Athletes have bigger hearts
Just like arm or leg muscles will increase in size with weightlifting, the heart muscle will grow with endurance training. The walls of the heart become thicker, and the chamber size increases. This gives the heart a greater capacity to pump blood throughout the body and deliver more oxygen to the working muscles. However, these changes will take months or years to occur.
Dr Bruce says: “An endurance athlete will have a resting heart rate of between 30-40 beats per minute compared to an average person, who might have 60-100 beats per minute. As the athlete’s heart is larger, it will not need to beat as often to deliver the same blood flow. One simple way to test for cardiac adaptations with training is to monitor your resting heart rate over time.”
Training also increases the number of red blood cells in the vessels. These cells carry and deliver oxygen to the various tissues of the body, including muscle. Alongside changes to the heart, an increase in the number of red blood cells will allow more oxygen to be delivered to the muscles during exercise, which is beneficial on race day.
Training will literally change your muscles
Training will increase the production of mitochondria (the powerhouses of the cell) in a runner’s leg muscles. Mitochondria are where sugars and fats are burned with oxygen to produce energy the muscle use to contract and enable a person to move. Training also allows the muscles to become more efficient at using oxygen, meaning a runner can run for longer at higher speeds.
These changes won’t happen overnight. The average professional runner might run over 100 miles in a week, and these adaptions to the body will take place over months of regular training. These transformations can still occur with less intensive training workouts, so novice runners should keep training.
The reasoning behind blood doping
The King’s Drug Control Centre (DCC) is the only World Anti-Doping Agency (WADA)-accredited lab in the UK and analyses between 10,000 and 12,500 samples from athletes a year, testing for prohibited substances.