Currently, nearly 6 in 10 US adults are suffering from at least one chronic condition (Groenendaal et al., 2021). Chronic diseases are considered a major challenge for the global health system. Noncommunicable diseases (NCDs), such as cardiovascular disease, chronic respiratory diseases, cancer, and diabetes, are a leading cause of morbidity and disability. In 2015, it was estimated that 2.3 billion people worldwide would be suffering from a chronic disease. In the United States, around half the population is suffering from one or more chronic diseases. Chronic diseases account for 86% of the total health care costs in the United States. As a consequence of the increasing prevalence of chronic diseases, health care costs are expected to rise further. Some main aspects attributing to high health care costs are emergency room visits and hospitalizations resulting from acute exacerbations in chronic diseases. Several studies have indicated that more frequent monitoring, especially of vital signs, could lead to an early detection of exacerbations. Continuous or frequent monitoring could play a role in managing patients suffering from chronic diseases. Wearable sensor technology, possibly combined with artificial intelligence (AI), provide this type of monitoring.
1. Introduction to Wearable Health Technology
Chronic diseases are a major public health concern around the world (Bonacaro & Sookhoo, 2018). Many recent technologies address the need for low-cost and affordable monitoring systems that can be integrated into daily practice. Moreover, the integration of advanced technologies in healthcare is demonstrated in many clinical studies. Various wearable devices are currently available to monitor and keep records of different clinical information with the aim of helping users, both chronic patients and healthy individuals, improve their quality of life. Some wearable devices have been proved to prevent hospital re-admissions and to treat effectively life-threatening conditions. Many studies have demonstrated that monitoring vital signs, such as heart rate and respiratory rate, can be an accurate means for monitoring chronic patients’ health. Higher level of acceptability and usability are achieved when users are involved in the testing stage prior to the release of the device and/or the features and terms of use are clearly described to patients and carers. Wearable devices are also proved to be more accurate than clinical assessment in estimating the risk of falls in chronic patients, thus improving safety in the home care setting. The limited availability of commercial devices, a potential lack of understanding and competence in the use of technologies and software, especially for elderly or non-tech-savvy patients, and data safety are issues to be addressed in order to facilitate the integration of devices into clinical practice. More studies need to be undertaken to understand how these useful technologies can be integrated into healthcare system, and how clinical data can be flawlessly shared among patients and healthcare professionals.
1.1. Definition and Types of Wearable Health Tech
Wearable health technology, also known as wearable health monitoring technology, encompasses a range of devices capable of collecting real-time information about a patient’s health and transmitting it to a receiver via the internet (Groenendaal et al., 2021). These devices typically consist of biosensors that are incorporated into wearable materials or implants. Common examples include smart watches equipped with heart rate monitors and textile-integrated health monitors that measure bioelectrical signals. By connecting these sensors to a smartwatch or smartphone, the received information can be processed and transmitted to a doctor or healthcare provider. Along with wearable cameras or microphones, wearable health monitoring technology falls under the broader category of “wearable technology.
A wide variety of wearable health monitoring devices are currently available on the market. These devices mostly fall into two main categories: smart watches or fitness trackers, and clothing that incorporates bio-sensors. Smart watches and fitness trackers are wrist-worn devices capable of collecting biometric information like heart rate and exercise levels. Based on this data, these devices can assess physical activity and various health parameters, including the monitoring of stress, sleep quality, and heart rate (L. Scheid et al., 2023). Although some differences exist regarding the measured parameters, the resulting data from each device is used by its respective mobile application to create user-friendly visualizations and health estimates. Automatic monitoring of daily physical activity and health parameters allows for goal setting and tracking changes over time, promoting more healthy behavior and lifestyle choices.
