Post on 17-Feb-2017
BSc MSc Computer Science Engineering. PhD (in progress) Applied Machine Learning Head of Data Science - Bloom Technologies Self-Experimenter Maker all things HRV (HRV4Training, Camera HRV, HRV Logger)
Marco Altini - @marco_alt
Degree in Ops Research (Military Analytics) before computers Tracked 1700 negotiation discussions in Europe & Middle East Quantified Selfer, blogger, HRV & Blood Glucose enthusiast
Paul LaFontaine - @QuantSelfLaFont
Autonomic Nervous System
• Sympathetic / Parasympathetic branches
• How do we react to stressors? – Social / Environmental – Physical activity – Psychological stress – Health conditions
Types of measurement
Tools & Best Practices
• 60 seconds PPG measurements: day to day variability due to external stressors (training, travel, etc.), long term baseline changes (burnout?)
• Situational readings: acute stressors, timing of fight/flight, planning factors
60 Seconds PPG Measurements
• Quick snapshot of your physiology (HR+HRV) – Parasympathetic activity
• Low barrier (fast, convenient, no sensors)
• Insightful – If done properly!
Situational Readings
• Indicator of when I go into fight/flight in meetings with others – Parasympathetic activity
• More Preparation (needs heart rate belt)
• Insightful – Measurements can show stress moments
Stress / Burnout prevention
More work ours, but in the zone, reflect in higher baseline HRV (good stress)
Low productivity or burnout, shows
lower HRV
Highly Productive
> 4 hours/day
Highly Productive
< 4 hours/day
Base
line
rMSS
D
Baseline HRV and High Productivity
Training load and recovery A year of data, day to day
differences all over the place (many factors influencing them) After average intensity or
intense training, consistently reduced
Jet-lag and physiological adaptations
HRV HR
1-2 days after traveling Week before
traveling
Week after traveling
Sick days and physiological recovery
HRV HR
1-2 days after getting sick Week before
getting sick
Week after onset
Spot checks: responses to acute stressors
- Spot checks: responses to acute stressors
exercise breathing coffee
60 Seconds PPG Measurements
• PPG works, but very few PPG devices can be used for HRV
• Do your homework on the technology you use (validated against ECGs or Polar’s)
• Or use a Polar J
• Can measure discreetly
• Useful in meetings
• Assured accuracy
• Learn to put on quickly!
HR Belt
Situational Readings
Best Practices for 60 seconds PPG Measurements
• When to take the measurement
– Morning, during the day?, etc.
• What type of measurement – Lying down, sitting, orthostatic?
• Paced breathing – Constrained, unconstrained?
• What metric to use?
– Time domain, frequency domain?
• Are 60 seconds really enough?
When to take the measurement
• First thing after waking up – Relaxed physiological state – Limit all external stressors – Closest to what we do in research /
clinical studies – Don’t read your email before the
measurement!
What type of measurement
• Lying down while still in bed – Limits other factors like not waiting
enough after standing up – Performed in clinical studies – Sitting/Standing also valid, however for
simplicity I’d recommend lying down
Paced Breathing (1/3)
• Improves reliability and repeatability of the measurement – Breathing patterns and RSA have an
impact on HRV values – Using paced breathing provides more
consistent settings (same context!) – Use what works for you (8-12 breaths per
minute typically)
Consistency!
• Choose: – A body position – A paced breathing rate – Waking time (more or less) / measurement
routine
Stick to those
What metric to use?
• HRV is not a single number • Use rMSSD or ln rMSSD – Marker of parasympathetic activity (only
thing you can reliably measure). There is no clear sympathetic marker
– HF, LF, HF/LF or other frequency domain features require more time (and are computed differently by everyone, difficult to generalize/compare)
Best Practices for Situational Readings
• When to take the measurement
– Day part makes a difference (morning, afternoon)
• What type of measurement – Posture control (sitting)
• Paced breathing – When you talk vs. when they talk
• What metric to use?
– RR intervals snapshot vs. rMSSD
• Change Readings: Listen vs. Talk