If you’ve ever been short on blood, you know what it is to feel rotten.

Too little blood coursing through your body can leave your head pounding and your lungs laboring. Simple physical tasks like climbing a flight of stairs may become impossible feats of endurance.

And if you were fortunate enough to receive a blood transfusion, you can also appreciate the relief it brings. The change is sudden and miraculous.

Despite the insight that comes with a loss of blood, you’re better off without the experience. And it’s better still to avoid what happened last month to Jenapher Blair, the mother whose delivery in a small-town Minnesota hospital suddenly took a life-threatening turn.

After her baby was born, Blair began to hemorrhage, and the Hutchinson Health Hospital didn’t have enough blood on hand to replace the massive amount she was losing. She might have died.

She didn’t, thanks to quick action by the Minnesota State Patrol, whose troopers delivered four units of blood from St. Paul to the Hutchinson hospital in just over an hour. Tag teams of troopers conveyed the blood by car, helicopter and car again.

An officer said the State Patrol performs almost 100 blood or organ delivery runs every year.

The patrol’s performance seems nothing short of remarkable, and yet it wouldn’t have been possible if the American Red Cross had been unable to supply the blood in the first place.

Blood reserves in Minnesota and around the country are low. Demand is high, in part because hospitals are resuming elective surgeries that had been delayed by the COVID-19 pandemic. Demand is also up among trauma centers.

Add to these factors the extraordinary burdens imposed by disasters such as Hurricane Ida, which struck the Gulf Coast on Sunday.

“There is a critical need right now,” said Sue Thesenga, a Red Cross spokeswoman. “The blood is going out faster than it’s coming in.”

Thesenga added that her organization is delivering blood products at a rate 12% higher than at this time last year. She explained that the nation’s supply needs continual replenishing; blood products don’t have a long shelf life.

The Red Cross aims to keep a five-day supply available and ready to go should the need arise. To meet that standard, the Red Cross needs a steady stream of donors willing to roll up their sleeves. Happily, more than one-third of Americans meet the eligibility criteria to donate blood. Less happily, fewer than 1 in 10 of those who are eligible actually do so.

It may be that common misconceptions are to blame.

Some people mistakenly think that tattoos disqualify them from giving blood, or that chronic conditions such as diabetes make their blood unwelcome.

Still others may simply not realize how great the need is, or how universal: Every two seconds, someone needs a transfusion.

And to put a human face on that need, consider Jenapher Blair, who recently thanked troopers in person for ensuring that her three kids would still have their mother.

By intriguing coincidence, Blair’s procedure was an echo of the very first successful human blood transfusion: also to save a hemorrhaging mother after a delivery in 1818.

Luck must have played an outsize role that time, because researchers had not yet recognized the need to type and cross-match blood. It would be nearly a century before that discovery made blood transfusion safer.

Now another century has passed. This would be a good time for one more therapeutic advance: a larger supply of eligible donors, ready and willing to help.