How does repeated exercise impact your heart? To find out I spoke to St George’s University of London heart specialist Sanjay Sharma. He’s the medical doctor for the London Marathon, the England football team and Andy Murray…

• Professional athletes push themselves to the limits and regularly do more than 10-15 times the recommended amount of daily exercise.
• Athlete’s heart is a medical condition that involves up to a 20% increase in the thickness of heart muscles and a 10% increase in the size of the cavities in the heart.
• At rest the heart pumps 5 litres of blood around the body, whereas during exercise this can increase to 25-30 litres.
• Your heart behaves like any other muscle in your body and will increase or decrease in size depending on your level of fitness.

You can listen to the full interview for the Naked Scientists here.