Visual impairment can significantly affect psychological and physiological well-being, potentially due to autonomic imbalance, and while deep breathing has been shown to improve autonomic modulation as measured by heart rate variability (HRV), its impact on individuals with visual impairment remains underexplored, prompting this study to investigate its immediate and long-term effects on HRV in this population compared to normally sighted individuals.

A total of 98 participants with visually impaired (VI) individuals (n = 49) and normally sighted (NS) individuals (n = 49) were recruited. The HRV, including standard deviation of the normal-to-normal intervals (SDNN), root mean square of successive differences, normalized low frequency (nLF), normalized high frequency (nHF), and low frequency to high-frequency ratio (LF/HF), was measured at baseline (BL), immediate post intervention (IPI) and post-intervention (POST) after 2 weeks daily audio-guided deep breathing.

Kruskal-Wallis tests revealed significant phase effects for nLF (p = 0.002), nHF (p = 0.002), and LF/HF (p = 0.024) in the VI group, with post hoc analyses indicating significantly higher nLF (p = 0.004), LF/HF (p = 0.007), and lower nHF (p = 0.004) at IPI compared to BL. While the NS group showed no significant changes across phases. Between-group comparisons revealed significantly higher nLF (p = 0.034), LF/HF (p = 0.007), and lower nHF (p = 0.034) at IPI in the VI group compared to the NS group.

Deep breathing led to immediate increases in nLF and LF/HF, and a decrease in nHF, in individuals with visual impairment compared to sighted individuals, suggesting baroreflex resonance at 0.1 Hz. However, the absence of significant SDNN changes limits conclusions about parasympathetic modulation. Further research is needed to assess the potential long-term benefits.