Research & Publications

Research interests

My research interest is mainly in the application of machine learning methods to healthcare and sports applications. Particularly, in using technology and data science to advance our knowledge on the relation between physiological, behavioral, lifestyle parameters and health & performance. There are two aspects driving my work:

Empowering the individual decision-making process with accurate, transparent, and effective tools such as HRV4Training and HRV4Biofeedback — this step typically requires validating the accuracy of measurements with respect to a reference system. For example, our camera-based technology which I have developed 7+ years ago has been validated (see our paper here), and independently validated (see here). You can learn more about the tools I have built, here.
Generating insights arising from crowdsourcing research by providing consumers with accurate grade tools and analyzing user generated data at a scale beyond what was possible in regular clinical studies — this is what I try to teach aspiring data scientists in sports science at VU Amsterdam, and often cover in papers and blogs.

Most of the work listed below focusses on this approach (about 50 publications and a few patents).

topics

This page is organized by topic:

Physiology (HRV, exercise heart rate, etc.) & sports performance (HRV4Training). Currently active.
Prenatal health (Bloomlife). 2014-2019.
Physical activity (PhD Eindhoven University of Technology, imec). 2012-2015.
System integration (imec, University of Bologna). 2009-2011.

PHYSIOLOGY, HEALTH AND PERFORMANCE (Currently active)

You can follow our research on physiology (Heart Rate Variability at rest as well as other metrics collected during exercise) and performance on Research Gate, where we have a project page, here. Similarly, much of my work in this space is covered on the HRV4Training Blog or my Substack.

Publications

2024. R.J. Burden, M. Altini, E. Ferrer, T. Flood, G. Lewin, S. Nimphius, S.M. Phillips, K.J. Elliott-Sale, "Measure don’t guess; a call to end assumed and estimated menstrual cycle phases in research and practice". BMJ.
2024. M. Mirto, L. Filipas, M. Altini, R. Codella, A. Meloni. "Heart Rate Variability in Professional and Semi-Professional Soccer: A Scoping Review". Scandinavian Journal of Medicine and Science in Sports.
2024. M. Altini, "How Data Can Capture Recovery: The Case for Heart Rate Variability". Link here.
2023. de Zambotti, Massimiliano; Goldstein, Cathy ; Cook, Jesse; Menghini, Luca; Altini, Marco; Cheng, Philip; Robillard , Rebecca. Practical Guidelines for Using Wearable Technology in Sleep and Circadian Research: A Position Statement from the Sleep Research Society.
2021. M. Altini, L. Dunne, "What's Next For Wearable Sensing?", IEEE Pervasive Computing, here.
2021. M. Altini, D. Plews, "What Is Behind Changes in Resting Heart Rate and Heart Rate Variability? A Large-Scale Analysis of Longitudinal Measurements Acquired in Free-Living". Sensors. Full text here.
2021. M. Carrasco-Poyatos, A. González-Quílez, M. Altini, A. Granero-Gallegos, "Heart rate variability-guided training in professional runners: effects on performance and vagal modulation". here.
2021. M. Altini, H. Kinnunen, "The Promise of Sleep: A Multi-Sensor Approach for Accurate Sleep Stage Detection Using the Oura Ring". Sensors. Full text here.
2021. T. Gronwald, S. Berk, M. Altini, L. Mourot, O. Hoos, B. Rogers, "Real-time estimation of aerobic threshold and exercise intensity distribution using fractal correlation properties of heart rate variability: A single-case field application in a former Olympic triathlete". Frontiers in Sports and Active Living: Elite Sports and Performance Enhancement. Full text here.

2020. M. Altini, "Heart rate variability is representative of an altitude camp in elite triathletes", Master's thesis, Vrije Universiteit Amsterdam. Presentation slides here.
2020. M. Altini, S. Berk, T.W.J. Janssen, "Heart rate variability during the first week of an altitude training camp is representative of individual training adaptation at the end of the camp in elite triathletes", Sport Performance and Science Reports.
2020. E. Piatrikova, N. Willsmer, M. Altini, M. Jovanovic, L. Mitchell, J. Gonzalez, A. Sousa, S. Williams "Monitoring the heart rate variability responses to training loads in competitive swimmers using a smartphone application and the Banister Impulse-Response model" International Journal of Sports Physiology and Performance.

