Blood Donation and diving

[billeelou]

58 days between blood donation...oxygen enrichment for long distance runners...We all know that the red blood cells carry oxygen and yet an article I read says donating blood reduces the viscosity and so better delivers oxygen... so what length do you delay after donating?

 

[divingjd]

Covered in the "No Dumb Questions" feature of Dive Training Magazine in January (see http://www.dtmag.com/01-06-NoDumbQuestions.shtml). The experts (including DAN) recommend 48 hours minimum, with 72 hours preferred. The increased viscosity also poses greater DCS risk - one of the reasons dehydration increases DCS risk.

 

[KrisB]

58 days between blood donation...oxygen enrichment for long distance runners...We all know that the red blood cells carry oxygen and yet an article I read says donating blood reduces the viscosity and so better delivers oxygen... so what length do you delay after donating?

funny, as a "doping" method in several sports, athletes will attempt to gain an unfair advantage by "donating" their blood several months before the competition, then having it re-transfused back into them just prior to the competition.

Somehow I think the viscosity argument is one used to persuade people to donate...

 

[agilis]

Some athletes use autologous transfusions, essentially the reintroduction of their own previously extracted and preserved red blood cells into their blood, to enhance the O2 carrying capability of their blood. I understand that this is most useful at high altitudes, where the air itself is thinner. It is, at best, frowned upon by sports medicine specialists, and is regarded in some sports as illegal. The effect is of limited duration as the bone marrow, spleen, etc, stabilize blood composition. For divers, the slight thickening of the blood and the increase in its viscosity following such transfusion can negatively affect offgassing. The effect can mimic the symptoms of polycythemia, a serious medical condition characterized by too many red blood cells. People with this disease have lots of problems. Draining blood every few weeks is a common treatment, because it reduces very dangerous blood viscosity.

The 2 or 3 day wait after donating a pint of blood is due to the slight weakness and dehydration associated with blood loss. The general advice I've gotten after donating blood is to to drink lots of fluids, something all divers should do anyway, to make sure they are not dehydrated, a definite risk factor in decompression sickness.

 

[ScubaTexan]

Covered in the "No Dumb Questions" feature of Dive Training Magazine in January (see http://www.dtmag.com/01-06-NoDumbQuestions.shtml). The experts (including DAN) recommend 48 hours minimum, with 72 hours preferred. The increased viscosity also poses greater DCS risk - one of the reasons dehydration increases DCS risk.

I wish DAN would supply that information to my local blood donation center. On their card, they say to refrain from scuba diving for 12 hours. No thanks -- I can wait... :11:

 

[billeelou]

Just came back from the Blood donor place, yep their card says 12 hours too!! but its ok, that trip to Mahahaul, Mx last January has killed my donating until 2007....oh well...maybe next year

 

[divingjd]

I've got the same problem with blood donations these days. Visit Roatan, or a part of the Yucatan outside of Cancun (i.e., any cenote), and I am prevented from donating for a couple of years. I used to donate all the time. These days, I can't.