Highlights
- Regional brain oxygenation increased by 22%.
- Mean heart rate decreased by 8%.
- SDNN increased from 12 to 51 ms, and RMSSD from 10 to 67 ms.
- Peripheral pulse transit time increased by 46%, alongside other circulation-related changes.
An 81-year-old participant completed a single 20-minute AVACEN session during an exploratory assisted living facility study. Researchers assessed brain oxygenation-related measurements, heart rate, heart rate variability, autonomic balance, and peripheral circulation immediately before and after the session.
A change in brain oxygenation
The brain relies on a continuous blood supply to deliver oxygen and nutrients. Regional cerebral blood oxygenation provides information related to the amount of oxygenated blood present in the brain region being assessed.
For this participant, regional cerebral blood oxygenation increased by 22%, from 28 to 34.2, following the session.
An increase in an oxygenation-related measure can be interesting because oxygen delivery is essential for normal brain activity. However, this measurement alone cannot show whether brain function or cognition improved.
A notable heart rate variability response
Mean heart rate decreased by 8%, from 73.9 to 68.1 beats per minute.
At the same time, substantial changes occurred in heart rate variability (HRV)—the natural variation in timing between heartbeats that gives researchers information about autonomic regulation of the heart.
SDNN increased from 12 to 51 ms and RMSSD increased from 10 to 67 ms. Expressed as percentages, these represent increases of 325% and 570%, respectively. Total Power increased by 55%.
The large percentages partly reflect the participant’s low starting values, which is why the actual before-and-after numbers are important when interpreting the change.
A shift toward “rest-and-recover”
The autonomic nervous system has two major branches. The sympathetic branch is associated with greater alertness and the “fight-or-flight” response, while the parasympathetic branch supports the body’s “rest-and-recover” functions.
After the session, the sympathetic-related measure decreased by 38%, while the parasympathetic-related measure increased by 44%.
Together with the lower heart rate and changes in HRV, this pattern suggests an acute shift in autonomic regulation toward greater parasympathetic influence.
Changes in peripheral circulation and vascular response
Several circulation-related measures also increased after the session.
Bilateral Flow Gain, which provides information about peripheral blood flow-related changes on both sides of the body, increased by 11% on the left and 26% on the right. The Perfusion Index, a measure related to blood flow reaching peripheral tissues, increased by 30%.
Another measure, peripheral pulse transit time (PPT), increased from 92.3 to 134.9 ms—a 46% increase. PPT reflects the time it takes for the pulse wave created by each heartbeat to travel through the peripheral circulation. Changes in this measure provide additional information about vascular and circulatory behavior following the session.
Taken together, the increases in Flow Gain, Perfusion Index, and PPT indicate a measurable short-term peripheral circulation and vascular response following the session.
This case describes one participant’s acute response and should not be interpreted as an expected outcome for every AVACEN user. It does, however, provide an interesting example of simultaneous changes across brain oxygenation, heart rate variability, autonomic activity, and peripheral circulation.
