GUIDELINES FOR RESEARCH WITH FIRSTBEAT LIFESTYLE ASSESSMENT
- Bodyguard 2 HRV recorder
- HRV and physiological data analysis
- Detailed reporting
- Firstbeat analysis server
- Firstbeat Bodyguard 2
- Firstbeat Lifestyle Assessment
- Reports (pdf)
- Automated heart rate variability (HRV) analysis
- Communication tools and diaries
- Data export for researches
- System requirements and compatible hardware
- Administrative tools and security
- The method is based on physiological modelling of the body based on heart rate variability (HRV) and 3D acceleration data. HRV is a non-invasive tool for exploring autonomic modulation of the heart, including parasympathetic (vagal) and sympathetic effects.
- The software requires some background information about the users [gender, date of birth (age), height, weight, physical activity class]. Based on the background variables, the software seeks from the data and/ or estimates a physiological range for each user (e.g. VO2max, HRmax, HRmin). If this information has been measured in a laboratory, it can be added to the system and it improves the accuracy of the measured parameters.
- It is recommended to have a long enough measurement period, including daytime and sleep time data, to allow full calibration of the system for the individual. Typically, it is better to have data from more than one day for each person. The current service model by Firstbeat is based on 3-day measurements. Note! If only standard HR and HRV parameters are used in research, the individual calibration period is not necessary.
- It is extremely important that there is data only from one person at a time in the device. Therefore, the same device should not be worn consecutively by different people without uploading the data and emptying the device between the measurements as this mixes up the physiological range evaluation for a particular person. The data should always be uploaded, and the device emptied, and the battery charged before attaching the device on the next person.
- If comparable results between different time periods (e.g. pre, post) are to be acquired, it is important to use the same background parameter values in each measurement.
- Research use of the Lifestyle Assessment allows the data to be exported into three separate information sheets, including raw data, HRV data (RMSSD 1 min and 5 min), and overall results as scalars (averages of the whole measurement) and vectors (second-by-second data).
- It is important to have technical skills for analyzing large data sets. For example, Matlab software can be used to extract the desired information from the data sheets to be input for example into the SPSS statistical tool.
- Fever is the most common example of an acute illness that affects strongly on physiology and HRV metrics, seen as reduced recovery. Thus, if comparable results are desired between measurements it is not recommended to conduct a measurement during fever. Strong infections can also significantly weaken recovery.
- The measurement is not recommended for people who have a cardiac pacemaker, have had a heart transplant or suffer from a serious heart condition, chronic atrial fibrillation or flutter or uncontrolled thyroid dysfunction. In these cases, the results can be misleading, or their reliability can be weak.
- If the client has a lot of different illnesses and medications, it can be difficult to draw appropriate conclusions from the result. Thus, the researcher should consider, case-by-case, whether it is sensible to conduct the measurement.
Medications that increase or decrease the heart rate can weaken the reliability of the analysis result by changing the way the nervous system reacts and giving a somewhat misleading view of the body’s stress level, recovery or energy expenditure.
Particularly the following medications can cause challenges in interpreting the result accurately:
- Beta blockers
- Tricyclic or other activating antidepressants
- Long-acting sleep medications
- Pain medications that affect the central nervous system
- Strong medications for psychosis, arrhythmia and neurologic disorders
Beta blockers decrease the heart rate level at rest and during exertion. If the client has listed a beta blocker under Medications, in most cases, it is recommended to reduce the maximum heart rate by 15-20 beats (under personal information), to make the analysis more reflective of the person’s situation.
ALCOHOL AND STIMULANTS
- Alcohol has a big effect on the autonomic nervous system and HRV. There is a dose-response relationship between dosage of alcohol and reduced recovery. As little as two units of alcohol in the evening can elevate the heart rate level for several hours. In order to measure the resting heart rate reliably, it is recommended to have at least one night in the assessment period without any alcohol. In a study where reliable and comparable results between days are desired, it is better to instruct the research subjects to avoid drinking any alcohol during the measurement.
