Neurological

Aerobic Exercise After Concussion In Adolescents: Is There A Neuroprotective Effect?

Exercise-induced symptom exacerbation in postconcussive patients is inversely associated with the percentage of maximum heart rate at the arterial carbon dioxide breakpoint (FETCO2), researchers found in a study published in Neurology. Post-concussive changes in cerebrovascular function during exercise can be a protective mechanism.

Progressive training aids recovery from concussions, but the intensity of training that is beneficial is difficult to determine because exercise can also make symptoms worse. Identifying the aspects of exercise that may increase the risk of symptoms getting worse would help neurologists advise patients on how best to exercise during their recovery.

Changes in vascular responses to exercise, particularly the effects of a change in arterial CO2, are likely.

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The aim of the study was to determine whether cardiopulmonary and cerebrovascular reactions during acute exercise in adolescents made symptoms worse.

40 patients (17.6 ± 2.2 years old; 55% women) who had suffered a sport-related concussion within the last 3 weeks and were symptomatic at rest, and 37 control persons (18.3 ± 2.4 years old; 62 % Women) with no previous year history of concussion enrolled in the study between September 2018 and February 2020. They completed modified YMCA branching exercise protocol exercises on a stationary bike.

Post-concussive patients completed exercise tests 12.5 ± 4.7 days and 12.5 ± 4.7 days after concussion. The tests were concluded either after an exacerbation of symptoms (n = 7 ≥30 visual-analog scale (VAS) mm) or after reaching 85% of the age-predicted maximum heart rate (HR). Participants after a concussion had significantly higher values ​​in the Post-Concussion Symptom Inventory (PCSI) compared to the control group.

The percentage of end-tidal CO2 (FETCO2), surrogate for arterial CO2, and the heart rate increased during the entire exercise, remained constant and decreased. Exercise intensity and heart rate were associated (R2> 0.75), except in 7 tests that did not show sufficient signal quality when recording the heart rate.

A higher heart rate at the FETCO2 breakpoint was associated with a smaller change in symptom burden on both visits.

The FETCO2 limit value influenced the exacerbation of symptoms regardless of the severity of symptoms at the start of the study.

In subjects with concussions, VAS at rest and the FETCO2 breakpoint resulted in 68% of the variation in exercise-induced symptom exacerbation (R2 = 0.65 [adjusted for number of variables]; FETCO2 β = -1.210 ± 0.517 [S.E.], P <.05).

The change in FETCO2 was related to the cerebral blood flow rate during exercise. In 73% of people, CO2 explained more than 25% of the changes in CBF during exercise.

Among postconcussive individuals, the researchers identified a moderate, statistically significant association between cerebrovascular responses to CO2 at rest and cerebrovascular responses to exercise-induced changes in FETCO2 (R2 = 0.13 P = 0.01).

Limitations of the study include generalizing to other age groups, excluding other concussion symptoms, inability to directly explain the influence of pressure changes on flow responses to exercise, and no assessment of brain hyperemia.

“Although it is not always advantageous or feasible to increase the training intensity, the intensity can be personalized based on the initial situation (cerebral vasoreactivity at rest and symptom burden),” say the researchers. “As a result, increasing the frequency of training combined with a personalized training intensity can provide the optimal training volume to improve post-concussion results. This is especially important because exercise and exertion can worsen concussion symptoms even if the symptoms are not visible at rest, and concussion-like symptoms are present in a large proportion of healthy people at rest. “

relation

Howell DR, Hunt DL, Aaron SE, et al. Association of hemodynamic and cerebrovascular responses to exercise with severity of symptoms in adolescents and young adults with concussion. Neurol. Published online October 11, 2021. doi: 10.1212 / WNL.0000000000012929

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