
But even so one has to wonder what the natural effect of crit is from rest days. Certainly the obvious result during a rest day would be a drop in crit: your body no longer has all that waste to flush, and one presumes the athlete hydrates well, so the body will retain more fluid. This retained fluid translates into a larger blood volume without any increase in red blood cells. In other words, a lower crit. But then after another hard day of riding, does the crit jump back up to pre-rest-day values? Does it take a couple of days to return to those values? Or does it have an extra-quick rebound as the body is fully hydrated and willing to release fluids more quickly? I don't know the answer, but the point is, I'd hardly be surprised to see an influence on normal crit values from a rest day.
For the lack of attention this one has gotten, for my money it's still the most interesting of the three arguments. This probably says more about how uninteresting the other arguments are. At any rate, normal reticulocycte counts are around 1%, but with a lot of variation.
So the most interesting bit is that his reticulocytes are consistently low and yet his crit doesn't drop. Still, this isn't much of a sign of doping with crits this low. And, we have five days of tour blood values, meaning we don't know what his reticulocyte count looked like the other 17 days.
Red blood cells are produced in the marrow, and the body can request an increase in production by producing EPO. This tells the body to produce more red blood cells. But it also tells the body to release the cells that are already in production, even though they may not be "ripe". So it's entirely possible, even normal, to see a higher reticulocyte count for a few days, followed by a lower-than-normal count for a few days. It's a good argument for testing some of these blood parameters every single day during a tour, so you could actually make some meaningful statements about how the blood is trending.
There's no way to account for the fact that there's always some complex natural variation that for any practical purposes might as well be considered random.
The more interesting open questions would relate to statistical data on how much blood values are expected to drop during a grand tour, and how much that normally varies. In the absence of that data, the most interesting thing to say about Lance's published blood values is that they look very very normal.
At 2009/09/22 14:40|
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