When people become overweight or obese their blood volume increases because of fluid retention. Now that such a high (and rising) proportion of the population is obese, the average person's blood volume must be quite a lot more than 8 pints.
But it would be very difficult to get this checked out because there is some risk of harm from the blood measurement procedure and so health professionals rarely do this measurement.
Lose weight by eating less salt! Go on! - Try it! - You will feel so much better!
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