The fiery Italian admitted after Saturday night's 1-0 defeat to Manchester City in the Barclays Asia Cup final he had been driving his players hard.
Di Canio is of the belief the Black Cats had it too easy under Martin O'Neill, to the extent some of his squad were "under trained".
There is no chance of that happening this time around, with Di Canio imposing a punishing schedule on his squad, who now head for home ahead to continue preparations for the opening Premier League fixture with Fulham on August 17.
But Gardner is not bothered as that is just the way he likes it.
"It is tough, I admit it," said the 26-year-old.
"But it is a good tough because training is hard.
"I am a firm believer that the attitude to training should be the same as it is in life generally.
"If you work hard in life you get a good life. That is what we are doing as far as training is concerned, so hopefully we will have a good season."
Gardner has been linked with a move to West Brom as Di Canio's new-look squad begins to take shape.
A former Aston Villa and Birmingham player, such a move would complete a strange treble.
Yet Di Canio has used Gardner extensively in Sunderland's pre-season campaign, including Saturday night's match when the versatile Solihull-born player slotted in at full-back.
Gardner proved his worth too, making two superb goal-line clearances, including one where he knew preventing City from scoring would result in him clattering against a post.
"I'm no hero," he said.
"I am just doing my job. I will take a bruised head to stop a goal. It is what I get paid for."
Gardner is happy enough though, even if his more usual position is further up the field.
"I just want to play as many games as I can this season, no matter what position it is," he said.
"I would rather play anywhere than be on the bench.
"I am playing in pre-season. I have played four full games and I am enjoying it."
Sunderland, meanwhile, confirmed that midfielder Alfred N'Diaye has joined Turkish side Eskisehirspor on a season-long loan.
The 23-year-old France youth international has made just 16 appearances for the Black Cats since his arrival from another Turkish club, Bursaspor, in a £3.8million deal in January.
N'Diaye's move continues the changes being made by Di Canio at the Stadium of Light.
The Italian has made nine new signings this summer and allowed six players to leave permanently while Danny Graham, and now N'Diaye, have moved out on loan.