John Leddy, MD, on Returning to Exercise After Concussion


In this podcast, Dr Leddy discusses important considerations for returning to exercise post-concussion, explains common pitfalls in the diagnosis and treatment of sports-related concussion, and addresses treating acute sports-related concussion via early testing and sub-symptom threshold aerobic exercise. Read the transcript here. He recently gave a talk on this topic at the American Academy of Neurology 2020 Sports Concussion Virtual Conference.

Additional Resource:

  • Hainline BW, Leddy JJ. Return to activity and the role of exercise post COVID-19. Talk presented at: American Academy of Neurology 2020 Sports Concussion Virtual Conference; July 31, 2020; Virtual.

John J. Leddy, MD, is the medical director of the University at Buffalo Concussion Management Clinic, and clinical professor in the Department of Orthopedics at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences in New York.



Christina Vogt: Hello everyone, and welcome back to another podcast. I’m Christina Vogt, associate editor of the Consultant360 Specialty Network. Today, I’m joined by Dr John Leddy, who is the medical director of the University at Buffalo Concussion Management Clinic, and clinical professor in the Department of Orthopedics at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences. Thank you for joining me today, Dr Leddy. So first, what are some recent diagnostic and treatment advances that have been made when it comes to the return to activity and exercise after concussion?

Dr Leddy: The most recent treatment advance was a randomized trial we published last year in JAMA Pediatrics, where we showed that high school athletes who were an average age of 15 years old who were seen within 5 days of their concussion–they recovered faster after their concussion when they were randomly assigned to a sub-symptom threshold aerobic exercise routine vs a placebo-like stretching routine.

We enrolled over 100 subjects, half of which about were randomly assigned to the exercise, and half of which were assigned to the stretching program where you followed their symptoms every day for a month. And every week, they came in to have what was called the Buffalo Concussion Treadmill Test, which is a treadmill test that is used to identify the point at which someone has exacerbation of concussion symptoms during exercise, and each week, the subjects got a new exercise prescription, whether that was aerobic exercise at a particular heart rate or new stretching program to do, and then we followed them until they recovered. Recovery was defined as being back to baseline symptoms, having a normal neurologic physical examination and normal ability to exercise on the treadmill without symptom exacerbation. And, we found that both boys and girls responded faster to exercise, they recovered on average 4 days faster than if they had the stretching routine, there were no adverse events or side effects, so it was safe, and only a small percentage of them went on to have a delayed recovery beyond a month in the aerobic exercise group. It was 2 out of 53. I believe, in the stretching group, it was 7 out of 61 or 2, and this was not different between the groups, but it is much better than if you don't do anything for an adolescent athlete after concussion, if you tell the athlete to go home and rest until his or her symptoms go away. The best research in the field shows that, after a month, 35 to 40% of them will be symptomatic, and in our study, there were only 5% in the aerobic exercise group and 15% in the stretching group that went on to complete recovery.

The other nice aspect of the study was that half the subjects were female, and the females responded just as well as the males did to this approach. There's some studies in the concussion literature, if you look at recovery of adolescents after concussion when they're told to rest and not do anything, females take longer to recover than males, but with this approach they recovered in the same time.

Christina Vogt: What are some common pitfalls when it comes to the diagnosis and treatment of sports-related concussion, and how can they be avoided?

Dr Leddy: Some of the pitfalls are when doctors in their office are seeing patients who've had a concussion, they typically are seeing them days or weeks later, and they're not at the event that caused the concussion. So, it can be a little hard sometimes to know that a concussion did indeed occur. The symptoms after these injuries are pretty nonspecific and can sometimes be produced by someone, say, with a neck injury or a peripheral vestibular injury without a concussion. So, that's one of the problems treating clinicians run into when they're seeing somebody not at the time of the injury or the next day, let's say.

