• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!


Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

Farmer Mat

New Member
May 5, 2003
hello its me again....
another question from me to our apnea experts....
what does this this ratio excactly show?
does a context exist between freediving and the hematocrit-value?
thanks once again!!
greets and good night...
percentage of packed red blood cells in whole blood.

if you spin blood in a centrifuge it will split into two main parts. densely packed RBCs and watery plasma. if you have a 10cm test tube then the bottom 4-5cm will be RBCs and the remaining upper part will be plasma. i.e normal hematocrit is typically 40-50%

higher hematocrit means you can store more O2 in your blood. so generally speaking higher hematocrit should improve freediving performance.

increasing your hematocrit without doping can be a very difficult thing to do. it's much easier to improve your performance by working on your technique, diving regularly and analysing your diving carefully. i.e. minimising O2 consumption, rather than increasing O2 storage.

you don't need very high hematocrit/hemoglobin to dive to world class standards. many world class divers have normal/average blood stats. e.g. Sam Still (my buddy) who did 68m in Vancouver yesterday (one the best cold water freedivers in the world) has a Hb of around 15g/dl... perectly normal/average. (generally your hematocrit is about 3 x your Hb... e.g. Hct 45 = 3 x 15 g/dl.)

you can increase your hematocrit by taking EPO. this can boost it up to 55-60%. such levels can be dangerous because the blood becomes very viscous and the heart has to work harder to pump it around the body.
Thank you Alun

hi alun,
thanks for your helping answer... i wasn`t sure about how important hematocrit is for freediving and what it is excatly!
i have to hurry with starting my training, if i want to be able to present result at the end of it....
so thank you once again for your fast answer
greets mat
DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


ISSN 1469-865X | Copyright © 1996 - 2024 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Ocean Advocacy and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.