Heart rate variability
of athletes across concussion recovery milestones: A preliminary study

Senthinathan A, Mainwaring L, Hutchison M. Clin J
Sport Med. 2017; 27(3):288-295

Take Home Message: Athletes
that sustained a concussion displayed altered heart rate variability measures
compared with controls, and those with a history of concussion had more
disturbances in heat rate variability measures.

Concussions can affect numerous
physiological processes including those in the cardiovascular system (via the
autonomic nervous system).
Medical professionals can measure heart rate variability as a noninvasive,
objective measure to assess the influence of concussions on the heart and to
assist with return-to-play decisions. However, heart rate variability, which
has been explored for severe brain injury, has been understudied with respect
to sport concussion. Therefore, the authors evaluated heart rate variability
among 11 athletes that sustained a concussion and 11 healthy sex- and sport-matched
controls. They tested the athletes at 3 phases during an athlete’s concussion recovery:
(1) within 1-week after injury (the symptomatic phase), (2) after resolution of
symptoms (progressing to exercise in return-to-play progression), and (3)
1-week after medical clearance to return to play. During each session,
participants completed the
Rivermead Post-Concussion Symptoms Questionnaire and physicians measured the participant’s heart rate
variability with heart rate monitors during three 5-minute intervals: twice
when the participant was sitting and once when standing, which provided a
measurement during a change in state and effort. The authors found no relationship
between heart rate variability measures and concussion symptoms nor days taken
to return to play. However, the authors found a relationship between concussion
history and physiological function of the heart where those with a greater
number of previous concussions had greater physiologic disturbances and increased
sympathetic and decreased parasympathetic activation while sitting. The authors
also detected that several measures of heart rate variability were different
between groups over time. Typically, the two groups were different during the
symptomatic phase (2-7 days post injury). However, the controls didn’t change
much over time but the athletes with a concussion had heart rate variability
changes that made their variability more like the control athletes by one week
after return to play.

authors found that an athlete with a concussion is likely to have altered heart
rate variability when compared with a control athlete. The authors also
suggested that heart rate variability was related to increased frequency of
previous concussions.  It is interesting
to note that such most of the heart rate variability findings were noted in the
sitting position, and not in the standing position. However, further
investigation is necessary to determine if this is still true after controlling
for concussion history, which was found to be associated with heart rate
variability. On the other hand, the authors also found a small change in heart
rate variability measures in the control group, which could be attributed to other
physiological and psychological stressors (exams, relationships, work). Future
studies should incorporate baseline heart rate variability testing, while also assessing
and accounting for other physiological and psychological stresses that could be
going on during a baseline testing session. At this time, medical professionals
should be aware of the impact of concussion and concussion history on the
heart, and continue to educate athletes on the risks concussions pose on
themselves if they do not report a possible concussion injury (e.g., heart rate
variability, greater risk of lower extremity injury).

Question for
Discussion: Do you monitor heart rate variability following injuries? Could you
implement heart rate monitors during preseason baseline testing? Would you
consider adding this to your concussion assessment and return to play protocol?

Written by: Jane McDevitt, PhD
by: Jeff Driban

Related Posts:

Senthinathan A, Mainwaring LM, & Hutchison M (2017). Heart Rate Variability of Athletes Across Concussion Recovery Milestones: A Preliminary Study. Clinical Journal of Sport Medicine, 27 (3), 288-295 PMID: 27379659