Viser at CO2 øker aller mest de første 7 sekundene når man holder pusten.

http://www.ncbi.nlm.nih.gov/pubmed/3152423

An estimate of the logarithmic PaCO2 rise during breath holding at functional residual capacity was 7 mmHg during the first 10 seconds (43 mmHg/minute), 2 mmHg during the next 10 seconds (13 mmHg/minute), and 6 mmHg/minute thereafter. In conclusion, PaCO2 increases more rapidly in awake apneic humans than earlier thought.