2018. M. Altini, O. Amft, "Estimating running performance combining non-invasive physiological measurements and training patterns in free-living", accepted for publication at EMBC 2018. Full text here.

2017. M. Altini, O. Amft, "Relation Between Estimated Cardiorespiratory Fitness and Running Performance in Free-Living: an Analysis of HRV4Training Data", accepted for publication at BHI 2017. Full text here.
2017. D.J. Plews, B. Scott, M. Altini, M. Wood, A.E. Kilding and P.B. Laursen, "Comparison of heart rate variability recording with smart phone photoplethysmographic, Polar H7 chest strap and electrocardiogram methods", accepted for publication in the International Journal of Sports Physiology and Performance. Full text here.
2017. S. Williams, T. Booton, M. Watson, D. Rowland, M. Altini, "Heart Rate Variability is a Moderating Factor in the Workload-Injury Relationship of Competitive CrossFit™ Athletes" Journal of Sports Science and Medicine. Full text here.

2016. M. Altini, O. Amft, "HRV4Training: Large-Scale Longitudinal Training Load Analysis in Unconstrained Free-Living Settings Using a Smartphone Application", accepted for publication at EMBC 2016. download pdf.

Prenatal health (2014-2019)

At Bloomlife I worked on combining data collected in clinical settings as well as consumer generated data to help shedding light on many poorly understood links between physiological changes naturally occurring during pregnancy, behavior and pregnancy outcomes. More specifically, my work focussed on contractions detection, fetal movement detection, labour detection, stress estimation, behavior monitoring & context recognition (activity) as well as on building new models to link these parameters to pregnancy outcomes.

You can follow our research on pregnancy on Research Gate, where we have a project page, here.

Publications

2019. M. Altini et al. "Early labour detection in laboratory and free-living conditions using combined electrohysterography and heart rate data" accepted for The Society for Maternal & Fetal Medicine.

2018. M. Altini et al. "Towards non-invasive labor detection: a free-living evaluation" accepted for EMBC 2018. Full text at this link.
2018. M. Altini et al. "Towards personalized and non-invasive labor detection using bloomlife pregnancy tracker" accepted for BHI 2018.

2017. M. Altini et al. "Combining Electrohysterography and Heart Rate Data to Detect Labour" accepted for BHI. Full text at this link.
2017. M. Altini et al. "Variable-Length Accelerometer Features and Electromyography to Improve Accuracy of Fetal Kicks Detection During Pregnancy Using a Single Wearable Device" accepted for BHI. Full text at this link.
2017. M. Altini et al. "Remote labour detection using maternal electrohysterography and heart rate data acquired with a wearable sensor" accepted for The Society for Maternal & Fetal Medicine.
2017. M. Altini et al. "37: a mobile preterm birth calculator" accepted for The Society for Maternal & Fetal Medicine.

2016. M. Altini et al. "Detection of Fetal Kicks Using Body-Worn Accelerometers During Pregnancy: Trade-offs Between Sensors Number and Positioning", accepted for publication at EMBC 2016. download pdf.

2015. J. Penders, M. Altini, C. van Hoof, E. Dy, "Wearable Sensors for Healthier Pregnancies", accepted for publication in the Proceedings of the IEEE.

Patents

2014. Application submitted: "A method and system for biometric and context based messaging"
2014. Application submitted: "System and Method for Detecting and Quantifying Deviations from the Physiological Signals Normality of a Subject"

PhD - physical activity (2012-2015)

In 2015 I obtained my PhD cum laude (top 5%) in applied machine learning at Eindhoven University of Technology. My PhD research at TU/e focused on applying machine learning learning techniques to develop methods and models to derive personalized assessment of physical activity and health markers, using data obtained with wearable sensors. In particular, I've designed context recognition frameworks to contextualize physiological data in free living, and then use contextualized physiological data to better estimate energy expenditure and cardiorespiratory fitness level, without requiring any individual calibration or laboratory tests. My work during this period was featured on IEEE JBHI and licensed to multiple partners in the high-end fitness industry.

