The secretary of the Army said Monday he has no doubt that soldiers will "rise to the challenge to meet the requirements" of the new Army Combat Fitness Test in October 2020.

The chief of staff of the Army put his views more bluntly.

"If you can't get in shape in 24 months, then maybe you should hit the road," Gen. Mark Milley said, referring to the Army's commitment to the new six-event ACFT.

"We don't want to lose thousands of soldiers to [the ACFT]. This fitness test is hard. No one should be under any illusions about it," he said. "But we really don't want to lose soldiers on the battlefield. We don't want young men and women to get killed in action because they weren't fit."

Milley made his comments to a group of defense reporters at the 2018 Association of the United States Army's Annual Meeting and Exhibition as the Army begins a large-scale field test of the ACFT.

Army Secretary Mark Esper said he has heard nothing but support for the proposed replacement for the current Army Physical Fitness Test.

"I have been here as secretary of the Army almost a year now. I have done physical training with nearly every division in the Army -- brigade combat teams, you name it -- I actually think the soldiers are ahead of us on this," he said. "I see soldiers out there doing ... the type of drills and exercises that will make them more fit on the battlefield. Everywhere I go, I ask them this question, 'What do you think about the Army Combat Fitness Test?' And hands down, you hear unanimous support for this move. They think it's the right thing to do. They know it will be tough, but they know it will also help them win and survive in combat."

The new ACFT has about an "80 percent correlation to the physical activity that is expected of soldiers in the execution of ground combat," Milley said.

"We want to make sure that our soldiers are ... in top physical shape to withstand the rigors of ground combat," he said.

Milley added that there was "nothing like" ground combat.

"Combat is not for the faint of heart, it's not for the weak-kneed, it's not for those who are not psychologically resilient and tough and hardened to the brutality, to the viciousness of it. We've got to get this Army hard, and we've got to get it hard fast."

Senior leaders acknowledged Monday that meeting the ACFT's new fitness standard will be a challenge.

"But as the secretary said, 'I have no doubt that when you put a challenge out in front of the American soldier, they are going to rise to the challenge,' " Milley said.

-- Matthew Cox can be reached at matthew.cox@military.com.