Abstract
We studied the effects of the controlled abdominal breathing using the diaphragm on the autonomic nervous system and cardiovascular responses in elderly subjects. Study subjects were 14 participants aged 65-75 years. The subjects seated comfortably on a reclining chair and carried out spontaneous breathing or controlled abdominal breathing at 6 bpm for 15 min after 5 min of spontaneous breathing. Cardiovascular responses during the abdominal breathing were similar to those responses during the spontaneous breathing. Heart rate and systolic blood pressure during abdominal breathing decreased significantly than those at the resting state before abdominal breathing. Using the Lorenz plot methods of the heart rate variability, we analysed the autonomic nervous responses during the abdominal breathing. Abdominal breathing increased significantly log(L × T), which indicated augmented cardiac parasympathetic nervous activities compared to those in the resting state. We also demonstrated that abdominal breathing, but not spontaneous breathing, induced statistically significant changes in both urine noradrenalin and in salivary cortisol in accordance with the decline of stress levels. Our results suggest that abdominal breathing of 6 bpm might actually be opposite to a stressor and could even heighten the managing capacity of stress through the augmented parasympathetic activities.
