View source for Heart rate monitor

{{Short description|Personal monitoring device}}
{{About|the consumer device|the article about the medical device performing a similar function |Electrocardiography}}
{{Distinguish|pulse oximetry}}

[[File:FitbitIonicMomentDisplay.jpg|upright=1.3|thumb|Smartwatch displaying a reading of 92 beats per minute]]

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A '''heart rate monitor''' ('''HRM''') is a personal monitoring device that allows one to measure/display [[heart rate]] in real time or record the heart rate for later study. It is largely used to gather heart rate data while performing various types of [[physical exercise]]. Measuring electrical heart information is referred to as [[Electrocardiography|electrocardiography (ECG or EKG)]].

Medical heart rate monitoring used in hospitals is usually wired and usually multiple sensors are used. Portable medical units are referred to as a [[Holter monitor]]. Consumer heart rate monitors are designed for everyday use and do not use wires to connect.

==History==
Early models consisted of a monitoring box with a set of electrode leads which attached to the chest. The first wireless [[EKG]] heart rate monitor was invented in 1977 by [[Polar Electro]] as a training aid for the Finnish National Cross Country Ski team. As "intensity training" became a popular concept in athletic circles in the mid-80s, retail sales of wireless personal heart monitors started in 1983.<ref>{{cite book | veditors = Burke E |title=Precision Heart Rate Training |date=1998 |location=Champaign, IL |publisher=Human Kinetics  |isbn=978-0-88011-770-8}}</ref>

== Technologies ==
[[File:X-ray heart rate monitor sensor belt.jpg|thumb|250px|X-ray image of a chest strap (left: frontal view; right: side view). Visible is the circuit board, the antenna for data transfer, the battery and the connections to the electrodes in the adjoining belt at picture top and bottom.]]

Modern heart rate monitors commonly use one of two different methods to record heart signals (electrical and optical). Both types of signals can provide the same basic heart rate data, using fully automated algorithms to measure [[heart rate]], such as the [[Pan-Tompkins algorithm]].<ref name=PanTompkins>{{cite journal | vauthors = Pan J, Tompkins WJ | title = A real-time QRS detection algorithm | journal = IEEE Transactions on Bio-Medical Engineering | volume = 32 | issue = 3 | pages = 230–236 | date = March 1985 | pmid = 3997178 | doi = 10.1109/TBME.1985.325532 | s2cid = 14260358 }}</ref>

ECG ([[Electrocardiography]]) sensors measure the bio-potential generated by electrical signals that control the expansion and contraction of heart chambers, typically implemented in medical devices.

PPG ([[Photoplethysmogram|Photoplethysmography]]) sensors use light-based technology to measure the blood volume controlled by the heart's pumping action.

===Electrical===
The electrical monitors consist of two elements: a monitor/transmitter, which is worn on a chest strap, and a receiver. When a heartbeat is detected, a radio signal is transmitted, which the receiver uses to display/determine the current heart rate. This signal can be a simple radio pulse or a unique coded signal from the chest strap (such as [[Bluetooth]], [[ANT (network)|ANT]], or other low-power radio links). Newer technology prevents one user's receiver from using signals from other nearby transmitters (known as cross-talk interference) or [[eavesdropping]]. Note, that the older [[Polar Electro|Polar]] 5.1&nbsp;kHz [[radio transmission]] technology is usable underwater. Both Bluetooth and Ant+ use the 2.4&nbsp;GHz radio band, which cannot send signals underwater.

===Optical===
[[File:Welsh Government video - ETTF funding - Smart Phone Heart Rate Monitor, 2016.webm|thumb|[[Welsh Government]] video: a smart phone heart rate monitor, 2016]]
More recent devices use optics to measure heart rate by shining light from an [[LED]] through the skin and measuring how it scatters off blood vessels. In addition to measuring the heart rate, some devices using this technology are able to measure blood oxygen saturation ([[SpO2|SpO<sub>2</sub>]]). Some recent optical sensors can also transmit data as mentioned above.

