Calgary's emergency crews are rolling up their sleeves for the annual blood drive "Sirens for Life," to encourage more donors to come forward during a time when there is a need for more donations.

It's a friendly and timely competition between emergency medical services, police and fire departments, said Judy Jones, associate director of Canadian Blood Services. Jones said 550 new donors, or 5,000 units of blood, are needed just to meet the hospital needs in southern Alberta in January alone.

"It's a good opportunity for the first responders to give back and make an impact in the community," she said.

Typically an average of 500 new donors are needed every month.

She also said the way people are donating has changed. Regular donors usually make six appointments a year, but newer donors make about half that.

Carol Henke of Calgary Fire Department donates blood

Carol Henke is a repeat blood donor, after receiving two blood transfusions after a motorcycle accident in her teens. "You never know when you or your family might be impacted." (Monty Kruger/CBC)

"I think it's just not top of mind. A lot of older donors may have seen the need. They may have had a family that has needed blood or blood products," said Jones.

Calgary's emergency officials see the need first-hand when responding to calls.

"At the end of the day, we all know why this is important and donating blood is something that we can all do," said Nick Thain, executive director of EMS under Alberta Health Services.

Some people, like Carol Henke, realize the value of donating blood on a personal level.

"I was actually the recipient of two blood transfusions in my teens as a result of a motorcycle collision," said Henke with the Calgary Fire Department. "I just feel like I need to do this."

Police chief Roger Chaffin donated blood for the first time.

"I didn't cry or anything yet so it should be fine."

As for the friendly rivalry between departments about who can donate the most, Henke said, "I think we've got it in the bag."