Greater parasympathetic activation, measured by the high-frequency component of heart rate variability, was significantly correlated with lower perceived fatigue (ρ=0.521; p=0.010).
Observational (n=10)
In women who have completed chemotherapy for breast cancer, greater parasympathetic activation (measured via vagal-related HRV indices) is associated with lower perceived fatigue.
Effect estimate: ρ=0.521
p-value: p=0.010
Abstract Introduction Advances in diagnostic and therapeutic technologies for cancer have increased survival rates among affected patients. However, these individuals may experience cardiovascular alterations during treatment, including changes in autonomic cardiac control, as reflected by reduced heart rate variability (HRV). Autonomic imbalance appears to be involved in enhanced tumour growth, poorer aerobic fitness, and greater perception of fatigue. Objective To determine whether HRV indices are associated with fatigue intensity and symptoms reported during exertion and at rest in women with breast cancer. Methods This case series included women with breast cancer who had completed chemotherapy. Sociodemographic and clinical data were collected via interview. Cardiac autonomic function was assessed using HRV; submaximal exercise tolerance was evaluated using the six-minute walk test; and quality of life and fatigue were measured using the Functional Assessment of Cancer Therapy–Fatigue (FACT-F). Results The sample consisted of 10 participants (mean age 39.7±7.45 years). All had completed oncology treatment; 70% were undergoing immunotherapy or hormone therapy, and 70% had received anthracyclines. Regarding clinical profile, 60% were physically active, 40% had class I obesity, and 30% presented metastatic disease. The mean LF/HF ratio was 0.69±0.24, indicating a predominance of parasympathetic tone, while the low mean SDNN (36.3±18.8 ms) indicated overall reduced HRV. In terms of exercise tolerance, 80% achieved 80% of their predicted distance on the six-minute walk test (511.4±61.9 m), demonstrating good functional capacity. Positive associations were found between parasympathetic activity and fatigue and quality-of-life indicators. The HF component was the most sensitive autonomic marker, showing moderate to strong correlations with fatigue (ρ=0.521; p=0.010), emotional well-being (ρ=0.534; p=0.010), physical well-being (ρ=0.423; p=0.050), and functional well-being (ρ=0.412; p=0.050). RMSSD, SDNN, and pNN50 also correlated positively with fatigue and emotional well-being (p=0.050). No significant associations were observed with the LF/HF ratio (p0.05), suggesting that isolated vagal activity may be more clinically relevant than sympathovagal balance. Conclusions Greater parasympathetic activation was associated with lower perceived fatigue, highlighting the role of autonomic modulation in subjective fatigue in oncology patients. HRV—particularly vagal-related indices—may represent a promising physiological marker for clinical monitoring and for guiding interventions aimed at reducing fatigue.
Amaral et al. (Mon,) conducted a observational in Breast cancer (n=10). Parasympathetic activity (HRV indices) was evaluated on Correlation between HRV indices and fatigue intensity (ρ=0.521, p=0.010). Greater parasympathetic activation, measured by the high-frequency component of heart rate variability, was significantly correlated with lower perceived fatigue (ρ=0.521; p=0.010).