Mertesacker is to retire at the end of the season and become Arsenal’s new academy manager.
But the German has revealed how he is both physically and mentally at the end of his career already.
Mertesacker says he cannot bare the pressure of playing anymore and feels physically sick before every match he plays.
He revealed he then “chokes so violently until my eyes water”.
“Everyone says I should enjoy the last year, to play as much as possible and take everything in,” Mertesacker told Spiegel.
“But I would rather sit on the bench or even better in the stands, and then, for the first time in my life, aged more than 30, I will feel free.
“Some days you realise everything is a burden, both physically and mentally but you have to deliver without a doubt.
“The pressure is very intense. I always have this horror story in my head, to make a mistake and be responsible for a conceded goal.
“If the fans celebrate it is great, it is unbelievable. But if they are booing you, I always feel very ashamed.
“In the moments before a game starts, my stomach turns around as if I had to vomit.
“Then I have to choke so violently until my eyes water.”
Mertesacker continued by saying he has thought about retiring several times in the past.
“At times I really was done,” the Arsenal man added.
“My body was not ready for any more efforts. And if I couldn’t play anymore, I was injured, it always was like that.
“I think, that a lot of returning injuries have psychologically reasons. That the body tries to give your soul some rest.”