Operator`s manual
[10] 
HEART RATE VARIABILITY (HRV) 
Long, graceful breathing cycles have long been used as part of meditation. 
Scientifically, this technique has been analyzed and shown to settle down a 
stressed autonomic nervous system. Both sympathetic (flight-or-fight) 
activity and parasympathetic (the brain’s efforts to restore) activity settle 
down dramatically using controlled, slowed, deep-breathing. 
The heart speeds up with every breath in and slows down with every breath 
out. The difference in heart rate between its fastest and slowest rates with 
every breath is called Heart Rate Variability (HRV). For example, a relaxed 
person using controlled breathing may have a heartbeat of 80bpm (beats 
per minute) while breathing in and as low as 65bpm while breathing out. 
The difference or “swing” is about 15bpm. When people get stressed, their 
heart typically clamps as low as 3bpm HRV with occasional spikes 
sometimes as high as 30bpm HRV. This is abnormal activity and is straining 
to the heart. 
WHEN USING HRV-PACED BREATHING, LISTEN TO THE HEARTBEAT 
GENERATED  BY  THE  DELIGHT  PRO  THROUGH THE  HEADPHONES. 
INHALE  FOR  TWO  HEARTBEATS  AND  EXHALE  FOR  TWO 
HEARTBEATS (NOT YOUR OWN HEARTBEATS!). 
The HRV technique used in the DAVID Delight Pro is based on a 10-second 
breathing cycle. All Delight Pro sessions begin at seven breaths/minute (28 
heartbeats/min) and slow to six breaths/minute (24 heartbeats/min). This 
allows for faster breathing at the start of a session, progressing to more 
meditative breathing after the user has had time to relax. 










