Clifford, 56, has also dealt with heart problems in the past and had to undergo a procedure to insert two stents into his heart four years ago, but he says the headaches have been a far more worrisome, agonizing condition.
"This issue now, the headaches, was not even close to the heart," Clifford told ESPN's Adrian Wojnarowski. "That week before I stepped away, and that morning in the office, it scared me. It was much more significant than the heart was, and I've never had anything physically that concerned me as much as this did."
The cause of the headaches, it seems, was related to Clifford's lifestyle.
"For the most part, the diagnosis was sleep deprivation," Clifford told Wojnarowski. "The headaches and the cause of the headaches were a lack of regular sleep and the stress that goes along with coaching. There were two ways to treat it: Stronger medication or stepping away from coaching, stopping the travel, getting regular sleep, diet, and exercise.
"But getting on medication would only be a Band-Aid. It could get me through another day, a week, a month, but here was my decision: Long-term health versus coaching right now. The doctor told me, 'You may get through this season, but you're going to have migraines soon, and that's going to become a much bigger problem for you.'"
So Clifford stepped away from the game and focused on living healthier, a process that included training himself to sleep seven hours a night and take naps during the day until the headaches began to subside. Now he's preparing to immerse himself in coaching once again and he isn't afraid of lapsing into his old bad habits.
"I never, ever want to go through that again, feel that way again, and I don't believe I'll ever have to," Clifford said. "What doctors have done for me is not only given me a plan to help me feel better physically, but they've educated me on how headaches work. In my case, it's not just how I did the coaching thing, it's how I lived.
"I have to sleep more, and I have to train my body to sleep more. As the doctor told me, 56 is a little different than 50. The things I did when I was younger, well, the body is telling me I can't do that anymore."