Average of valid rr interval: Average of (NN_interval) calculated over the last 5 minutes.

• Source data: NN_interval, RR_interval_quality and RR_interval which are based on ecg
• method of calculation
  • calculated on server
  • Average calculated on the valid RR interval (NN interval) during the last 5 minutes
• Frequency 1/300Hz = 1/5min
• Unit: second
• Unit (binary download): second/4096

Acceleration: 3-axis sensors with a 13 bits resolution.

• Frequency: 64 Hz
• Resolution 3.90625 mG
• Dynamic range +- 16G
• Unit: G
• Unit (binary download): G/256

Activity: Signal based on the accelerometer intensity vector.

• Source data: acceleration
• Method of calculation:
  • Highpass at 2.65 Hz on the 3 axis independently
  • Vector of acceleration. (accX^2 + accY^2+accZ^2)^.5
  • Averaged over the last second
• Frequency: 1 Hz
• Resolution 3.9 mG.
• Dynamic range +- 16G
• unit G
• Unit (binary download): G/256

Breathing rate: Calculated over the last 7 respiration cycles.

• Frequency: 1 Hz
• Source data: inspiration expiration which are based on respiration
• Quality score: breathing_rate_quality
• Average: last 7 respiration cycles
• Valid range: (2 to 60 RPM)
  • If BR > 60: Clip to 60
  • If BR < 2: set to 2
• Value on initialisation: 10 RPM, then average of last 2,3,4,5,6 respirations, then average of last 7 respirations
• Behavior on invalid detection: keep value of last valid BR
• Unit: respiration per minute

Breathing rate status: Quality of breathing rate signal.

• Source data: respiration
• Frequency: 1Hz
• Bits description:
  • NoBit, RESP_STATUS_OK (0x00), Resp good quality.
  • BIT0, RESP_STATUS_NO_A (0x01, 1), Resp channel A (thoracic) is disconnected.
  • BIT1, RESP_STATUS_NO_B (0x02, 2), Resp channel B (abdominal) is disconnected.
    • Flag is raised if signal is always zero for the last 2 seconds
  • BIT2, RESP_STATUS_BASELINE_A (0x04, 4), Resp A (thoracic) baseline has changed.
  • BIT3,RESP_STATUS_BASELINE_B (0x08, 8), Resp B (abdominal) baseline has changed.
    • Flag is raised if a sample of the signal is further away than 500 units from the baseline in the last 2 seconds.
  • BIT4, RESP_STATUS_NOISY_A (0x10, 16), Resp A (thoracic) has high frequency content.
  • BIT5, RESP_STATUS_NOISY_B (0x20, 32), Resp B (abdominal) has high frequency content.
    • Flag is raises if we detect more than 20 zero crossing in the last second

Cadence: Averaged over the last 7 strides based on the accelerometer.

• Frequency: 1 Hz
• Source data: acceleration
• Method of calculation:
  • Average: last 8 steps detected (7 strides) sampled each second
  • Lowpass @ 0.17Hz
• Valid range: (30 to 240 Steps per minute or SPM)
  • If cadence > 240: Clip to 240
  • If cadence < 30: set to 0
• Unit: Steps per minute

Device position: Give the onset of a position changes.

|Position    |Axis pointing upward  |Device position    |
|:-----------|:--------------------:|:-----------------:|
|Position 1  | y                    |Blue LED upward    |
|Position 2  |-y                    |Blue LED downward  |
|Position 3  | z                    |Face downward      |
|Position 4  |-z                    |Face upward        |
|Position 5  | x                    |Wire downward      |
|Position 6  |-x                    |Wire upward        |
|Position 0  |                      |Undefined          |

Note: For sleep position, see sleep_position

• Source data: acceleration
• Frequency: Async

Electrocardiogram: 1 to 3 lead ECG channel with a 12 bits resolution. ECG_II and ECG_III are available only on the Hexoskin-X and Astroskin models.

• Frequency: 256 Hz
• Filter: Bandpass filter @ 1.6–33.9 Hz
• Resolution LSB: 6.4 μV
• Dynamic range: 26 mV
• unit: μV * 6.4
• Unit (binary download): μV * 6.4

Total energy based on ECG. We used Mifflin and Keytel equation. The value are adjusted for the weight, height,sex, HRMax, HRMin of the user.

• Frequency: 1 Hz
• Unit: Watt
• Unit (binary download): Watt

Expiration: Detection of an expiration onset event.

