Personal assistant and physio Cullen spent seven years alongside Hamilton in the paddock, a crucial part of his inner-circle and a trusted confidante.
But she left her role, and has been replaced by new people, although the professionalism she taught Hamilton has not been forgotten.
"My recovery is better,” the Mercedes driver, now 38, said.
“I'm more focused on recovery than I ever was before.
"When I was 22, I wasn't focused on recovery. I didn't even know anything about recovery.
“I was just going home, probably having a pizza, not knowing what I needed to do the next day.
"For recovery, I didn't have any specialists around me to help me navigate that.
"I had a physio, but we didn't do a huge amount. We did some training together, we did some swimming together.
“But otherwise I didn't have all the details of how you want to eat, how to replenish the liquid you lose, stretching, all those different things.
"I wasn't doing that back then. But I don't know if those drivers back in the day were that fit, so they probably fell off more than us because we train a lot more than they did back then."
Hamilton is now the second-oldest driver on the F1 grid, behind 41-year-old Fernando Alonso.
Hamilton’s F1 career is likely to stretch into his 40s as he plots a new contract to stay with Mercedes, although it remains unsigned.
He will start the F1 Miami Grand Prix from 13th after yet another nightmare session in the troublesome W14.
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