Someone can suffocate for 20 minutes. On average, people can suffocate for 30-60 seconds each time. This physiological limitation leads to a rapid accumulation of blood acidified carbon dioxide in myoglobin, but this is not hypoxia. Some divers can keep themselves underwater for a long time. The Guinness record holder of the free diving time Danish Stig Sheflinson can suffocate underwater for up to 22 minutes.