Every week Mrs May tests herself to the limit with the support of Reading-based instructor Lee Carnaby between Brexit talks and Prime Minister’s Question Time.
She goes through a high-intensity, full-body workout and sessions include weight-lifting, resistance training and squats.
CrossFit specialist Mr Carnaby, who has been operating his own personal training business since 2005, has trained everyone from MPs, ex-Special Forces to professional footballers.
Theresa May is keeping in shape with the support of instructor Lee Carnaby
A source said: “Theresa sees Lee once a week, and loves it.
“She is incredibly dedicated and sessions are built into her agenda; she refuses to miss them unless she is out of the country.
“Lee has been doing a lot of squat work with Theresa, in addition to vigorous HIIT (high intensity interval training) sessions which raises her heart through the roof, but burns fat spectacularly.
She works out with the CrossFit specialist between Brexit talks and Prime Minister’s Question Time Theresa May's candid pictures Sat, July 23, 2016
A candid look at Prime Minister Theresa May's childhood and family life in pictures.
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“Lee is also a Crossfit specialist and incorporates some of this into her workouts with weights and heavy resistance training.
She is incredibly dedicated and sessions are built into her agenda
“Theresa feels and looks amazing.”
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Mr Carnaby charges £45 an hour for the sessions and said his “passion is changing people’s lives and transforming both people’s physiques and their perception and enjoyment of exercise.”
Mrs May said she was forced to change the way she lived after being diagnosed with Type 1 Diabetes
Mrs May said she was forced to change the way she lived her life back in 2013 after she was diagnosed with Type 1 diabetes.
She added: “The diabetes doesn’t affect how I do the job or what I do.
“It’s just part of life- so it’s a case of head down and getting on with it.
“It was a real shock and, yes, it took me a while to come to terms with it.
“There was weight loss but then I was already making an effort to be careful about diet and to get my gym sessions in.
“It doesn’t and will not affect my ability to do my work.
“I’m a little more careful about what I eat and there’s obviously the injections but this is something millions of people have.
“I’m OK with needles, fortunately.”