Background: The prevalence of autonomic dysfunction in cancer survivors requires further investigation. As support for high intensity exercise for this population increases, the need to assess exercise readiness for physiological adaptations arises. Purpose: To examine the effect of exercise intensity on acute recovery of the cardiac autonomic nervous system (ANS). Method: The randomised crossover design included 12 primary cancer diagnosis participants (age mean (SD): 58.58 (12.05) yrs, male=3). All completed treatment within the last two years. A moderate (50% VO2peak) and high (80% VO2peak) intensity cycling session was completed. Time and frequency heart rate variability (HRV) domains were recorded before exercise, during recovery up to 30min and at 24 and 48h post-exercise. An analysis of covariance (two-way ANCOVA) with Sidak’s post-hoc testing was performed to compare HRV recovery over time in response to the two intensities. Age, weight, BMI, VO2peak and date of treatment were covariates. Significance was set at p<0.05. Results: There were significant interaction effects between the recovery from moderate versus high-intensity exercise for heart rate (p<0.0001), R-R intervals (p=0.005), Log(Ln)RMSSD (p=0017), LnSDNN (p=0.0013), LnLF (p=0.0172), LnHF (p=0.0054), LnVLF (p=0.0053), and total power (p=0.0003). The major findings were 1) HRV returned to pre-exercise levels by 24h for both intensities, 2) cardiac parasympathetic activity (LnRMSSD, LnSDNN, LnHF) remained significantly lower 30min post high intensity, 3) parasympathetic decline and disturbance to the heart’s intrinsic rhythm were most significant at 10min, and 4) there was a negative effect of age and weight on HRV. Conclusion: Exercise intensity influenced acute and intermediate cardiac ANS recovery. Analysis of HRV in cancer survivors is a potentially useful tool in clinical practice. We recommend monitoring HRV before exercise and across recovery to ensure appropriate exercise prescription.
|Number of pages||1|
|Publication status||Published - 2018|
|Event||Research to Practice: Exercise & Sports Science Australia’s (ESSA2018) - Brisbane Convention Exhibition Centre, Brisbane, Australia|
Duration: 27 Mar 2018 → 29 Mar 2018
|Conference||Research to Practice|
|Period||27/03/18 → 29/03/18|