The 24-year-old has had a near non-stop schedule over the past two months, reaching the closing rounds in tournaments as the circuit moved from hardcourts to the clay season, winning titles at Indian Wells, Miami and Monte Carlo.
"I've played a lot in the last one and a half months, going very deep in tournaments," Sinner told reporters after defeating Arthur Fils 6-2 6-4 in the Madrid semi-finals on Friday.
"It's a good sign, of course, and at the same time you tend to get a little bit more tired.
"I think and I believe, when I play big matches, semi-finals, quarter-finals, finals, there's also a little bit of adrenaline that pushes me."
Victory over Alexander Zverev in Madrid on Sunday would hand Sinner a fifth successive Masters 1000 title going back to Paris last year and further underline his strong start to the clay season, with the French Open beginning on May 24.
With defending Roland Garros champion Carlos Alcaraz ruled out due to a wrist injury, world number one Sinner will be the top contender in Paris, where he can complete the career Grand Slam, having won the Australian Open, U.S. Open and Wimbledon.
For now, however, Sinner's focus remains on Madrid and next week's Italian Open in Rome.
"I'm of course very happy to play my first final here. It means a lot to me ... whatever (happens) on Sunday, it has been a great tournament," Sinner said.
"In between here and Rome I'll try to recover again as much and then we'll see."