And so, one of the things that we found was that, using this principle of exercise intolerance, you can help to sort that out. And what I mean by that is, one of the physiological stressors that reliably increases symptoms after a concussion is doing too much exercise before you're recovered, but you can use that in a controlled way to help make the diagnosis. That is, if it's a week later, and you're not entirely sure the symptoms are from concussion or another problem, you could put or have an associate of yours–trainer, therapist, sports medicine doc, and exercise physiologist–just put your patient on a bike or treadmill and take up the exercise intensity gradually and see if the concussion symptoms are brought on or exacerbated by controlled exercise, and if they are, you can be pretty sure that, in fact, it was a brain concussion at the time, and the patient has not recovered yet. If, however, they have good exercise tolerance, so that they can pedal on the bike or run on the treadmill, and so they stopped because of exhaustion because their heart rate has gotten up their maximum, then you can be pretty sure that, in fact, it was not a concussion, and the source of the symptoms is coming from someplace else. Now, it might be someplace else from the brain like an ocular motor problem or, again, a vestibular injury. That's really separate from concussion, or it might be a neck injury or an exacerbation of a prior problem, like a migraine headache or something like that. So, we can use this principle of exercise tolerance to help in the diagnostic approach to concussions sometimes.

The other pitfall is related to the first principle I discussed, is that it's really not good practice anymore to tell patients to go home and do nothing for days or weeks–no physical activity, not going to school, no significant cognitive activity, and just kind of rest until the symptoms completely go away, because we know now that that approach in fact, doesn't work, especially with athletes, especially with middle school, high school, college athletes–that it's much better to, after a few days of relative rest and when the symptoms are stabilizing, to try to get them activated earlier on than we did in the past–that is, to start to get them moving physically and doing cognitive activities, but in a controlled, measured way and identifying their individual symptom exacerbation thresholds for those types of activities, and then resting from that, and then working below them for every day after that, and then increasing their threshold, and pushing it a little bit to get them back into their activities faster, and to know that mild symptom exacerbation after concussion is, in fact, not dangerous and doesn't delay recovery. It's not causing brain damage. And in fact, it may be necessary to enhance recovery in these patients.

Christina Vogt: Could you discuss the treatment of acute sports-related concussion using early testing and using sub-symptom threshold aerobic exercise?

Dr Leddy: What we do is, typically, we take an athlete who's been injured a few days or week before and who’s still having symptoms. We do a neurological exam to make sure there are no red flags or obviously any focal deficits that would require brain imaging. The vast majority of concussion patients don't have any red flags. Now, they may have rather subtle oculomotor and vestibular deficits on exam, but these are not indications for imaging.

And then, we have to have some way to generally assess their exercise tolerance. We have the Buffalo Concussion Treadmill Test, and we have the Buffalo Concussion Bike Test that we've published on, and that's available in the literature. And, what we try to do is identify everybody's individual symptom exacerbation threshold point during the exercise test, and we take that heart rate where they express their symptoms, and we take 90% of that heart rate and give that as a training dose to use in association with some sort of heart rate monitor so they know what their pulse is, and we ask them to do aerobic exercise, generally on a stationary bike first, and then a treadmill if they’re tolerating the bike and exercise at that target heart rate for as long as it takes to bring their symptoms up again. So, that might be 10 minutes and might be 20 or 30 minutes. We try to get them to do it for at least 20 minutes a day, if possible, but they can stop before that or after that, depending if their symptoms go up by 2 or more points from their pre-exercise baseline. We explain to them how to do that–just identify how you're feeling, is 2 out of 10, a 4 out of 10? And then once your symptoms go up by more than 2 points during your exercise bout, then you should stop, or you can stop in 20 to 30 minutes, but the idea is to do that every day.

And then as they're feeling better, then increase their target heart rate, either 5 or 10 beats per minute depending on how they're doing, depending what kind of athlete they are, until they can exercise basically to 80% or more of their age-predicted maximum for 20 minutes or more without symptoms getting exacerbated for a few days in a row. And we, at that point, declare them cerebrovascularly and cardiovascularly, physiologically recovered, and they've completed the aerobic training part of the return-to-play process, and then they can then go right into sports-specific training, which is stage 3 of the return-to-play process for getting athletes back to contact sports. They have to go through several stages, but after doing this aerobic exercise training, they've already done stages 1 and 2, they can go right to stage 3.

And again, not everybody has a treadmill or a bike, and they can't do the concussion treadmill test, but you can have an athlete even try to identify his or her own threshold on a piece of exercise equipment they might have at home or in our training room. Maybe work with their athletic trainer or physical therapist to do this. It's very good for athletes. It gets them engaged in their recovery. They’re goal-oriented people. They're accustomed to exercising, and after concussion, they don't feel good for a while, and then not exercising–so, that can even exacerbate their concussion symptoms. So, we try to get them to do something in a controlled, measured way, talk to them about identifying their threshold, and then staying below it, but getting them engaged in their recovery has generally been very successful.