Publications

PhD thesis: "Personalization of energy expenditure and cardiorespiratory fitness estimation using wearable sensors in supervised and unsupervised free-living conditions". download pdf.
2016. M. Altini, P. Casale, J. Penders, O. Amft, "Cardiorespiratory fitness estimation in free-living using wearable sensors" accepted for publication in Artificial Intelligence in Medicine. download pdf.
2016. M. Altini, P. Casale, J. Penders, O. Amft, "Cardiorespiratory fitness estimation using wearable sensors: laboratory and free-living analysis of context-specific submaximal heart rates". Accepted for publication in the Journal of Applied Physiology. download pdf.

2015. M. Altini, P. Casale, J. Penders, O. Amft, "Personalization of Energy Expenditure Estimation in Free Living Using Topic Models" accepter for publication in the Journal of Biomedical and Health Informatics, special issue on Sensor Informatics and Quantified Self. download pdf. The article was featured as research highlight on JBHI.
2015. M. Altini, P. Casale, J. Penders, O. Amft, "Personalized Cardiorespiratory Fitness and Energy Expenditure Estimation Using Hierarchical Bayesian models" accepted for publication in the Journal of Biomedical Informatics. download pdf.

2015. M. Altini, J. Penders, O. Amft, "Estimating Oxygen Uptake During non-Steady-State Activities and Transitions Using Wearable Sensors" accepted for publication in IEEE Journal of Biomedical and Health Informatics. download pdf.
2015. P. Casale, M. Altini, O. Amft, "Transfer Learning in Body Sensor Networks using Ensembles of Randomised Trees" accepted for publication in IEEE Internet of Things Journal.

2014. M. Altini, J. Penders, R. Vullers, O. Amft. "Personalizing Energy Expenditure Estimation Using Physiological Signals Normalization During Activities of Daily Living" Physiol. Meas. 35 (2014) 1797-1811. download pdf.
2014. M. Altini, J. Penders, R. Vullers, O. Amft. "Estimating Energy Expenditure using Body-Worn Accelerometers: a Comparison of Methods, Sensors Number and Positioning" IEEE Journal of Biomedical and Health Informatics, vol.PP, no.99, pp.1,1. download pdf. The article was featured as research highlight on JBHI.

2014. M. Altini, J. Penders, R. Vullers, O. Amft. "Automatic Heart Rate Normalization for Accurate Energy Expenditure Estimation: An Analysis of Activities of Daily Living and Heart Rate Features". accepted for publication in Methods of Information in Medicine. download pdf.
2014. M. Altini, M. van Dort, R. Vullers, C. van Hoof, O. Amft. "Self-Calibration of Walking Speed Estimations Using Smartphone Sensors". In ACOMORE, First Symposium on Activity and Context Modeling and Recognition 2014. download pdf.
2014. P. Casale, M. Altini, O. Amft. "Ensembles of Randomized Trees as Transfer Learning Mechanism in Body Sensor Networks". Accepted for BSN 2014. Nominee best paper award.

2013. M. Altini, J. Penders, O. Amft. "Personalizing Energy Expenditure Estimation Using a Cardiorespiratory Fitness Predicate". In: Pervasive Health 2013. download pdf. presentation. acceptance rate 32%.
2013. M. Altini, J. Penders, R. Vullers, O. Amft. "Combining Wearable Accelerometer and Physiological Data for Activity and Energy Expenditure Estimation". accepted for Wireless Health 2013. acceptance rate 21%. download pdf.
2013. S. Chen, M. Altini, J. Penders, O. Amft, J. Lach. "Unsupervised Activity Clustering to Estimate Energy Expenditure with a Single Body Sensor". In: BSN 2013. download pdf.
2013. M. Altini, J. Penders, O. Amft. "Body Weight-Normalized Energy Expenditure Estimation Using Combined Activity and Allometric Scaling Clustering". In: EMBC 2013. download pdf. presentation.
2013. M. Altini, J. Penders, R. Vullers, O. Amft. "Personalized Physical Activity Monitoring on the Move". accepted as demo paper for Wireless Health 2013. acceptance rate 21%. download pdf. Second place best demo award.
2013. R. Vullers, J. Penders, S. Brongersma, J. Wijsman, M. Altini, C.V. Hoof. "Wearable Smart Systems for Personal Healthcare and Lifestyle" SSI 2013.
2013. J. Penders, M. Altini, J. Wijsman, R. Vullers, C.V. Hoof. "Low-power wearable sensing for preventive healthcare" accepted as minisymposia for EMBC 2013.