• Method of calculation:
  • The inspiration and expiration are detected on the ponderate sum of the thoracic and abdominal sensor.
  • A history buffer is created which correspond to a memory of =.75 s.
  • At each sample, check if the oldest point is a maximum. If it's the case and if the signal decrease of more than 10 units since the last inspiration, the expiration is saved.
• Frequency: Async
• Source data: respiration
• Quality score: breathing_rate_quality

HRV HF power: (Where: LF=0.04-0.15 Hz and HF= 0.15-0.4 Hz). HF is calculated using the lomb periodogram.

• Method of calculation:
  • Lomb periodogram is calculated on the last valid nn_interval during the last 300 s If there is not enough e_rr valid, return 0
• Frequency: 1/300 Hz
• Source data: NN_interval, RR_interval_quality, heart_rate_quality
• Unit: ms^2
• Unit (binary download): ms^2 /10
• Resolution: ms^2 /10

HRV power LF normalized: LF/(LF +HF) (Where: LF=0.04-0.15 Hz and HF= 0.15-0.4 Hz) LF and HF are calculated using the Lomb Periodogram.

• Method of calculation:
  • Lomb periodogram is calculated on the last valid nn_interval over the last 300s. If there is not enough valid e_rr, it returns 0.
• Frequency: 1/300 Hz
• Source data: NN_interval, RR_interval_quality, heart_rate_quality
• Unit: None
• Unit (binary download): 1/10000

HRV LF power: (Where: LF=0.04-0.15 Hz and HF= 0.15-0.4 Hz). LF is calculated using the lomb periodogram.

• Method of calculation:
  • Lomb periodogram is calculated on the last valid nn_interval during the last 300 s If there is not enough e_rr valid, return 0
• Frequency: 1/300 Hz
• Source data: NN_interval, RR_interval_quality, heart_rate_quality
• Unit: ms^2
• Unit (binary download): ms^2 /10
• Resolution: 1 ms^2 /10

HRV triangular index: HRV triangular index(NN_interval) calculated over the last 5 minutes.

• Source data: NN_interval, RR_interval_quality and RR_interval which are based on ecg
• method of calculation
  • calculated on server
  • Standard deviation calculated on the valid RR interval (NN interval) during the last 5 minutes
• Frequency 1/300Hz = 1/5 min
• Resolution: 0.01
• Unit: None
• Unit (binary download): percent

Heart rate: Average over the last 16 heart beats.

• Frequency: 1 Hz
• Source data: RR_interval_quality and RR_interval which are based on ecg
• Method of calculation:
  • On a QRS detection, if the ECG_STATUS_UNRELIABLE_RR is set to off, the HR is put in the 32 HR buffer. Then the HR is calculated as the average on the last 16 HR.
  • On initialisation HR is set to 70 BPM.
• Quality score: heart_rate_quality
• Average: last 16 beats
• Valid range: 30 to 220 BPM.
  • Range is defined by the limits fixed on RR_interval_quality
• Value on initialisation: 70 BPM
• Behavior on invalid detection: keep value of last valid HR
• Unit: BPM

Heart rate status: Quality of heart rate signal.

• Source data: ecg
• Frequency: 1Hz
• Bits description:
  • NoBit, ECG_STATUS_OK (0x00) ECG good quality
  • BIT0, ECG_FOR_FUTURE_USE (0x01, 1) reserved to reach heart ECG
  • BIT1, ECG_STATUS_DISCONNECTED (0x02, 2) Shirt is disconnected
  • BIT2, ECG_STATUS_50_60HZ (0x04, 4) 50-60 Hz dominant in ECG.
    • Flag is raises if we detect more than 80 zero crossing in the last second
  • BIT3, ECG_STATUS_SATURATED (0x08, 8) ECG signal saturated
    • Flag is raised if amplitude is <=0 or amplitude is >=4096 during the last second
  • BIT4, ECG_STATUS_ARTIFACTS (0x10, 16) Movement artifacts makes RR intervals less precise
  • BIT5, ECG_STATUS_UNRELIABLE_RR (0x20, 32) ECG ok, but some RR are unreliable
    • Build an histogram with the last 32 rr interval. The bins of the histogram are fixed in __rr_histogram= [0, 273, 301, 324, 363, 414, 473, 539, 613, 719, 855, 1023, 1230, 1477, 1770, 2125, 2551, 3000] ms.
    • The flag is raised one rr is outside the 5 centered bins of the histogram in the last second
    • The flag is raised if outside the outer limits (220 bpm to 30 bpm)

Inspiration: Detection of an inspiration onset event.