2. Chronic Conditions and Their Monitoring
Chronic diseases are one of the main challenges to the global health system, accounting for tremendous social and economic burdens. Approximately half of the overall population in the United States is suffering from one or more chronic diseases. This number continues to grow, fueled, among others, by the aging population, the new lifestyle epidemics (e.g. obesity), and the COVID-19 pandemic. Chronic diseases account for 86% of the total health care costs in the United States, which is around 3 trillion each year. This is a massive amount of 8330 dollars per person (Groenendaal et al., 2021). Some of the main aspects attributing to these high health care costs are the increase of sick, costly patients, the emergency room visits, and the hospitalizations resulting from acute exacerbations. In chronic diseases such as chronic obstructive pulmonary disease (COPD), asthma, heart failure, chronic kidney disease, and even early diabetes, the gradual worsening of the disease can be detected after the analysis of complex data derived from multiple biosignals. Unfortunately, this data is frequently not taken into account in current care settings because it is simply too complex and cumbersome or too time-consuming to collect, analyze, and interpret. Outside the hospital, this data is hardly collected at all (Guo et al., 2021). Most of the measurements are periodic and are executed manually by the patient. These measurements occur too infrequent to monitor the progression of the disease or the response to treatment within a timeframe that is suitable for the ever-increasing number of patients needing the treatment. On the other hand, these measurements are too static in time and in value to capture a full view of the patient’s condition accurately.
Unfortunately, there is currently no wearable technology that would make this possible. Wearable technology could greatly help in controlling this growing cost by remote monitoring of these patients and therefore earlier detection of disease worsening and timely intervention. In this way, many emergency visits and hospitalizations can be avoided. Wearable sensor technology, possibly combined with artificial intelligence (AI), is one of the techniques that provides this type of monitoring for today’s chronic diseases. One promising sensor technique for wearable monitoring of chronic disease is bioimpedance. Bioimpedance is a noninvasive, versatile sensor method applied to extract a wide range of health care parameters. With bioimpedance, time-varying signals can be obtained such as respiration, cardiac output, and bioimpedance topographic and spectroscopic analysis can be used for continuous, real-time imaging of tissue perfusion and monitoring of fluid balance. All of these parameters are of great importance for an accurate assessment of health conditions involving the cardiovascular, pulmonary, renal, and metabolic system.
2.1. Common Chronic Conditions
A chronic condition is one that lasts for a year or more and requires ongoing medical attention or limits activities of daily living, or both. Common chronic conditions include depression, arthritis, asthma, cancer, chronic obstructive pulmonary disease (COPD), chronic kidney disease, diabetes, heart disease, obesity, osteoporosis, and stroke. There are several chronic conditions that are often required to be continuously monitored. These chronic conditions are discussed in detail below. To avoid repetition, the explanation related to the common chronic conditions is taken from (Guo et al., 2021) ; (Groenendaal et al., 2021).
Cardiovascular Diseases (CVDs): CVDs are the most common chronic diseases, which mainly include coronary heart disease, heart failure and cerebrovascular disease. According to WHO statistics, approximately 18 million people died from related diseases in 2019, accounting for 32% of global mortality. In addition, CVDs are also one of the leading causes of economic burdens among chronic diseases. It was estimated that the total economic burden of CVDs in the US was $228.4 billion in 2010, which had continuous growth trends in later years, and the projection would be $368.9 billion in 2030. This is because it normally costs large amounts during the early phase of attention after symptoms raise alarming changes. Other than academic consideration, the willingness from renowned companies such as Apple, Google and Fitbit also significantly promotes the development of wearable technology.
Wearable Health Monitoring: Wearable health monitoring focusing on chronic diseases has received increasing attention in research and application fields since 2015. The chronic diseases mainly detectable by these devices/algorithms include cardiovascular diseases (CVD), diabetes and other metabolic diseases, respiratory system diseases, body temperature related illnesses and other involuntary diseases such as cancer.
2.2. Importance of Continuous Monitoring
Currently, nearly 6 in 10 US adults are suffering from at least one chronic condition. Not only do these chronic conditions impose a major burden on people’s lives and wellbeing, but they also have a dramatic impact on the health care system. This group of diseases is responsible for 86% of total health care costs in the US, among which heart diseases and cancer are the most costly conditions. Some aspects attributing to these high health care costs are emergency room visits and hospitalizations resulting from acute exacerbations in chronic diseases. In recent decades, technological improvements in sensor and communication technology have resulted in the dissemination of wearable devices and a significant boost in mobile health (mHealth) applications. Recent studies have shown that more frequent monitoring could lead to early detection of exacerbations, such as in heart failure and in asthma. By providing monitored patients’ data to health care professionals, wearable sensor technology, possibly combined with artificial intelligence (AI), could thus be helpful in the timely and preventive management of chronic diseases (Groenendaal et al., 2021).
