The problem could be over-breathing, i.e. exhaling too much CO2. This lowers the blood CO2/bicarbonate levels and inhibits the oxygen release from hemoglobine (https://en.wikipedia.org/wiki/Bohr_effect).
The remedy is to breath less, both less frequent and less voluminous. Very little breathing is needed to saturate the blood O2 levels, as can be checked with a simple pulse oxymeter.
The remedy is to breath less, both less frequent and less voluminous. Very little breathing is needed to saturate the blood O2 levels, as can be checked with a simple pulse oxymeter.
Also see https://en.wikipedia.org/wiki/Buteyko_method