Overview
This lecture explains heart rate variability (HRV), its health benefits, and how breathing techniques can be used to improve HRV and induce calm.
Heart Rate Variability (HRV) Basics
- HRV is the variation in time intervals between consecutive heartbeats.
- High HRV is associated with positive health outcomes, longevity, and better performance.
- HRV reflects a healthy balance in the autonomic nervous system.
Biological Mechanisms of HRV
- The vagus nerve regulates heart rate through its influence on the sinoatrial (SA) node.
- Inhalation increases heart rate by expanding the thoracic cavity and sending sympathetic signals.
- Exhalation slows heart rate by compressing the heart and triggering parasympathetic activity.
- These processes occur unconsciously during sleep and wakefulness.
Neurological Control and Conscious Regulation
- The left dorsolateral prefrontal cortex can voluntarily influence heart rate via breathing.
- Deliberately extending your exhale activates the parasympathetic nervous system, promoting calm.
Breathing Techniques for HRV and Calm
- The "physiological sigh" involves two nasal inhales followed by a long, slow exhale through the mouth.
- The physiological sigh quickly increases parasympathetic activity and calms the body.
- Emphasizing longer exhales, even without the full sigh pattern, also slows heart rate and increases HRV.
Practical Application and Benefits
- Practicing extended exhales throughout the day strengthens neural pathways involved in HRV regulation.
- Strengthened pathways help maintain higher HRV during sleep and wakefulness, even unconsciously.
- Regular practice of slow exhales confers both immediate and long-term health benefits.
Key Terms & Definitions
- Heart Rate Variability (HRV) — the variation in time between each heartbeat.
- Vagus Nerve — a cranial nerve that regulates heart rate via the parasympathetic nervous system.
- Sinoatrial (SA) Node — the heart's natural pacemaker.
- Parasympathetic Nervous System — part of the autonomic nervous system that promotes relaxation.
- Sympathetic Nervous System — part of the autonomic nervous system that prepares the body for stress.
Action Items / Next Steps
- Practice the physiological sigh (two nasal inhales, one slow mouth exhale) to quickly induce calm.
- Frequently incorporate extended, slow exhales during your day to improve HRV.
- Aim to do slow exhales 10–20 times per day as a regular habit.