- Other drugs and stimulants, such as cigarettes, chewing tobacco and energy drinks can also increase the heart rate level and cause challenges in determining an accurate resting heart rate. This can weaken reliability, especially when it comes to recovery.
MISSING HEART RATE DATA
- Missing heart rate (%) consists, for example, of measurement breaks (e.g. shower), weak electrode contact with the skin (e.g. very damp skin, poor attachment, or old / dried up electrodes) or some kind of irregular heart rhythm
- A high amount of missing heart rate does not allow the system to get reliable R-R data, which weakens the accuracy of physiological analytics.
- If there is more than 15% / day of missing heart rate data and it occurs systematically throughout the day (instead of 1 long measurement break), the reliability of the result is weakened for that day. If the share of missing data is over 15% on two out of three days, a new measurement is recommended. It’s best to make the new measurement with a different device to rule out possible device failure.
- Very strenuous exercise will have a significant impact on the body’s stress level (physiological activation) for some time after exercise. The harder the exercise session is for the individual, the bigger the impact. Especially late-evening exercise can cause a significant delay before recovery starts during sleep. For the best possible comparison between different days in a research project, or to show the effects of a specific intervention, it is better to avoid very strenuous exercise.
Firstbeat research tool for 24h HRV measurements
Firstbeat provides complete tools for 24h monitoring and analysis of heart rate variability (HRV) and acceleration in real-life measurements. Our methods are used in exercise and training research, behavioral sciences, wellness coaching and health promotion, ergonomics and work studies.
- HRV and autonomic nervous system balance
- Within-day stress and recovery profiles
- Recovery analysis during sleep
- Exercise intensity and physical activity
- Fitness level (VO2max) evaluation
- Energy expenditure
- Workload assessments
BODYGUARD 2 HRV RECORDER
Bodyguard 2 is a lightweight device for measuring 24h HRV (RR-intervals) and 3-axis acceleration. The device is designed for robust and reliable real-life (ambulatory) measurements. The device is attached to a person using two standard electrodes and data is loaded to a PC through USB.
HRV AND PHYSIOLOGICAL DATA ANALYSIS
Firstbeat analysis includes traditional HRV indices and novel measures developed for reflecting sympathetic / parasympathetic balance in 24h assessments. Physiological modelling produces indirect data on exercise intensity (oxygen consumption, VO2), energy expenditure, EPOC, respiration and other physiological parameters.
Detailed reports on HRV, stress and recovery, physical activity, physical workload and energy expenditure. The reports are in pdf-format and can be used to provide lifestyle related feedback. Group reporting and possibility to customize your reports is also available.
FIRSTBEAT ANALYSIS SERVER
Firstbeat has developed a web-based solution for efficient HRV analysis and reporting. The solution is a multi-user environment that includes web-based measurement diaries, automated analysis and error correction and extensive data export. You can find the User Manual here.
FIRSTBEAT BODYGUARD 2
- Weight: 24g
- Size: 47mm x 63mm x 11mm
- Battery: rechargeable Li-Poly battery (recharges through inbuilt USB), charging instructions here
- Battery life: 144 hours
- IP class: IP52 (in recording mode), PI22 (when cable unattached)
- Measurement accuracy: 1 ms (sampling rate 1000 Hz)
- Recording capacity: over 20 days
- 3d accelerometer: Sampling frequency 12.5Hz (max 200 Hz), resolution 8bit (max 16bit), G-scale 4G (configurable to 2G/8G)
- More technical details here
FIRSTBEAT LIFESTYLE ASSESSMENT
Cloud service is available in English, Finnish, Swedish and German
- Individual Reports: Lifestyle assessment, Lifestyle assessment summary, Training effect, Physical workload, Lifestyle assessment follow-up.
- Anonymous group reporting tools: Summary of the Firstbeat Assessment, Physical Workload Group Report, Pre-Questionnaire Group Summary.
