Alonso put pen to paper on a multi-year deal with Aston Martin after mulling over his future options, a deal which will include driving in F1 for at least the 2025 and 2026 season.
Depending on whether Alonso will want to continue or not, that F1 deal can either be extended or converted into a non-driving role with the brand in what the Spaniard called a "lifetime project".
Alonso will turn 45 during the 2026 season and while the two-time world champion sees no signs of slowing down any time soon, he says he will be honest if he does feel he is losing any of his drive.
"It is true, I will be 45 or more and keep racing," he said. "If one day, I feel that I'm not motivated, not in good shape or not fast...I think I have a very honest relationship with Aston.
"I will be the first one to raise my hand and say: 'You know, I have maybe lost here or there' and we will find solutions.
"But I don't see that coming for the next few years. As I said in Japan, probably one of my best races ever maybe happened just five days ago, so I am feeling good. I don't see any problem there.
"And Lewis will turn 40 next year in January, so at least I will not be the only 40 plus that you will talk [about]!"
Alonso, who said retirement from racing in general was never an option, explained he used the hectic season start to question whether or not he wanted to continue his flat-out commitment to F1's relentless schedule with 24 races and off-track activities.
After the Australian Grand Prix, he made the decision to seek an extension with Aston Martin as he felt his love for F1 trumped his wariness of the series' demanding lifestyle.
"Obviously, Formula 1 takes all your time or your energy, you have to give up basically everything in life to keep racing," he elaborated.
"I needed a few races or a few weeks to really think for myself if I was ready to commit for more years.
"It was not a racing factor, it was more the traveling, to be honest. Looking at this calendar, I was a little bit afraid that this would be heavy on me.
"There are all the commitments pre-season with all the photoshoots, video, car launch. All these kinds of things are quite demanding for drivers, and for me particularly in this part of my career.
"So I said, let me go through that tough period at the beginning of the year and that tough period of traveling, time zones, big planes and these kinds of things.
He concluded: "I felt that I love too much driving, that I cannot stop at the moment. And I think the sacrifices that you have to make are smaller than the joy of driving and the passion that I have for driving.
"I breathe Formula 1, I live Formula 1, I train to be fit to drive Formula 1 cars, I eat to be fit to drive Formula 1 cars.
"And it didn't arrive, the moment that I felt I need to change the lifestyle. My lifestyle is great.
"I love what I do, so I will not be happy sitting at home and watching Formula 1 races because at the moment I still feel that I should be there."