• Method of calculation:
  • The inspiration is detected on the ponderate sum of the thoracic and abdominal sensor.
  • A history buffer is created which correspond to a memory of =.75 s.
  • At each sample, check if the oldest point is a minimum. If it's the case and if the signal decrease of more than 10 units since the last expiration, the inspiration is saved.
• Frequency: Async
• Source data: respiration
• Quality score: breathing_rate_quality

Minute ventilation: volume of air/minute inspired in the last 7 complete respiration cycles. The value is ajdusted to take into account the user profile, for raw data see minute_ventilation.

• Frequency: 1 Hz
• Average: last 7 complete respiration cycles
• Unit: mL/min
• Unit (binary download): cL/min

Minute ventilation: volume of air/minute inspired in the last 7 complete respiration cycles. This value is based on the raw signal, you are probably looking for minute_ventilation_adjusted.

• Frequency: 1 Hz
• Average: last 7 complete respiration cycles
• Unit: mL/min
• Unit (binary download): mL/min * 13.28

NN interval: Time between to heart beat detections, calculated for every QRS event.

• Method of calculation:
  • The time difference between the QRS and the previous QRS.
  • Range of validity: from eye-closing period 0.265s to 4s
  • The nn interval are based on the RR_interval where unreliable RR_intervals are excluded. Moreover a RR_interval differing by more that 150 ms from the 5 adjacent RR_intervals is also excluded.
• Frequency: Async
• Source data: QRS, RR_interval_quality ecg
• Unit: second
• Unit (binary download): second/256

NN/RR: Ratio len(NN_interval) / len(RR_interval): over the last 5 minutes. This can give a quality score for the HRV results.

• Source data: RR_interval,NN_interval RR_interval_quality, heart_rate_quality
• Frequency: 1/300 Hz
• Unit: percent
• Unit (binary download): 1/10000

Pulse oximetry derivated HR channel. Available only on the Hexoskin-X and Astroskin models.

• Frequency: 1 Hz
• Resolution: 1 BPM
• Unit: BPM

Photoplethysmography: Signal as returned by A Nonin optic sensor. Available only on the Hexoskin-X and Astroskin models.

Note: This signal is not exactly aligned with the other channels (~0.05 s delay).

• Frequency: 64 Hz

Pulse transit time: Time difference between the Nonin PPG digital output http://www.nonin.com/wp-content/uploads/2018/09/OEM-III-PPG-Digital-Output-Feature.pdf and the QRS.

Note: The Nonin PPG digital output is delayed by 172 ms. The time and value of the PTT should be reduce by 172 ms to obtain the value at 50% of the PPG signal. Available only on the Hexoskin-X and Astroskin models.

• Source data: QRS, SPO2
• Method of calculation:
  • Time difference between the peak in PPG and the QRS
• Frequency: Async
• Unit: second
• Resolution: 1/256s
• Unit (binary download): second/256

QRS: ECG ventricular contraction (heart beat) event detection centered on the QRS complex. DEPRECATED QRS location should be accessed through RR_interval

• Method of calculation:

• Frequency: Async

• Source data: ecg
• Range: N-A.
• Quality: RR_interval_quality Note: the QRS position can have a temporal error bigger than 10 ms. To have QRS more precise, use nninterval channel(datatype 318).

RR interval: Time between two heart beat detections, calculated for every QRS event. Saved at the center of the QRS complex

• Method of calculation:
  • The time difference between the QRS and the previous QRS.
  • Range of validity: from eye-closing period 0.265s to 4 s
• Frequency: Async
• Source data: QRS which is based on ecg
• Quality: RR_interval_quality
• Unit: second
• Unit (binary download): second/256

QRS status: Status of the last QRS.

• Frequency: Async
• Method of calculation:
  • Build an histogram with the last 32 rr interval. The bins of the histogram are fixed in __rr_histogram= [0, 70, 77, 83, 93, 106, 121, 138, 157, 184, 219, 262, 315, 378, 453, 544, 653, 768}].
  • The flag is raised if the last rr is outside the 5 centered bins of the histogram
  • The flag is raised if outside the outer limits ( 220 BPM - 30 BPM)
• Bits description:
  • NoBit, RELIABLE_RR (0x00) QRS good quality
  • BIT0, NOISY_RR (0x01, 1) QRS detected in signal with noise
  • BIT7, UNRELIABLE_RR (0x80, 128)

Respiration: 1 to 2 RIP (Respiratory inductance plethysmography) sampled at 128 Hz with a 16 bits resolution.

Note: This is the raw oscillation count and not the volume. A decrease in raw value corresponds to an increase in volume.

• Frequency: 128 Hz
• Raw data (oscillation count in 1/128s)
• Resolution LSB = 128 Hz. i.e. 1 count in 1/128s
• Estimated resolution 8 mL
• Unit: mL
• Unit (binary download): NA

Standard deviation of valid rr interval (NN_interval) calculated over the last 5 minutes.

