In a new study, Western researchers have shown just one 20-minute session of moderate intensity aerobic exercise can improve an athlete's executive function and concussion symptoms in the early stages of recovery.
Executive function is essential for everyday tasks, from remembering a grocery list to making strategic decisions in sports. When a basketball player closely guarded by an opponent holds back from shooting, opting to pass the ball to a teammate instead, they're tapping into the brain's inhibitory control - an important aspect of executive function. But a sports-related concussion can disrupt executive function, impacting on-field performance.
Matthew Heath (Kim McCready/Western Health Sciences)
"Executive function is an underlying feature of high-level cognitive control," said Matthew Heath, professor and faculty scholar in the School of Kinesiology at Western and senior author of the paper. "One of the most persistent symptoms or deficits associated with a sports-related concussion is an impairment in executive function, resulting in difficulties making quick on-field decisions."
Now, Western researchers have discovered a promising way to help athletes bounce back.
The findings, published Feb. 12 in the Journal of Sports Sciences, underscore the positive effects of aerobic exercise on a concussed athlete's executive function.
"When athletes with sports-related concussions engaged in aerobic exercise below their symptom threshold, we found their executive function, which is the ability to multitask, to plan things and to inhibit or withhold impulsive responses, improved," said Alma Rahimi, first author of the paper and a Schulich School of Medicine & Dentistry graduate with a master's in neuroscience.
Varsity athletes studied after injury
Researchers conducted the study with 16 Western varsity athletes in the early stages of concussion recovery, spanning three to 14 days post-injury. The athletes were compared to a control group of 16 athletes who had not experienced a concussion.
The concussed athletes first completed a task to assess their executive function, then exercised for 20 minutes at their sub-symptom threshold, identified by determining their heart rate at 80 per cent of where concussion symptoms began to worsen. After the exercise, participants repeated the executive function task.
Researchers tested athletes' executive function before and after exercising using a rapid eye test. (Kim McCready/Western Health Sciences)
Evaluating their performance pre- and post-exercise revealed the workout decreased the amount of time required for concussed athletes to complete the task, said Rahimi, who is now a clinical psychology master's and PhD student at the University of Toronto.
"We measured athletes' executive function before as well as after the exercise and found they had shorter reaction times, indicating that exercise improves executive function. The fact that a 20-minute bout of exercise could lead to improved cognition is very exciting."
In addition to improvements in executive function following exercise, the study also noted a reduction in the severity and frequency of concussion symptoms. When researchers followed up with study participants 24 hours later, they found symptoms such as headaches, nausea and dizziness also improved. These findings suggest executive function benefits are also closely tied to the alleviation of concussions symptoms, Heath said, which may be in part due to increased blood flow to the brain.
Accelerating concussion recovery through exercise
Understanding how the brain responds to a single session of exercise after a concussion is a major step forward in aiding the recovery of athletes with sports-related concussions. It also reinforces that the traditional approach of prescribing cognitive and physical rest should no longer be the standard.
Alma Rahimi (Submitted)
"Athletes don't have to seclude themselves in a dark room," said Rahimi. "They can walk, get on a bike or anything that allows them to increase their heart rate and activate their muscles, ensuring they don't further injure themselves or exacerbate their symptoms."
Identifying that threshold where athletes benefit from improved executive function without exacerbating their symptoms is key. This is where clinical kinesiologists can play a vital role, prescribing appropriate exercise intensity and duration tailored to an athlete's post-concussion recovery needs, Heath said.
"The evidence is clear that exercise, when prescribed appropriately, can help athletes and anyone with a concussion."
This is good news for athletes eager to return to training. But with a deeper understanding of the effects of sports-related concussions, it may also mean a longer recovery period before returning to play.
"Even when athletes are cleared for safe return to play, we have shown in previous studies their executive function in some cases is still impaired," said Heath, a researcher in the Faculty of Health Sciences. "This suggests they might not be entirely ready to go back to play."
In severe cases, the researchers found some athletes never fully recover from deficits in their executive function. Currently, there are limited guidelines available to support athletes dealing with these ongoing challenges.
That's why the researchers believe these findings are essential for advancing the understanding of sports-related concussions. This growing knowledge is expected to pave the way for more effective strategies to help athletes recover and return to peak performance.
"Concussion is such an unpredictable and individualized injury," said Rahimi.
"The future of the research is to understand if exercise improves cognition globally, or more specifically in one aspect. Our hope is for athletes who experience a sports-related concussion to get better faster - but also get better period."