Newer devices such as cell phones or watches can be used to display and/or collect the information. Some devices can simultaneously monitor heart rate, oxygen saturation, and other parameters. These may include sensors such as accelerometers, gyroscopes, and GPS to detect speed, location and distance.<ref>{{cite journal | vauthors = Lloret J, Sendra S, Ardid M, Rodrigues JJ | title = Underwater wireless sensor communications in the 2.4 GHz ISM frequency band | journal = Sensors | volume = 12 | issue = 4 | pages = 4237–4264 | date = 2012 | pmid = 22666029 | pmc = 3355409 | doi = 10.3390/s120404237 | bibcode = 2012Senso..12.4237L | doi-access = free }}</ref> In recent years, it has been common for [[smartwatch]]es to include heart rate monitors, which has greatly increased in popularity.<ref>{{cite journal | vauthors = Saygin D, Tabib T, Bittar HE, Valenzi E, Sembrat J, Chan SY, Rojas M, Lafyatis R | display-authors = 6 | title = Transcriptional profiling of lung cell populations in idiopathic pulmonary arterial hypertension | journal = Pulmonary Circulation | year = 2020 | volume = 10 | issue = 1 | pmid = 32166015 | doi = 10.1109/ISBB.2015.7344944 | pmc = 7052475 | s2cid = 10254964 }}</ref> Some smartwatches, smart bands and cell phones often use [[photoplethysmogram|PPG]] sensors.<ref>{{Cite web|url=https://www.theverge.com/23004703/heart-rate-ekg-smartwatch|title=How to measure heart rate on your smartwatch / Smartwatches have beefed up their heart health features in recent years|last=Song|first=Victoria |date=1 April 2022|website=The Verge|archive-url=|archive-date=|access-date=27 February 2024|df=dmy-all}}</ref>

===Fitness metrics===
[[Garmin]] (Venu Sq 2 and Lily*), [[Polar Electro]] (Polar H9, Polar H10, and [[Polar Electro#Current products|Polar Verity Sense]]),<ref>{{Cite web|url=https://www.techradar.com/reviews/polar-verity-sense|title=Polar Verity Sense review|last=Sawh|first=Michael |date=4 June 2021|website=techradar.com|archive-url=|archive-date=|access-date=27 February 2024|df=dmy-all}}</ref> [[Suunto]], [[Samsung Galaxy Watch]] ([[Samsung Galaxy Watch 5|Galaxy Watch 5]] and [[Samsung Galaxy Watch 6|Galaxy Watch 6*]]), [[Google]] ([[Google Pixel Watch 2|Pixel Watch 2*]]), Spade and Company, Vital Fitness Tracker**, [[Apple Watch]] (Series 7**, Series 9*, Apple Watch SE*, Apple Watch Ultra 2*), [[Mobvoi]] ([[Mobvoi#TicWatch_Pro_5|TicWatch Pro 5*]]) and [[Fitbit]] (Versa 3** and Versa 4*) are vendors selling consumer heart rate products. Most companies use their own proprietary heart rate algorithms.<ref>{{Cite web|url=https://www.pcmag.com/picks/the-best-smartwatches|title=The Best Smartwatches for 2024 (*Note: PC Magazine top 10 pick for 2024)|last1=Colon|first1=Alex|last2=Moscaritolo|first2=Angela|date=20 December 2023|website=pcmag.com|archive-url=|archive-date=|access-date=27 February 2024|df=dmy-all}}</ref><ref>{{Cite web|url=https://www.smartwatchreview.org/post/the-top-three-smartwatches-ranked-today?|title=The Top Three Smartwatches Ranked (**Note: smart watch review top 3 pick for 2022)|last=|first=|date=20 December 2023|website=smartwatchreview.org|archive-url=|archive-date=|access-date=27 February 2024|df=dmy-all}}</ref>

