Hematòcrit levels

[nurul]

Just found out today that my hematocrit level is 47,2. However the blood test was done at 830am in the morning when one is dehydrated and. I did the test 50 mins after having left the bed at 830am. Apparently if you are dehydrated your HL will be higher than normal. In that case how effective and accurate is having a blood test when you haven't breaksfasted, in order to measure hematocrit levels?? Also 47,2 I presume is pretty handy in cycling but what other factors must I take into account apart from weight and Vo2 max?? I know that 50%+ is illegal according to the UCI so as a stand alone figure 47,2 must be good???

 

[Feltski]

A Hematocrit of 47% is almost dead center in the range for adult males. It is true that dehydration will cause a slight false increase, however I am not sure to what extent, but I would imagine no more than 1% if even that.

 

[Denia]

A Hematocrit of 47% is almost dead center in the range for adult males. It is true that dehydration will cause a slight false increase, however I am not sure to what extent, but I would imagine no more than 1% if even that.

I don't think that is correct, I think the average is closer to 42-43% for a male. It fluctuates in cycling by going down during bouts of hard effort e.g. during a 3 week TdF it should decrease. I have had several tests in the last 18 months and mine varies between 45-48% depending mostly on how hard I have been riding.

It certainly is an advantage, however small, if you have a naturally high hematocrit level but it is not a shortcut to any type of success unless the main key elements are taken care of - fitness, weight, nutrition, tactics etc.

 

[Denia]

Some interesting stuff from www.CyclingNews.com website:

Hematocrit is the proportion of your blood that is red blood cells. As a result, anything that affects blood volume or blood flow will interfere with the ability to accurately measure hematocrit. Dehydration decreases plasma volume without changing red blood cell mass, so it artificially elevates hematocrit. Posture also changes hematocrit measurements. Standing upright causes fluid to leave the blood and enter the space between cells, concentrating the blood and increasing hematocrit. Acute exercise also increases hematocrit for approximately 1 hour after exercise. Time of day also has an effect with morning measurements typically being 2-5% higher than evening values. Because hematocrit is sensitive to these factors, it is important that it be measured under standard conditions.
Hematocrit is normally distributed within the population and the distribution in endurance athletes is comparable to the general population. In the United States the average hematocrit for men is 45% and 39% for women. One study of 1628 blood samples from 69 male and 55 female elite cyclists found that the means and standard deviations for hematocrit were 45 ± 2.9% and 40.7 ± 2.7%. The average hematocrit in samples taken at the 2000 Tour de Suisse was 44.5%. Within an individual there can be a true increase in hematocrit of up to 10% with endurance training or altitude exposure. There also seasonal variation in hematocrit with averages 3% lower in the summer than in the winter due to expansion of plasma volume.

The 50% rule was set based on hematocrit distribution in the population and average values for elite male cyclists. Because only 3% of the population naturally has a hematocrit greater than 50%, values exceeding 50% can be considered abnormal. It should be noted that a hematocrit >50% is not definitive proof of blood doping by any method.

 

[JAPANic]

2006 47.7
2008 50
2009 ?

http://www.cyclingforums.com/t461496.htmlSimilar thread I started last year.

 

[JAPANic]

2009 51.1%

I swear, I'm clean.....