Christina Vogt: What will be some key areas of future research going forward?

Dr Leddy: Well, one is we don't know how much exercise after concussion is sufficient. We don't really have the doses established. Is every day necessary? Is it 20 minutes or every other day, or 3 days a week at half an hour? So that's one question.

How early can you do this after concussion? In fact, we published that–we've done it as early as 2 days after the injury in high school athletes, and we certainly do that in college. We do it within a couple of days with the injury once their symptoms have stabilized. So, you can do this in the first 2 to 3 days, provided the resting symptoms are not 7 out of 10 or above. We don't want to do a test when somebody's very symptomatic at rest, but generally after a day or 2 if they've gotten down below that level, and you can do the test safely in those patients and do the exercise prescription safely in most patients.

Another big thing in the concussion world is, does clinical recovery mean physiological recovery? That is, when patients appear to be recovered because they say their symptoms are down, they look like they can exercise, okay, their physical examination is normalized, is the brain still at risk for repeat injury, or is the brain really truly physiologically recovered, and how do you measure that? Is that with a functional MRI or DTI for potential imaging tests? Is that a test of cerebral blood flow? Is it some sort of serum biomarker? And so, more and more research has shown that if you do some of these rather sophisticated and subtle physiological tests, they can appear to be abnormal still in patients who otherwise appear to be clinically recovered. So, the question is, what does that mean? How long does that last? What does that mean in terms of vulnerability for repeat injury or potentially long-term problems after multiple concussions? Nobody really knows that, and that's a fertile area for further research. The other big area is sex differences. How are females the same as males? But also, how are they different in terms of their physiological recovery? Does it relate to the phase of the menstrual cycle where they were injured, hormonal influences, things like that?

Now, the big area will be the genetics of concussion: Who's more susceptible based upon a potential genetic predisposition to having delayed recovery, for example.

Christina Vogt: And lastly what key takeaways do you want to leave with neurologists and related health care providers who treat concussion?

Dr Leddy: I'd like neurologists to know about the idea of exercise intolerance being a physiological sign of concussion that you can use in helping to establish the diagnosis, but also in helping to get your patients more active earlier on in the process, because it seems to help them recover faster and also, I think, will prevent some of them from going on to this delayed recovery, and it's really those patients that have the most problem with school and teams and socialization, etc–the patients that are taking a month or more to recover. They can have a really prolonged course after this sometimes, and I think

by not cocooning them, not putting them at rest, in the dark, and not doing anything to exacerbate symptoms at all is not is no longer the way to go. You want to get them active in a controlled way earlier on in a measured way. Tell them to pay attention to symptom exacerbation, but don't scare them that that's going to hurt their brain or delay their recovery, because all the studies that have looked at that have shown that, in fact, does not do that. So, don't be afraid to be more proactive in getting patients active earlier on after concussion, and most of these people don't need any form of neuroimaging unless some cranial nerve deficit appears, or the headaches are getting worse, or their symptoms are very prolonged, and again changing, not getting better, because the vast majority of these patients have normal structural MRI scans.

The other thing I'll ask neurologists to think about is examining the cervical spine. These are cervical strains and sprains etc. Proprioceptive deficits are very common after concussion injury, and some research has shown that that isolated neck injuries can actually mimic the symptoms of a concussion or add to them. So, you can have both injuries at the same time. So, if you don't treat the neck, then the recovery will be prolonged. So, do a good physical examination that includes not only cranial nerves and your basic neurological examination, but also looking at the cervical spine because a good physical therapist can help these patients recover. And look for subtle oculomotor and vestibular deficits, because this is very, very common after concussion, and if those don't go away in the first few weeks, that's a definite risk factor for this delayed recovery phenotype. And there are good interventions for that, that you can get patients into– vestibular rehabilitation, for example, if they're not improving over 2 to 3 weeks, and help them recover much faster than if you just sort of wait for that to go away naturally.

Christina Vogt: Thanks again for joining me today, Dr Leddy.