• Source data: NN_interval, RR_interval_quality and RR_interval which are based on ecg
• method of calculation
  • calculated on server
  • Standard deviation calculated on the valid rr interval (nn interval) during the last 5 minutes
• Frequency 1/300Hz = 1/5 min
• Unit: second
• Unit (binary download): second/4096

SPO2 status: Quality of the SPO2 signal. Available only on the Hexoskin-X and Astroskin models.

• Frequency: 1 Hz

Bit positions:

• BIT0-1: Perfusion Code
• 0: None
• 1: Red
• 2: Green
• 3: Yellow
• BIT2: Sensor alarm (0x04, 4)
• BIT3: Out of track (0x08, 8)
• BIT4: Artifact detected (0x10, 16)
• BIT5: Sensor disconnected (0x20, 32)
• BIT6: HR from SPO2 Unreliable (0x40, 64)
• BIT7: SPO2 unreliable (0x80, 128)

Sleep phase: Give the onset of a sleep phase changes - The phases are:

• 6: Wake
• 5: REM (rapid eye movement)
• 2: NREM (Non REM)
• 0: Non Data
• 1,3,4: Non REM, stage 1,3,4. Theses stages are not used and are regrouped with #2
• Frequency: Async
• Source data: activity, heart_rate, breathing_rate

Sleeper position: Give the onset of a position changes.

|Position    |Axis pointing upward  |Device position       |Sleep position (returned on dashboard)
|:-----------|:--------------------:|:--------------------:|:------------------------------------:
|Position 1  | y                    |Blue LED upward       |Belly (1)
|Position 2  |-y                    |Blue LED downward     |Back (2)
|Position 3  | z                    |Face downward         |Right (3)
|Position 4  |-z                    |Face upward           |Left (4)
|Position 5  | x, -x                |Wire downward/upward  |Standing (5)
|Position 0  |                      |Undefined             |

Notes:

• The sleep positions are defined when the device is placed in the pocket with the wire pointing upward, the light pointing outside and the device on the side of the body
• For device position see device_position Source data: acceleration
• Frequency: Async

SPO2: Oxygen saturation level as returned by A Nonin optic sensor. Available only on the Hexoskin-X and Astroskin models.

• Frequency: 1 Hz
• Resolution 1%
• Unit: percent

Step: The number of steps since the beginning of a recording.

• Method of calculation:
  • Lowpass at 17 Hz
  • Find gravity aligned channel
  • Bandpass 0.466 - 3.782 Hz
  • Step detected if filtered channel goes over 35 units
• Frequency: Async
• Source data: acceleration
• Unit: step

Systolic blood pressure: Blood pressure derived from the PTT value Adjusted for user specs. Available only on the Hexoskin-X and Astroskin models.

• Source data: PTT and QRS
• Frequency: 1 Hz
• Resolution: 1 mmHg
• Dynamic range: 60-260 mmHg
• Unit: mmHg

Systolic blood pressure: Blood pressure derived from the PTT value. Available only on the Hexoskin-X and Astroskin models.

• Source data: PTT and QRS
• Frequency: 1 Hz
• Resolution: 1 mmHg
• Dynamic range: 60-260 mmHg
• Unit: mmHg

Systolic blood pressure status: Blood pressure status derived from the PTT value. Available only on the Hexoskin-X and Astroskin models.

• Source data: PTT and QRS
• Frequency: 1 Hz
• Unit: NA
• Bits description:
  • BP_STATUS_OK (0x00)
  • ECG_OFF_NOMINAL (0x01)
  • PPG_OFF_NOMINAL (0x02)
  • DELAY_OFF_NOMINAL (0x04)

Temperature. Available only on the Hexoskin-X model.

• Frequency: 1 Hz
• Unit: Celcius

Temperature of the respiration sensor. Available only on the Hexoskin-X and Astroskin models.

• Frequency: 1 Hz
• Resolution: 0.01 Celcius
• Unit (binary download): 0.01 Celcius
• Unit: Celcius

Temperature status: Quality of the temperature signal. Available only on the Hexoskin-X and Astroskin models.

• Frequency: 1 Hz

Tidal volume: Volume of air inspired in the last inspiration. The value is ajdusted to take into account the user profile, for raw data see tidal_volume.

• Unit: mL (mL / inspiration)
• Unit (binary download): mL
• Frequency: 1 Hz

Tidal volume: Volume of air inspired in the last inspiration. This value is based on the raw signal, you are probably looking for tidal_volume_adjusted.

• Frequency: 1 Hz
• Unit: mL (mL / inspiration)
• Unit (binary download): mL/min * 13.28