Khloé Kardashian's workouts create an "after-burning" sensation, according to personal trainer Gunnar Peterson.
The American fitness instructor trains the majority of the Kardashian/Jenner clan has admitted he tailors the 'Kocktail with Khloé' host's exercise sessions to include high intensity elements, which include squats and jumps on an inflated mat, to leave the TV personality with a severe aching feeling in her muscles.
Speaking on UK TV show 'Lorraine' about the 31-year-old's gruelling regime, Gunnar said: "Anything that's going to create an after-burning effect. Working your heart rate, it is high intensity. Now a basic squatting motion one at a time and five little hops."
However, due to Khloé's busy routine their workouts can be sporadic.
He explained: "If her schedule says five am that is what it is, and if her schedule says it's a day where she has a late circuit then she will be here at 10 or 11."
Gunnar has revealed his clients also include the 60-year-old momager Kris Jenner, Rob Kardashian, 29, and 20-year-old model Kendall Jenner.
The exercise expert has known the family for a long time and takes great pride in getting them in great shape.
He said: "I'm fortunate enough to have known them for years. I've worked with Kris for years, Kourtney for years, Khloé for years, I see Kendall and I see Rob."
Although Khloé pushes herself to the limit when exercising under Gunnar's guidance she always wears a pair of hoop earrings and make-up to the gym to make her feel "cuter" when she's sweating.
Speaking previously, the 'Keeping Up with the Kardashians' star said: "I always wear hoop earrings; they're like my security blanket. People laugh at me, but why not? They make me feel more dressed up.
"I also wear make-up when I work out. I put on a tinted moisturizer, mascara, and cherry lip balm, and fill in my eyebrows. If I feel cuter with a little lip colour and mascara, why should anybody else care?"