It is a common misconception that the heart and the brain are separate parts of the body, the work together in order to keep the body in a constant state. Your heart is controlled by the autonomic nervous system and is responsible for speeding up and slowing down your heart rate. Particularly the Vagus nerve, as seen in the picture, can send messages from the brain to the heart and from the heart to the brain. In essence, this means that by measuring information from our heart we can start to understand processes in the brain. This is typically done through the use of heart rate variability (HRV).

HRV is the time interval between each heartbeat. Therefore, by measuring HRV we can understand which part of the nervous system is controlling your heart rate. Understanding nerve control of the heart is particularly important as we can index what is happening in a particular area of your brain, the prefrontal cortex. This area is linked to the heart through the Vagus nerve and therefore activation of this nerve, known as vagal activity, links to activation of this area of the brain. Higher levels of vagal activity have been linked to many benefits associated with sport such as emotion regulation, decision making and performing under pressure. Therefore, using HRV is far more than just heart rate, it allows us to understand brain-body interactions, which are essential for effective performance.