2012. M. Altini, J. Penders, O. Amft. "Energy Expenditure Estimation Using Wearable Sensors: A New Methodology for Activity-Specific Models". In: Wireless Health. 2012. download pdf. presentation. acceptance rate 24%. Nominee best paper award.

Patents

2013. Application submitted: "Device and method for automatically normalizing the physiological signals of a living being"
2012. Application submitted: "Device and method for calculating cardiorespiratory fitness level and energy expenditure of a human being"

System integration (2009-2011)

Between 2009 and 2012 I worked on hardware, software and firmware design for Body Area Networks (BAN). I first developed the BAN interface to Android mobile phones (PCB design of the SDIO dongle, firmware implementation of the SDIO protocol on the MSP430, development of an application for ECG monitoring on Android). Then I worked on developing a reliable and optimized generic platform for rapid prototyping of BAN applications using sensor nodes combining off-the-shelf and imec’s components (Network protocol (MAC layer), drivers (SDIO, SD card and other peripherals) and algorithm implementation/optimization on the sensor nodes). During this period we also developed the first bluetooth low energy ECG patch.

Publications

2012. D. Buxi, S. Kim, N. van Helleputte, M. Altini, J. Wijsman, F. Yazicioglu, J. Penders, C. van Hoof, "Correlation Between Electrode-Tissue Impedance and Motion Artifact in Biopotential Recordings," Sensors Journal, IEEE , vol.12, no.12, pp.3373-3383, Dec. 2012.

2011. M. Altini, S. Polito, J. Penders, H. Kim, N. Van Helleputte, S. Kim and F. Yazicioglu. "An ECG patch combining a customized ultra-low-power ECG SoC with bluetooth low energy for long term ambulatory monitoring". In: Wireless Health. 2011. download pdf. Press release. Video. Second place best demo award.
2011. M. Altini, S. Del Din, S. Patel, S. Schachter, J. Penders, P. Bonato. "A low-power multi-modal body sensor network with application to epileptic seizure monitoring". Conf Proc IEEE Eng Med Biol Soc. 2011;2011:1806-9. download pdf.
2011. J. Penders, M. Altini, J. van de Molengraft, F. Yazicioglu, C. Van Hoof. "A Low-Power Wireless ECG Necklace for Reliable Cardiac Activity Monitoring On-The-Move". Invited paper for EMBC 2011. download pdf.
2011. M. Altini, E. Farella, M. Pirini, and L. Benini, "A Cost-effective Indoor Vibrotactile Navigation System for the Blind", in Proc. HEALTHINF, 2011, pp.477-481.
2011. S. Shrestha, T. Torfs, H. Kim, I. Romero, D. Buxi, T. Berset, M. Altini, F. Yazicioglu."Optimized R peak detection algorithm for ultra low power ECG system". IEEE BioCAS 2011.

2010. M. Altini, J. Penders, H.W. Roebbers: "An Android-based body area network gateway for mobile health applications". Wireless Health 2010: 188-189. download pdf. Press release. Video.
2010. M. Altini, D. Brunelli, E. Farella and L. Benini, "Bluetooth Indoor Localization with Multiple Neural Networks", International Symposium on Wireless Pervasive Computing, 2010.

academic Awards

2016 - Nominee Best Reviewer by the J-BHI editorial office.
2015 - PhD cum laude, Eindhoven University of Technology.
2014 - Nominee Best Paper Award at Body Sensor Networks 2014.
2013 - 2nd place Best Demo Award at Wireless Health 2013.
2012 - Nominee Best Paper Award at Wireless Health 2012.
2011 - 2nd place Best Demo Award at Wireless Health 2011.
2009 - Selected by the European Union in the first phase of the Vulcanus in Japan exchange program.