INTRODUCTION: Submaximal aerobic exercise is the first step in the return-to-sport (RTS) protocol after sports-related concussion (SRC) and appears to be effective in speeding up recovery. How exercise during RTS is related to cardiac dysautonomia, a prominent and often persistent feature of SRC, remains to be elucidated. The aim of this study was to explore measures of the cardiac autonomic nervous system (cANS) in response to submaximal exercise in concussed athletes during RTS. METHODS: Thirty athletes participated in this study. 15 SRC athletes (age: 24 ± 5, BMI: 24 ± 2) were examined during RTS (days after concussion: 2-140, number of symptoms: 1-19). SRC athletes were compared to 15 matched controls (age: 25 ± 5, BMI: 24 ± 3). All athletes performed a progressive ergometer exercise protocol until reaching 70% of their age calculated maximal heart rate (HR). cANS data were collected pre and post (±10 minutes) exercise in supine position for 5 minutes using a wrist sensor (PPG). Mean HR (mHR) and the root mean square of successive differences of RR intervals (RMSSD) were analyzed. Subjective stress levels were documented pre and post exercise using the short recovery and stress scale. Wilcoxon Signed Rank Tests were used to explore statistical significance for differences between groups (concussed vs. controls) and time (pre vs. post exercise). RESULTS: mHR increased significantly from pre to post exercise in the SRC group (median (Mdn) = 59.34 bpm, interquartile range (IQR) = 15.54 to Mdn = 66.38 bpm, IQR = 13.11, Z = - 3.41, p < 0.001, r = -0.622) as well as in the control group (Mdn = 58.22 bpm, IQR = 11.75 to Mdn = 66.58 bpm, IQR = 15.42, Z = -3.41, p < 0.001, r = -0.622). RMSSD decreased significantly from pre to post exercise only in the SRC group (Mdn = 65.00 ms, IQR = 73.72 to Mdn = 46.68 ms, IQR = 27.48, Z = -2.73, p = 0.006, r = -0.497). The submaximal exercise parameters did not differ significantly between groups in watts achieved (Mdn = 2.02 vs. 2.17 watts/kg) or duration (Mdn = 14 vs. 14 min) of exercise. Subjective stress significantly increased for the control athletes from pre (Mdn = 3, IQR = 3) to post exercise (Mdn = 2, IQR = 4, p= 0.036, r = -0.383). CONCLUSION: Despite similar performance parameters during a submaximal exercise test, SRC athletes revealed a significant reduction in RMSSD 10 min post exercise when compared to controls, possibly indicating an altered cardiac parasympathetic recovery after submaximal aerobic exercise. High inter- and intraindividual variability of ANS parameters, the low sample size and broad range of days post injury need to be considered when interpreting these results.
© Copyright 2022 27th Annual Congress of the European College of Sport Science (ECSS), Sevilla, 30. Aug - 2. Sep 2022. Julkaistu Tekijä Faculty of Sport Science - Universidad Pablo de Olavide. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator