Alonso walked away from F1 for two years at the end of 2018 after growing tired of media and commercial commitments while his McLaren team fell into the bottom half of the standings.
In his time away, he twice won the Le Mans 24 Hours, chalked the 2018-19 World Endurance title and contested the Indianapolis 500 before returning to F1 with Alpine in 2021.
Despite turning 42, a 2023 season at Aston Martin returned him to the podium eight times to boost his motivation further.
He said: "To be competitive, to feel the speed again, and to arrive to the weekend again knowing that you need to do everything perfect because there is a podium possibility or a race win possibility, that really gives you a very different approach and a very different love for the things you do and dedications."
But the two-time champion concedes that F1's punishing schedule could be the factor - rather than age leading to a decline - that prompts him to quit again.
Alonso reckoned: "I said many times even before 2018, the day that I will stop racing is not because I feel not motivated for driving or I feel slow.
"If I feel slow one day, I think it will be noticeable and think I will not be happy with my performance and I will be the first one to raise my hand and say 'this is time [to stop]'.
Source: Autosport