Common advice for people with concussions is to avoid exercise and rest in the days and weeks after the injury. But that isn’t based on current medical advice. In fact, total rest beyond a day, and even relative rest beyond a few days, can prolong symptoms. Elizabeth Sandel, MD, author of Shaken Brain: The Science, Care, and Treatment of Concussion, sets the record straight.
In the nineteenth and twentieth centuries, doctors recommended rest for anyone with a concussion. Sometimes that included bedrest or sedentary activities within the home. In the twenty-first century, the concussion literature still uses varying definitions of rest. A practical definition of physical rest makes a distinction between the absence of athletic activities on the one hand, and daily activities that require exertion on the other. Sitting out football practice doesn’t mean you can’t go grocery shopping, mow the lawn, or lift free weights at the gym. Cognitive rest, on the other hand, refers to minimizing high-concentration activities that exacerbate concussion symptoms, such as computer use, reading and writing, and watching television. For people with concussion symptoms, these activities may be challenges at home or school, in the community, or at work.
After a concussion, biochemical events alter cerebral blood flow, cellular metabolism, and cellular structures during a period of vulnerability. This vulnerable period is the basis for current guidelines requiring removal from play and protection from another concussion or second impact syndrome. Re-exposing the developing brains of children, adolescents, and young adults during this vulnerable period can cause further damage. Return-to- play decisions are a complicated matter because imaging studies suggest that using symptoms to determine return to risky activities is itself risky because brain abnormalities persist after symptoms resolve.
Very intense exercise shortly following an injury may cause harm because exercise compels higher metabolic demands on the body. Cerebral blood flow and glucose metabolism differ in children and adolescents. The reality is that scientists don’t yet have complete answers about when a person who has had a brain injury can safely resume exercise, or what kinds of exercise are safe. But some clinical research suggests that activity, even light exercise, might be the best medicine after a concussion. Total rest beyond a day, and even relative rest beyond a few days, can prolong symptoms.
The brain may not respond well to inactivity. Low-level exercise may actually hasten recovery or even improve it. We know that exercise can effectively treat anxiety, depression, and mood regulation, and that bedrest can contribute to poorer recoveries and disability after injury or illness. We also know from studies of more severe TBIs that exercise promotes brain-derived neurotrophic factor (BDNF), which stimulates the growth of neural stem cells and new synapses, a process called neurogenesis.
Differing statements by the authors of the International Conferences’ Consensus Statements in the last two conferences — Zurich in 2013 and Berlin in 2017 — reflect a shift in thinking among clinicians about post-concussion rest. The Zurich group recommended physical and cognitive rest until symptoms resolve. The Berlin group’s statement shows the shift: “After a brief period of initial rest (24–48 hours), symptom-limited activity can be begun while staying below a cognitive and physical exacerbation threshold.” This newer recommendation limits the period of rest and encourages earlier activity. In 2018, the American Academy of Pediatrics also revised its 2010 mild TBI guideline, changing the period of rest to no more than two to three days. Unfortunately, for some individuals, especially young people, 24 to 48 hours may be too short a period for enough symptom resolution. The science of concussion is still primarily based on consensus rather than solid research evidence, and this serves as another example of the imperfect science of medicine.
After a concussion, patients may need to take some time away from work or school to decrease stressful contributions to their symptoms, but they should continue activities outside the home. A return to normal activities (including work or school) should occur as soon as a patient can tolerate them. When a person returns to mental or physical activity after a concussion, the key is to start slowly. An assistive device such as a cane or a shower chair can aid balance and coordination in the days, weeks, or months after a concussion, especially for older people. Certain activities, such as aerobic exercise, may make symptoms worse, but frequent breaks or a reduction in the intensity of the activity can help. A patient may need to minimize time reading or looking at a screen if these activities bring on or intensify symptoms such as headaches.