- Specialist reports on HRV based stress classification
- Graphs include for example heart rate, stress, recovery and physical activity periods and intensity, HRV, energy expenditure and EPOC.
- Possibility to customize the reports’ visual image.
- Reports are available in English, German, French, Swedish, Hungarian, Norwegian, Portuguese and Finnish.
- Example reports can be found from here.
Automated heart rate variability (HRV) analysis
- Automated correction of measurement errors in beat-by-beat heart rate (required for HRV analysis)
- HRV-based stress and recovery state classification for 24h data, stress and recovery summary indexes (autonomic balance)
- Physical activity measures (indirect): VO2, %VO2max, EPOC, training effect, energy expenditure
- Detection of HRV irregularities
- HRV measures: VLF, LF, HF, LF/HF, RMSSD.
- Analysis has been developed based on physiological autonomic nervous system (ANS) research.
Communication tools and diaries
- Tools supporting personal lifestyle goal setting
- Web-based electronic diary and personal information request tools. Support for email communications.
- Customizable email forms for automated messaging with the customers
Data export for researches
- Option to export second-by-second data or summary data for all HR, HRV and physical activity measures
- Data export in .csv files for single measurements and for multimeasurements
- Profile and data exports/imports in FBE-file format
System requirements and compatible hardware
- Windows or Mac operating system. Screen resolution 1024X768, 16-bit colour package
- Direct upload from Firstbeat Bodyguard 2; Firstbeat Bodyguard via Firstbeat Plugin
Administrative tools and security
- Professional users’ account management
- System statistics and access logs
- Customization tools and system options
- SSL secured communications and password access security
- Built-in user instructions and guidance (Learning Center)
For more information and local distributors, please visit firstbeat.com.
Data files available from Firstbeat analysis server for research use
1) RR-interval Data Export
Firstbeat analysis server contains a data export feature that allows the essential information calculated from heartbeat data to be stored into a .csv file. This file format is compatible with common data analysis programs, e.g. MS Excel and SPSS. Once enabled for the account, the data export feature is available in the main view of the analysis server. To upload the raw data in offline mode, please see the instructions here.
Data export provides three separate files. The first one (_IBI suffix in the file name) contains the analysis version, measurement start time, original and corrected RR data and artifact data that counterparts with corrected RR data and tells if the RR-interval is modified with artifact correction. The second file (_MiscVectors suffix in the file name) contains the analysis version and an RMSSD vector in 5- and 1-minute sampling frequency. The third file is the main export file containing the most essential analysis results.
The table describes the main export file (.csv format) produced by the Data export. One file includes data from a single analyzed session. The file consists of PERSON PROFILE info, SCALAR VARIABLES and VECTORS. PERSON PROFILE includes the personal background values used in the analysis. SCALAR VARIABLES are average values calculated for the session and VECTORS show the values from each respective moment of the session. The sampling frequency of the vectors is one second, meaning that each data point corresponds to one second in time, i.e. a vector that is 120 points long corresponds to two minutes in time.
Please find the table on PDF file attached.
2) Acceleration data export
Firstbeat Bodyguard measures 3D acceleration. You can find the acceleration data (.csv) on your computer. The path is (for example) C:\Firstbeat Files\Uploader Plugin\Eddie Example\Loaded RR files.
Figure 1. An example acceleration data file in Excel
The accelerometer measures acceleration in these directions:
- X: up – down
- Y: right – left
- Z: forward - backward
The default setting means, in short, that each direction can get a value between -127 - +127, where the highest / lowest value is reached when the force of gravity in that direction is 4G or more.
For example, if you stand / sit still:
- X ~= -32 (force of gravity)
- Y ~= 0
- Z ~= 0
If you are absolutely sure that you want to use some other accelerometer settings than the recommended default settings in your research, you can change the settings in Firstbeat Uploader (Configure device-> Advanced settings-> Accelerometer settings). Remember that the higher resolution sampling mode use more memory and battery.