Can a concussion affect your blood pressure?
A concussion can disturb the reflex that keeps blood pressure steady, called the baroreflex. Studies have found it altered in the first week and still changed months to years later, with blood pressure slower to settle after a challenge. That shows up as swings when you move more than as a constantly high number. A reading that stays high needs a physician.
What Keeps Blood Pressure Steady in the First Place?
Baroreceptors are some of the most important sensors in the body. They detect the pressure of the blood moving through the arteries, especially in the carotid arteries of the neck, and they're what allow you to move and stand. Every time you sit up, lie down or turn your head, pressure changes, and blood has to be redirected to the head within a beat or 2.
The reflex is a chain. The sensor detects the change, a nerve carries the signal to the brain, an area of the brain processes it, and the output adjusts heart rate and the tightness of the blood vessels. For the system to work, the whole chain has to be intact, and a fault at any link disrupts it.
What Does a Concussion Do to That Reflex?
Our team finds that in people with brain injuries and concussions, and with infections that affect the nerves or the sensors themselves, this reflex is suppressed or disrupted and becomes less sensitive than it should be. When it isn't sensitive enough, blood pressure starts to fluctuate. Each time you move, the response can come late or miss the mark.
Research has measured the reflex after concussion, with results that agree on a change and differ on the details. In 10 college athletes tested within 48 hours of a concussion and again a week later, baroreflex sensitivity was lower than in 10 uninjured athletes, while resting heart rate and blood pressure looked the same. The authors speculated that the fault lay in the brain's handling of the signal more than in the sensors (La Fountaine, 2019). A study of 30 athletes compared with their own pre-season baseline also found baroreflex sensitivity and blood pressure variability altered in the first 5 days, though in that study sensitivity went up (Ellingson, 2022).
The longer view comes from 25 people who were 4 to 98 months past a mild traumatic brain injury and otherwise healthy. At rest their baroreflex sensitivity was lower than in 29 controls. When the reflex was loaded with a Valsalva strain, their blood pressure took longer to come back down afterward (Hilz, 2016).
A systematic review of 39 studies in adults concluded that altered autonomic function has been reported both early and in the chronic stage after a mild brain injury, and that the studies are too limited to say how severe it is or how long it lasts. It rated 28 of the 39 as unacceptable in quality (Mercier, 2022).
Does a Concussion Cause High Blood Pressure?
The measured effect is on control, and resting pressure often looks normal. In the athlete study, resting systolic pressure was the same in the concussed and uninjured groups while the reflex was impaired (La Fountaine, 2019). So a concussion is better supported as a cause of blood pressure that swings, overshoots or settles slowly than as a cause of a number that's high all the time.
That matters for what to do with a home reading. A single high value after standing up fast, during a headache or under stress fits the swing pattern. Readings that are high at rest, sitting quietly, on several days are a question for your physician whatever the cause, because sustained high blood pressure is treated on its own terms.
Blood pressure in the arm is also a different measurement from pressure inside the skull. If the feeling is fullness or pressure in your head, that's covered on head pressure after a concussion.
What Does a Faulty Reflex Feel Like?
In our team's experience people describe lightheadedness or a head rush on standing, a pounding heart or a wave of pressure in the head when they move quickly, and readings that differ a lot from 1 check to the next. When the heart rate climbs on standing as well, the pattern overlaps with POTS, which is covered on can a concussion cause POTS. Symptoms that flare with specific triggers are on why concussion symptoms come and go.
How Is It Checked?
Our team's view is that the baroreflex isn't checked often enough, and that it should be looked at in every autonomic case where the blood pressure response is affected. A resting reading doesn't show it. In the research, the problem appeared when the system was challenged: beat-to-beat pressure during a Valsalva strain, or the relationship between each change in pressure and the heart's response (Hilz, 2016; La Fountaine, 2019).
In our team's exam that means watching heart rate and blood pressure with posture and with effort, and finding which link in the chain is failing: the sensor, the nerve, the processing in the brain or the output. What our team measures after a concussion is on concussion testing: what to expect.
Go to an emergency department for a very high reading together with chest pain, severe headache, confusion, trouble speaking, weakness or a change in vision.
See how we test it in 3D
Tour the testing our team uses to find which systems are struggling.
Take the 3D TourHas your blood pressure been unpredictable since a concussion? See how our team finds what's driving it and treats post-concussion syndrome.
Post-concussion treatment at the clinicBlood Pressure After a Concussion: FAQ
Can a concussion cause high blood pressure?
The research shows a change in blood pressure control more than a constantly high number. In athletes within a week of a concussion the baroreflex was impaired while resting blood pressure matched uninjured athletes (La Fountaine, 2019). A reading that stays high at rest should go to a physician.
Can a concussion cause low blood pressure or dizziness when standing?
A less sensitive baroreflex can respond late when you stand, which our team sees as a dip and lightheadedness. People months to years after a mild brain injury had lower baroreflex sensitivity than controls (Hilz, 2016).
How long do blood pressure changes last after a concussion?
Changes have been measured in the first week (La Fountaine, 2019) and in people 4 to 98 months after injury (Hilz, 2016). A review of 39 studies concluded that the evidence can't yet say how long they last (Mercier, 2022).
What is baroreflex failure?
The baroreflex is the chain that senses blood pressure in the arteries and adjusts heart rate and vessel tone to hold it steady. Our team uses the term for a reflex that has become less sensitive at the sensor, the nerve, the brain's processing or the output, so blood pressure fluctuates with movement.
Should I monitor my blood pressure after a concussion?
A resting reading can look normal while the reflex is impaired (La Fountaine, 2019), so home checks won't show the whole picture. They're still useful for catching a number that stays high at rest, which is a reason to see your physician.
Sources
- Hilz MJ, Liu M, Koehn J, et al. Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury. BMC Neurology. 2016;16(1). doi:10.1186/s12883-016-0584-5
- La Fountaine MF, Hohn AN, Testa AJ, et al. Attenuation of Spontaneous Baroreceptor Sensitivity after Concussion. Medicine & Science in Sports & Exercise. 2019;51(4):792-797. doi:10.1249/MSS.0000000000001833
- Ellingson CJ, Singh J, Ellingson CA, et al. Alterations in Baroreflex Sensitivity and Blood Pressure Variability Following Sport-Related Concussion. Life. 2022;12(9):1400. doi:10.3390/life12091400
- Mercier LJ, Batycky J, Campbell C, et al. Autonomic dysfunction in adults following mild traumatic brain injury: A systematic review. NeuroRehabilitation. 2022;50(1):3-32. doi:10.3233/NRE-210243