Influence of Aerobic Exercise Volume on Postconcussion Symptoms

Abstract

Background: Aerobic exercise has emerged as a useful treatment to improve outcomes among individuals who experience a concussion. However, compliance with exercise recommendations and the effect of exercise volume on symptom recovery require further investigation. Purpose: To examine (1) if an 8-week aerobic exercise prescription, provided within 2 weeks of concussion, affects symptom severity or exercise volume; (2) whether prescription adherence, rather than randomized group assignment, reflects the actual effect of aerobic exercise in postconcussion recovery; and (3) the optimal volume of exercise associated with symptom resolution after 1 month of study. Study Design: Cohort study; Level of evidence, 2. Methods: Individuals randomized to an exercise intervention (n = 17; mean age, 17.2 ± 2.0 years; 41% female; initially tested a mean of 11.3 ± 2.8 days after injury) or standard of care (n = 20; mean age, 16.8 ± 2.2 years; 50% female; initially tested a mean of 10.7 ± 3.2 days after injury) completed an aerobic exercise test within 14 days of injury. They returned for assessments 1 month and 2 months after the initial visit. The aerobic exercise group was instructed to exercise 5 d/wk, 20 min/d (100 min/wk), at a target heart rate based on an exercise test at the initial visit. Participants reported their exercise volume each week over the 8-week study period and reported symptoms at each study visit (initial, 1 month, 2 months). Because of low compliance in both groups, there was no difference in the volume of exercise between the 2 groups. Results: There were no significant symptom severity differences between the intervention and standard-of-care groups at the initial (median Post-Concussion Symptom Inventory, 15 [interquartile range = 10, 42] vs 20 [11, 35.5]; P = .26), 1-month (4 [0, 28] vs 5.5 [0.5, 21.5]; P = .96), or 2-month (6.5 [0, 27.5] vs 0 [0, 4]; P = .11) study visits. Exercise volume was similar between groups (median, 115 [54, 225] vs 88 [28, 230] min/wk for exercise intervention vs standard of care; P = .52). Regardless of group, those who exercised <100 min/wk reported significantly higher symptom severity at the 1-month evaluation compared with those who exercised ≥100 min/wk (median, 1.5 [0, 7.5] vs 12 [4, 28]; P = .03). Exercising ≥160 min/wk successfully discriminated between those with and those without symptoms 1 month after study commencement (classification accuracy, 81%; sensitivity, 90%; specificity, 78%). Conclusion: Greater exercise volume was associated with lower symptom burden after 1 month of study, and an exercise volume >160 min/wk in the first month of the study was the threshold associated with symptom resolution after the first month of the study. Because our observation on the association between exercise volume and symptom level is a retrospective and secondary outcome, it is possible that participants who were feeling better were more likely to exercise more, rather than the exercise itself driving the reduction in symptom severity.

More Physical Activity after Concussion Is Associated with Faster Return to Play among Adolescents

“…The group who received RTP clearance ≥28 days post-injury also exercised for fewer total minutes per week than those who recovered within the first 28 days of concussion. As with our step count findings, these are interesting association-level data that suggest a link between exercise volume and concussion recovery, aligning with past work [18]. However, we did not observe significant between-group differences for the average amount of time spent exercising or exercise intensity per session, suggesting that exercise frequency may be an important element of exercise prescription during concussion recovery.…”

“…Furthermore, while it is plausible that more exercise after concussion contributed to a faster recovery, it is also just as likely that those who were feeling better early on after injury were more likely to engage in more consistent exercise and physical activity. Despite this, our findings build on past work that used self-reported exercise volume suggesting further that aerobic exercise is associated with faster recovery after concussion [14,18].…”

“…Participants responded to 21 items by rating each symptom (e.g., headache, nausea, balance problems) on a 7-point scale indicating severity from 0 (Not a Problem) to 6 (Severe Problem). We calculated total PCSI score as the sum of all responses where the higher the value, the more symptomatic the participant [18,19].…”

An 8-Week Neuromuscular Training Program After Concussion Reduces 1-Year Subsequent Injury Risk: A Randomized Clinical Trial

“…44 In contrast, adolescents with concussion seemingly adhere poorly to physician recommendations 40 or aerobic exercise interventions. 14 Thus, incorporating NMT elements into RTP protocols may augment existing rehabilitation approaches, which have largely focused on aerobic exercise. 26,42…”

Postconcussion Exercise Volume Associations With Depression, Anxiety, and Dizziness Symptoms, and Postural Stability: Preliminary Findings

“…This study is a secondary analysis of a randomized clinical trial comparing an aerobic exercise intervention within 2 weeks (individualized target heart rate-based exercise recommendation) of a concussion with standard of care (symptom-limited physical activity). 12 Participants were not blinded to group assignment, as they had to know the exercise volume that they were assigned to meet recommended exercise guidelines. Given our previous finding that the optimal exercise volume to distinguish concussion symptom resolution after 1 month of study was 160 min/wk or more 12 and optimal exercise recommendations for cardiovascular health are 150 min/wk or more, 14 we grouped participants on the basis of whether they reported aerobic exercise 150 min/ wk or more (high exercise volume group) versus less than 150 minutes (low exercise volume group).…”