Relationship between Heart Rate Variability and Functional Fitness in Breast Cancer Survivors: A Cross-Sectional Study

Heart rate variability as an indicator of the beneficial effects of Qigong and mindfulness training on the mind-body well-being of cancer survivors

BACKGROUND

Cancer-related fatigue (CRF) and fear of recurrence (FOR) are frequently experienced by cancer patients. This study aimed to improve cancer survivors' CRF, FOR, quality of life (QOL), and heart rate variability (HRV) through Qigong and mindfulness interventions.

METHODS

A quasi-experimental design was adopted, and 125 cancer survivors were recruited using snowball sampling. The participants were assigned to 1 of 3 groups (Qigong, mindfulness, and control) based on their needs and preferences. All groups received 4 h of nutrition education at the pretest (T0). CRF, FOR, and QOL questionnaires and HRV parameters were used as the measurement tools. Data were collected at the pretest (T0), posttest (T1), and follow-up (T2).

RESULTS

Qigong had a better effect on improving CRF (ΔT1-T0 = - 0.108, ΔT2-T1 = - 0.008) and FOR (ΔT1-T0 = - 0.069, ΔT2-T1 = - 0.150) in the long term, while mindfulness improved QOL (ΔT1-T0 = 0.096, ΔT2-T1 = 0.013) better in the long term. Both Qigong and mindfulness had a short-term effect in improving SDNN (Q: ΔT1-T0 = 1.584; M: ΔT1-T0 = 6.979) and TP (Q: ΔT1-T0 = 41.601; M: ΔT1-T0 = 205.407), but the improvement in LF (Q: ΔT2-T1 = - 20.110; M: ΔT2-T1 = - 47.800) was better in the long term.

CONCLUSION

HRV evaluation showed that Qigong and the mindfulness interventions had short-term effects in significantly improving overall physical and mental health, self-emotional regulation, and QOL and relieving fatigue and autonomic dysfunction. HRV may serve as an observational indicator of interventions to improve physical and mental health. The consistent practice of mind-body interventions is the primary means of optimizing overall health and well-being.

The Comparative Effect of Reduced Mindfulness-Based Stress on Heart Rate Variability among Patients with Breast Cancer

Heart rate variability (HRV) is a powerful tool for observing interactions between the sympathetic and parasympathetic nervous systems. This study evaluated HRV during a mindfulness-based stress reduction (MBSR) program among women with breast cancer after receiving treatment. A quasi-experimental, nonrandomized design was used. Patients were allocated to usual care (n = 25) and MBSR (n = 25) groups. HRV was measured using recognized methods to assess the autonomic nervous system. Two-way ANOVA and t-tests were used to examine HRV changes between and within groups, respectively. A significant interaction effect of time with group was observed on heart rate (F (1, 96) = 4.92, p = 0.029, η2 = 0.049). A significant difference was also observed within the MBSR group preintervention and postintervention with regard to heart rate (t (24) = −3.80, p = 0.001), standard deviation of the RR interval (t (24) = 5.40, p < 0.001), root-mean-square difference in the RR interval (t (24) = 2.23, p = 0.035), and high-frequency power (t (24) = 7.73, p < 0.001). Large effect sizes for heart rate and SDNN of 0.94 and 0.85, respectively, were observed between the MBSR and usual care groups. This study provides preliminary evidence that an MBSR program may be clinically useful for facilitating parasympathetic activity associated with feelings of relaxation in treated breast cancer survivors.