It is always dangerous to lose blood. 4 units is no different. A persons body has to maintain a certain amount of blood in order for the heart and other organs to function properly.
How many units of blood are in a human
Maybe pints...
You can lose 4 pints of blood after that you're dead.
1,800 milliliters. One unit of whole blood is 450 milliliters (about .95 pints). Therefore, four units of blood is about 3.8 pints.
4 to 6 units
Depends on how soon you can reach medical care. If you lose more than 4 units (~4pints) of blood,You'll pass out then soon die of blood loss. Popping veins is not recommended.
4 units
4 liters, the human body holds 5 liters of blood. Now losing 4 liters is still technically survivable if the bleeding can be stopped right away.
This would be difficult to achieve in such a short timespan, and it would also be dangerous. It is unhealthy - and potentially dangerous - to lose more than 2-3 pounds per week.
One hour
It is 4 units.
3 units and 4 tenths is 3.4 units.