Project 454852

We all know someone who has fainted, but some people faint regularly (even daily) which negatively impacts quality of life and increases healthcare burden (repeated emergency room visits, large management team). Fainting occurs when the heart cannot pump enough blood to the brain. Typically, this happens when standing still, because gravity pulls blood into the lower body, reducing the return of blood to the heart. However, even when we stand still our body subconsciously sways to help with balance. We want to know whether muscle contractions associated with sway prevent fainting by "pushing" blood to the heart against gravity. In addition, emotional reactions can sometimes cause fainting, such as seeing blood or have blood drawn. In these cases, fainting might be triggered in the brain, rather than the heart. We will test: (i) What is the role of sway in preventing fainting? and (ii) What is the role of the brain in triggering emotional faints? In the lab we will test whether different sway patterns produce different cardiovascular responses. In the field with the British Army, we will determine whether sway can prevent fainting during military parades when soldiers are required to stand still for long periods of time. Using wearable sensors in real-life parades, we will compare heart rate, blood pressure, and sway patterns in soldiers who faint compared to those who do not. We will also work with people who faint from seeing blood or with needles. While having their blood pressure, heart rate and brain activity monitored, participants will watch a video of a blood draw and then have their own blood drawn. By comparing their brain activity to people who do not faint during these events, we can see if the brain actually initiates fainting. Together, these studies will allow us to understand fainting better and help us create preventive strategies to avoid it, which will ultimately be better for our healthcare system, and improve quality of life for people who faint.