Multiple concussions negatively affect heart activity, and brain oxygen levels–and may be associated with symptoms such as headaches
By Ella Gullickson. This article was initially published in the 1/11/24 edition of our Concussion Update newsletter; please consider subscribing.
A team of researchers from the University of Regina and the University of Saskatchewan wrote an article for The Conversation about their ongoing studies of the “interaction between the heart and the brain,” called the heart-brain axis. Concussions, they write, alter signals to the heart. Singh et al. found that concussion can alter heart function through an upset to the autonomic nervous system (ANS), part of the nervous system in charge of involuntary body processes, such as the heart beating, breathing, and digestion. The authors and many other researchers have documented decreased heart rate variability related to ANS dysfunction after a concussion; heart rate variability is the time between beats, and less variability means the body is less able to respond to physical demands. Jyotpal Singh, J. Patrick Neary, and Payam Dehgani also write about CBD as a potential concussion treatment for this dysfunction, research for which their team recently received funding from the NFL.
Also part of this picture is blood pressure, comprised of the heart contracting (the systolic measure) and relaxing (the diastolic measure)––two phases in a blood pressure reading. When there is a disruption to the ANS after a concussion, the researchers have observed reduced strength of each heart contraction (reduced systolic pressure) and suppressed blood pressure variability. These complications can lead to reduced oxygen to the brain and, therefore, altered brain activity. The authors state, “Concussion symptoms such as headache and pressure build-up in the head reflect the ANS not working properly.”
Typically, changes to the heartbeat and blood pressure after concussion go away with recovery. However, Singh et al. suggest that “a history of repeated concussions can have long-lasting effects. Specifically, those with a history of at least three concussions show altered oxygen activity in the brain.”
In the lab, Singh et al. analyzed several case studies: one male with a history of multiple concussions who all had heart complications and four females suffering from persisting symptoms after a concussion. They found that when a cardiologist treated the male for heart issues, the medication, amiodarone, also alleviated all concussion symptoms in days. This study is the first to report treatment for concussion symptoms through treatment of abnormal heartbeat, so research is still limited.
The four females with post-concussion syndrome were found to have decreased systolic blood pressure variability; they were included in the researchers’ new study into compounds from the cannabis plant (cannabidiol or CBD) for concussion treatment. Under the guidance of a physician, the female patients with persisting post-concussive symptoms, aged 42-52, consumed CBD oil. As a result, their systolic blood pressure variability and their concussion symptoms improved. Thus, the research team suggests that “cannabinoid therapy may have a beneficial effect on concussion recovery.”