==Accuracy==
The newer, wrist based heart rate monitors have achieved almost identical levels of accuracy as their chest strap counterparts<ref name="pmid29881626">{{cite journal| author=Sartor F, Gelissen J, van Dinther R, Roovers D, Papini GB, Coppola G| title=Wrist-worn optical and chest strap heart rate comparison in a heterogeneous sample of healthy individuals and in coronary artery disease patients. | journal=BMC Sports Sci Med Rehabil | year= 2018 | volume= 10 | issue=  | pages= 10 | pmid=29881626 | doi=10.1186/s13102-018-0098-0 | doi-access=free | pmc=5984393 }} </ref> with independent tests showing up to 95% accuracy, but sometimes more than 30% error can persist for several minutes.<ref>{{cite web | vauthors = Haskins T | url = https://www.cardiocritic.com/chest-strap-vs-wrist-heart-rate-accuracy | title = Chest Strap Vs Wrist Based HR Accuracy | work = CardioCritic.com | date = 23 April 2022 }}</ref>{{Better source needed|reason=This is effectively medical information so a higher quality source would be preferable [[WP:MEDRS]]. Pls see note on talk.|date=September 2024}} Optical devices can be less accurate when used during vigorous activity,<ref>{{Cite web|url=http://neurosky.com/2015/01/ecg-vs-ppg-for-heart-rate-monitoring-which-is-best/|title=ECG vs PPG for Heart Rate Monitoring: Which is Best?| date = 28 January 2015 |website=neurosky.com|language=en-US|access-date=2018-11-28}}</ref> or when used underwater.

Currently, [[heart rate variability]] is less available on optical devices.<ref>{{cite web | vauthors =  Barnhart P | date = 21 March 2022 |title=Are Wrist Type Monitors Reliable? |url= https://allthestuff.com/wrist-heart-rate-monitor-accuracy/ | work = All The Stuff }}</ref> Apple introduced HRV data collection to the Apple Watch devices in 2018.<ref>{{Cite web | vauthors = Caldwell S |date= 26 March 2018|title=Heart Rate Variability (HRV): What is it, and why does Apple track it?|url=https://www.imore.com/heart-rate-variability-hrv-what-it-and-why-does-apple-watch-track-it|access-date=2022-01-24|website=iMore}}</ref> Fitbit started offering HRV monitoring on their devices starting from the Fitbit Sense, released in 2020.<ref>{{Cite web |title=A timeline and history of Fitbit |url=https://www.verizon.com/articles/Accessories/history-of-fitbit/ |access-date=2024-05-13 |website=verizon.com |language=en-US}}</ref>

=== Heart rate prediction ===
Heart rate prediction using machine learning has gained significant attention in health monitoring and sports performance research. Namazi et.al., 2025 evaluated various models including Long Short-Term Memory (LSTM), Physics-Informed Neural Networks (PINNs), and 1D Convolutional Neural Networks (1D CNNs), using physiological data such as heart rate (HR), breathing rate (BR), and RR intervals collected from wearable sensors during sports activities. The study introduced a hybrid approach combining Singular Spectrum Analysis (SSA) with these models to enhance predictive performance. Among the tested models, the SSA-LSTM method yielded the lowest prediction error, particularly when multivariate inputs (HR + BR + RR) were used. These findings support the use of AI-driven, multivariate prediction models for real-time cardiovascular monitoring in athletic and healthcare settings.<ref>{{Cite journal |last1=Namazi |first1=Asieh |last2=Modiri |first2=Ehsan |last3=Blesić |first3=Suzana |last4=Knežević |first4=Olivera M. |last5=Mirkov |first5=Dragan M. |date=2025-03-13 |title=Comparative Analysis of Machine Learning Techniques for Heart Rate Prediction Employing Wearable Sensor Data |journal=Sports |volume=13 |issue=3 |pages=87 |doi=10.3390/sports13030087 |doi-access=free |pmid=40137811 |pmc=11946376 }}</ref>

== See also ==
*[[Activity tracker]]
*[[Apple Watch]]
*[[E-textiles]]
*[[eHealth]]
*[[GPS watch]]
*[[Pedometer]]

== References ==
{{Reflist}}

== External links ==
*{{Commons-inline|Category:Heart rate monitors|Heart rate monitors}}
*[https://www.researchgate.net/publication/350621866_Visualization_of_ECG_recordings_using_Python_program_ECG-pyview/stats Visualization of ECG recordings using Python program ECG-pyview] A simple Python program visualizing raw data produced by chest strap based ECG sportesters. Enables to inspect ECG recordings having lengths up to days. ''(Open source, non-commercial use, use matplotlib.) A [https://www.researchgate.net/publication/350621769_Video_demonstrating_functions_of_Python_program_--_ECG-pyviewpy_--_that_is_visualizing_ECG_recordings demo video].''

[[Category:Biomedical engineering]]
[[Category:Diagnostic cardiology]]
[[Category:Exercise equipment]]
[[Category:Finnish inventions]]
[[Category:Medical monitoring equipment]]
[[Category:Physiological instruments]]