Biostrap: Research-Grade PPG Wearable
Biostrap is a research-grade wearable ecosystem with dual-site PPG (wrist band + toe clip), raw data export, and clinical-quality HRV measurement. Designed explicitly for researchers and clinicians, Biostrap provides raw PPG waveform access at 128 Hz, making it suitable for algorithmic development and validation studies.
Biostrap distinguishes itself from consumer wearables by prioritizing raw data accessibility and measurement accuracy over form factor. The Evo wristband uses a green LED PPG sensor sampling at 128 Hz with open raw data export via API, enabling researchers to access the underlying waveform rather than only derived metrics. The companion wrist clip (formerly shoe clip) provides an optional secondary site for dual-site PTT measurements and SpO2 estimation using red/IR LEDs at 63 Hz.
HRV performance studies place Biostrap among the most accurate wrist wearables for research applications. Compared to simultaneously measured Polar H10 (chest ECG reference) during sleep, Biostrap shows RMSSD ICC = 0.91–0.94 and SDNN ICC = 0.89–0.93 — significantly better than standard consumer wearables (ICC typically 0.75–0.87). This accuracy is achieved through multiple methodological choices: higher sampling rate (128 Hz vs. 25 Hz), dedicated beat-detection algorithms tuned for research accuracy rather than battery efficiency, and conservative data quality flagging that excludes low-quality epochs rather than interpolating.
Biostrap's clinical research ecosystem includes a HIPAA-compliant cloud platform, REDCap integration for clinical trial data management, and IRB-approved data sharing agreements for academic collaborators. The platform has been used in NIH-funded studies on HRV biomarkers in COVID-19 recovery, PTSD monitoring, and cancer patient fatigue assessment. The trade-off vs. consumer devices is price (~$200 vs. $50–400) and form factor — Biostrap lacks the premium design and social features that drive consumer adoption.
Frequently Asked Questions
What makes Biostrap suitable for research vs. consumer wearables?
Biostrap provides raw PPG waveform export at 128 Hz, rigorous clinical validation against ECG reference, HIPAA-compliant data platform, REDCap integration, and conservative quality flagging rather than interpolation. These features enable algorithmic research and regulatory-grade study design.
Can Biostrap measure PTT (pulse transit time)?
Yes. The dual-site configuration (wrist + toe or wrist + ear) provides two PPG signals from different arterial sites. PTT is computed as the inter-site delay corrected for site-specific cable delays. Biostrap validates this feature against invasive blood pressure for cuffless BP research applications.
Is Biostrap data exportable in standard formats?
Yes. Biostrap provides raw PPG data in CSV and JSON via REST API, compatible with MATLAB, Python pandas, and R. The platform also supports WFDB (PhysioNet) format export for interoperability with PhysioNet toolkits.