Why Do Concussion Symptoms Come and Go? 4 Hidden Triggers

Is It Normal for Concussion Symptoms to Come and Go?

Recovery after a concussion rarely runs in a straight line. When 79 children aged 11 to 17 rated their symptoms every day from the injury until they cleared, their paths split into 4 patterns, and for 52% the symptoms lasted longer than 14 days (Sullivan, 2024). For people months or years out, good stretches and bad stretches are what our team hears about most.

When symptoms feel like they come out of nowhere, you end up watching yourself all day, trying to work out what made you feel bad so you can stop doing it. That's a reasonable response. Our team's position is that the body is a machine, and things happen in it for a reason. Finding the cause helps your spirits, and it shows what to work on.

Why Would a Recovered Brain Still Have Bad Days?

Feeling better can come before the reserve is back. 1 study measured how well the brain's blood vessels respond when carbon dioxide levels change, a measure of how much room the circulation has to adapt. In college athletes it was reduced 3 days after a concussion and was still reduced at 21 days and at 90 days, even though their symptoms had cleared by day 21 (Purkayastha, 2019).

Our team reads that as a narrower margin. On an easy day you stay inside it and feel fine. Add a demand that pulls blood or processing away from the brain, and you cross the line. The trigger isn't always obvious, and that's why the symptoms look random.

Head turn Meal Heat Busy room

What Are the 4 Triggers Our Team Finds Most?

A head position

1 patient had waxing and waning symptoms for several years after a concussion. The worst were moments when thoughts just disappeared, movements froze partway, and the knees locked while walking. It looked random and it was frightening. Our team found that turning the head was the catalyst. With the head turned to the left, the patient could tap fingers and do simple math. Turned to the right, both stopped. Blood flow through the arteries told the same story: fine to the left, and a drop in supply to the right. Knowing that gave the problem a shape, and the patient did well once the work was aimed at it.

That's 1 case. How the neck can limit blood flow to the brain is on neck problems and the brain, and dizziness that follows neck position is on cervicogenic dizziness.

A meal

The ability to keep blood sugar steady can be impaired after a brain injury, in our team's experience, because the reflexes that manage it aren't working normally. A glucose check can come back fine while the person still crashes after carbohydrate-heavy meals. A large meal also pulls blood into the digestive tract and out of circulation for everything else. For someone already on the edge with blood flow to the brain, that's enough to bring symptoms on. The mechanism is measured in POTS and covered on why POTS is worse after eating.

Heat

Most people who feel worse in hot weather or a hot shower already know the link. The reason matters, because it turns avoidance into something that can be worked on. Heat pulls blood into the skin to shed warmth, on a set of vessels separate from the ones that hold blood pressure up. When the blood pressure reflexes are working normally, a temperature change has much less effect. Our team's order is to sort out those reflexes first, then build heat tolerance slowly, for example gentle early-morning sun with the legs in cool water. Heat intolerance covers the detail.

A busy environment

Cars, grocery stores, classrooms and bright rooms with a lot of movement bring symptoms on for many people, and it can feel as though everything makes them worse. In a case our team describes, a head injury had left a constant slow drift of the eyes that showed up in the dark, a sign that the brain's sense of where the head is had been thrown off. Every deliberate eye and head movement was being built on top of that error. Once the drift was resolved, the car, the store and the classroom all became easier.

Provoking symptoms with eye and head movement is a standard part of concussion testing. In 64 young patients tested about 5 days after a sport concussion, 61% had symptoms brought on by at least 1 item of a vestibular and eye movement screen (Mucha, 2014).

Why Are Symptoms Worse on Some Days Than Others?

In our team's view the triggers stack. A short night, a hot day, a big lunch and an afternoon in a busy store each take a share of the margin, and the last one gets the blame. Exertion counts too: a review found some evidence that the heart's autonomic control is altered during physical activity after a concussion, while noting the studies were small (Blake, 2016).

Our team suggests keeping a short log: what you ate, how you slept, the temperature, where you were and which way your head was when symptoms started. Patterns usually show up, and a pattern is something an exam can test.

What Should You Do About It?

Avoiding every trigger works for a while and shrinks your life. Our team's approach is to find which system the trigger is exposing and work on that system, so the trigger stops mattering. That means measuring: blood flow with the head in different positions, eye movements in the dark, heart rate and blood pressure with posture and effort. What that testing involves is on concussion testing: what to expect, and why symptoms last is on do concussions heal on their own.

Symptoms that are getting steadily worse, a new severe headache, repeated vomiting, weakness or confusion need a physician, and pupils different sizes after a head injury lists the signs that need an emergency department.

Concussion Symptoms That Come and Go: FAQ