It will soon be 10 years that Martin Brady, 45, pictured, has held the accolade after he was tested at the Guernsey Chest and Heart Unit with a heart rate of just 27 beats per minute.
The average resting rate is between 60-100bpm.
He originally took the title of world's slowest heart rate from five-times Tour de France winner Miguel Indurain, who had recorded 28bpm.
But an 81-year-old from Surrey has recently claimed that he has a heart rate of 26bpm.
According to national reports, Dan Green, a former physical training instructor, contacted Guinness World Records about his heart status.
However, because of 'conditions impossible to achieve unless he had a well-heeled sponsor', Mr Green has decided to leave Mr Brady to 'enjoy his record'.
