Oscar Award-winning actress Viola Davis recently revealed that she feared having a heart attack while training for The Woman King.

Davis shared her thoughts about the intense training she endured for The Woman King on an episode of The Tonight Show Starring Jimmy Fallon.

“Let me tell you something,” she told Fallon. “I was 56 when I trained to be this warrior…Five hours a day, hour and a half of weight training, three and a half hours of martial arts, punching, 10.0 on the treadmill.”

The actress continued, describing how she felt while running on the treadmill.

“And as I was running on the treadmill, Jimmy…I said [to myself], ‘I’m gonna have a damn heart attack.'”

Davis joked that if Fallon was ever in trouble, she could help because she had to do things like look at a “250-pound man with a machete” charging at her during training.

“There is nothing like looking at a 250-pound man with a machete coming at you,” she said. “They yell action, and that’s it. You are on that man. You have your sword, he has his, and you’ve got to do it. You gotta take care of yourself.”

Davis plays the role of a heroic female general named Nanisca in The Woman King. The film is a historical epic about the Agojie–a group of female warriors who reportedly protected the West African kingdom of Dahomey during the 1800s. It was directed by film director and screenwriter Gina Prince-Bythewood–best known for directing Love & Basketball, among other movies–and shot in South Africa. The movie also stars award-winning British actor, who portrays tribal King Ghezo.

Davis said The Woman King gathered dust before it was put into motion, but thankfully it’s finally in theaters.

“You gotta see it because let me tell you something,” she encouraged Fallon and his show’s live audience. “From the very moment the movie opens, you are on a ride.”