Aerobic Exercise: Benefits Following Brain Injury

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Following a traumatic brain injury (TBI), aerobic exercise promotes cardiovascular fitness, cognitive recovery, and reductions in mood disorders.¹

Cardiorespiratory Fitness

Physical inactivity, increased sedentary behavior, and greater perceived fatigue are commonly reported following TBI.² Chin et al³ enrolled a small sample of adults with nonpenetrating TBI in a 12-week aerobic training program to assess the impact of vigorous exercise on cardiorespiratory fitness. Participants (N=10) completed a cardiopulmonary exercise test measuring gas exchange during exercise (ie, oxygen consumption and carbon dioxide output), and completed the Fatigue Severity Scale (FSS) at baseline and following the 12-week exercise training. Participants engaged in supervised exercise training on a treadmill for 30 minutes, 3 times per week at a vigorous intensity, maintaining 70% to 80% of heart rate reserve. At the training completion, statistically significant changes were noted in peak oxygen consumption, time to fatigue, and peak work rate. Participants also reported considerably lower fatigue as evidenced by statistically significant decreases in FSS composite scores.

Cognition

Exercise may promote cognitive recovery via mechanisms such as increasing neural repair and neuroplasticity, modulating neurotransmitter systems, and decreasing neuroinflammation.1In a systematic review of controlled clinical trials and randomized controlled trails with adults with neurologic disorders, McDowell et al reported that aerobic exercise improved cognition, particularly attention and cognitive flexibility in adults with TBI.⁴

Chin et al enrolled a small volunteer sample of ambulatory adults with chronic, nonpenetrating TBI into a 12-week aerobic exercise training program to determine the effect of exercise on cognitive performance.⁵ Participants (N = 7) received 30 minutes of supervised vigorous aerobic exercise training on a treadmill, 3 times per week. Cognitive function was assessed at baseline prior to the beginning of aerobic exercise training, and at the completion of the 12-week intervention. Cognitive function was assessed using the Trail Making Test, parts A and B, and the Repeatable Battery for the Assessment of Neuropsychological Status.

Mood

About 50% of individuals with TBI report clinically significant levels of anxiety and depression within the first year of injury.⁶

Weinstein et al⁷ enrolled 12 ambulatory adults with nonpenetrating TBI into a 12-week aerobic exercise training program to determine the effect of exercise on mood. Changes in mood before and after exercise were measured using the Profile of Mood Status—Short Form (POMS-SF), obtained at baseline (week 1), week 4, week 8, and week 12 (conclusion). The POMS-SF scoring generates a total mood disturbance (TMD) score, with higher scores indicating a more negative mood state. Participants were engaged in 30 minutes of intensive aerobic exercise, 3 times per week. Participants also engaged in a 5- to 10-minute warm-up and cooldown period. The exercise sessions were maintained at 70% to 80% of the participants’ heart rate reserve, which was continuously monitored during exercise. Target range was maintained by adjusting the speed and/or grade of the treadmill. Analyses showed improvement in mood as evidenced by significantly lower TMD scores between weeks 1 and 12. Improvements in mood were detectable after a single exercise bout in week 1. The greatest changes in POMS-SF scores were noted in the Fatigue-Inertia and the Anger-Hostility subscales.

In a pilot study to determine the feasibility of aerobic exercise for lowering depressive symptoms, Schwandt et al enrolled a small sample (N = 4) of community dwelling adults with TBI and residual physical impairments in a 12-week supervised aerobic exercise program.⁸ The primary outcome measure was the Hamilton Depression Rating Scale (HAMD), administered at baseline, midpoint, and 12 weeks following the conclusion. Additional measures obtained at baseline and at 12 weeks included assessment of functional aerobic capacity (heart rate above 70% of age-predicted maximum), perceived exertion as assessed by the Borg Rating of Perceived Exertion scale, the Rosenberg Self-Esteem Scale, and frequency of attendance. The intervention consisted of a warm-up (stretching or below target heart rate aerobic activity), 30 minutes of intensive aerobic exercise (intensity determined by a score of 5 to 6 on the Borg scale and a heart rate of 60% to 75% of age-predicted maximum), and a 10-minute cooldown. The intervention was delivered 3 times per week for 12 weeks. Participants worked with a research physical therapist to choose from a cycle, treadmill, or recumbent step machine to reach aerobic thresholds. After the 12-week intervention, HAMD scores decreased from the moderate-to-severe and severe levels of depression at baseline, to mild-to-moderate level or no symptoms at program completion. Additionally, heart rate was lower at post intervention, Borg scores were lower indicating less perceived effort, and self-esteem improved as evidenced by higher Rosenberg Self-Esteem Scale scores.

Concluding Thoughts

Aerobic exercise is associated with improved outcomes following TBI, not only in cardiovascular fitness but also in cognitive performance and mood disorders. However, many studies are proof-of-concept, pilot, or pre-post observational studies with small sample sizes, and have numerous methodological limitations. Well-designed randomized controlled trials are needed to test the efficacy of aerobic exercise and rehabilitation outcomes.

Dr Seale is the regional director of clinical services at the Centre for Neuro Skills, which operates post-acute brain injury rehabilitation programs in California and Texas. He is licensed in Texas as a chemical dependency counselor and psychological associate with independent practice. He also holds a clinical appointment at the University of Texas Medical Branch (UTMB) in Galveston in the Department of Rehabilitation Sciences.

References

1. Zang Y, Huang Z, Xia H, et al. The benefits of exercise for outcome improvement following traumatic brain injury: evidence, pitfalls and future perspectives. Exp Neurol. 2022;349:113958.

2. Driver S, Ede A, Dodd Z, et al. What barriers to physical activity do individuals with a recent brain injury face? Disabil Health J. 2012;5(2):117-125.

3. Chin LMK, Chan L, Woolstenhulme JG, et al. Improved cardiorespiratory fitness with aerobic exercise training in individuals with traumatic brain injury. J Head Trauma Rehabil. 2015;30(6):382-390.

4. McDonnell MN, Smith AE, Mackintosh SF. Aerobic exercise to improve cognitive function in adults with neurologic disorders: a systematic review. Arch Phys Med Rehabil. 2011;92(7):1044-1052.

5. Chin LM, Keyser RE, Dsurney J, Chan L. Improved cognitive performance following aerobic exercise training in people with traumatic brain injury. Arch Phys Med Rehabil. 2015;96(4):754-759.

6. Masel BE, DeWitt DS. Traumatic brain injury: a disease process, not an event. J Neurotrauma. 2010;27(8):1529-1540.

7. Weinstein AA, Chin LKM, Collins J, et al. Effect of aerobic exercise training on mood in people with traumatic brain injury: a pilot study. J Head Trauma Rehabil. 2017;32(3):E49-E56.

8. Schwandt M, Harris JE, Thomas S, et al. Feasibility and effect of aerobic exercise for lowering depressive symptoms among individuals with traumatic brain injury: a pilot study. J Head Trauma Rehabil. 2012;27(2):99-103.