Robin van Persie told Dutch broadcaster NOS he will need to "be honest" with himself as he contemplates his future with his contract at Feyenoord set to expire after the season.
Van Persie, 34, returned to his first club in January after leaving Fenerbahce, where he had played since his departure from Manchester United in 2015.
He scored his side's second goal in a 3-0 victory over AZ Alkmaar in the Dutch Cup final on Sunday and claimed his first major trophy in the Netherlands, but acknowledged afterward that continuing to play at a high level is getting increasingly difficult.
"There will come a moment where I have to be honest with myself -- like now," said Van Persie, who won 102 caps for Netherlands. "Today with the final, it turned out to be great for everyone, myself included, and I am very happy with that.
"But people don't see the other side, which is that for the last three weeks, I have been going to bed at 10 p.m. every evening and that I eat the right things at the right time. There is a lot that comes with being able to deliver today and sometimes that is a struggle. ... Sometimes the recovery takes a little longer than I want."
Van Persie, the longtime Arsenal striker who twice won the Premier League Golden Boot, scored his 300th career goal in Feyenoord's Dutch Cup semifinal victory over Willem II on Feb. 28.
He has made 12 appearances in all competitions for Feyenoord this season, scoring seven goals, and said he had agreed to speak with the club about a return in 2018-19 when he signed his current contract in January.
Feyenoord, he said, would like him to return, but he stressed he needs to make the most responsible decision.
"I also really want it, but you have to be honest and people don't see that other side," Van Persie said. "And sometimes it really is a struggle and I get tired of it myself, to be honest."
Van Persie suggested that he could return next season with the understanding that he rarely plays the full 90 minutes and instead is substituted off at the hour mark.
Still, he said, he doesn't regret the decision to rejoin Feyenoord, especially because he had the option to move to other clubs in January but wanted to return.
"I completely stand behind that decision and I am very happy with it," Van Persie said. "I am very happy with everything that has happened the last four, five months -- and I am not just talking about the matches, but also how the guys have received and supported me.
"I am working with the guys. I want to help them ... [and] I would like to play until I am 40. I am really happy the last [few months] and we will see what the future holds. Time will tell."