New sensor technologies allow the creation of smart textiles in which textile electrodes can be incorporated to monitor physiological signals. Textile electrodes can be used to monitor bioelectrical signals such as ECG, EEG, and EMG. The soft and flexible textile electrodes can adhere well to skin and provide reliable signal quality that resembles that of conventional electrodes. Wearable monitoring systems can be used in a variety of applications, ranging from daily lifestyle monitoring and health monitoring in healthy subjects to monitoring patients with chronic conditions. Monitoring patients with chronic conditions could help in early detection of disease worsening and, hence, a reduction of health care costs. One of the chronic conditions for which wearable systems could be highly beneficial is the chronic respiratory condition. The current standard for monitoring these patients is intermittent clinic visits (Viderman et al., 2022).
3. Benefits and Limitations of Wearable Health Tech
Wearable health technology offers numerous benefits for monitoring chronic conditions. It serves as a personalized health monitor, providing prevention and detection services by continuously measuring health-related variables, including those affecting understanding and management of chronic health conditions like hypertension and heart diseases. Currently, continuous health monitoring involving actigraphy for assessing physical activity and sleep patterns is widespread, allowing precise determination of lifestyle changes and adherence to health protocols. As research progresses, efforts are being made to develop smart clothing with embedded sensors to provide continuous heart monitoring, temperature measurement, and seizure detection. Wearable devices have also been used for other purposes, including assessing the risk of chronic health disorders, safety, and chronic health condition management. In addition to physical parameters, wearable devices capable of measuring parameters related to lifestyle, such as residence time and exposure to environmental hazards, have been designed. However, several limitations hinder the effective use of wearable devices for controlling chronic conditions. Consumer-level wearable devices can monitor heart rate but fail to classify cardiac arrhythmias accurately. Wearable devices, in general, have low awareness and consideration among the elderly (L. Scheid et al., 2023). Wearable devices used for chronic health condition management typically focus on monitoring only one health parameter. Industrial-grade wearable devices come with high costs and require extensive infrastructure. There is a lack of primary health monitoring wearables and a national network for continuous epidemiological studies. The society is also exposed to privacy and security issues, which excessive use of wearable devices may introduce.
3.1. Advantages of Wearable Health Tech
Wearable health technology could have a significant impact on controlling health care costs. Both the national health service as well as private insurance companies are under pressure to decrease costs associated with growing healthcare expenses. One option is to control the costs by remote monitoring of patients and early detection of disease worsening, especially mild or moderate changes (Groenendaal et al., 2021). Wearable health technology is currently advancing rapidly. A wide variety of commercial wearable applications have been developed, including vital sign monitoring wearables such as ECG and heart rate monitoring watches, wrist actigraphy sensors used to estimate sleep quality, pedometers for step counting, wearables to estimate energy expenditure from heart rate monitoring or activity level, body-temperature measurement wristbands, weight and waist measurement scales with accompanying smartphone applications, and photoplethysmogram-based pulse oximeter watch monitoring peripheral oxygen saturation. Most currently available solutions focus on lifestyle monitoring and have already shown great potential to improve lifestyle and compliance by increasing awareness. Some earlier solutions are promising for early detection of disease changes (e.g., deterioration of heart failure), which could prevent hospitalization. Detection of diminishing health, sudden adverse events, overload, or decrease in performance could positively affect the patient or user’s well-being and safety by taking preventive actions (e.g., adjustment of medication, change in activity level, or timely evacuation).
Wearable health technology comprises a wide range of devices and sensors for measurement purposes, which can be worn, often on the human body. Wearable sensors have great promise for the continuous and real-time monitoring of chronic disease by measuring health care parameters (e.g., vital signs, clinical symptoms, or lifestyle). One of the most important reasons to advance wearable health technology is the high and growing burden of chronic diseases on society and the global health system. For example, chronic diseases are responsible for 71% of all global deaths, with cardiovascular diseases as the leading cause. There is a growing demand for alternative, remote monitoring, and treatment strategies outside the hospital that are less labor-intensive and more effective (e.g., outpatient surveillance).
3.2. Challenges and Limitations
The analysis is divided into two main subsections. The first subsection presents the potential applications and benefits of wearable health technology in the context of chronic conditions. These include proactive and early risk detection, improved doctor-patient relationships, data control, continuous patient monitoring, less intrusive assessment, compliance with medical guidance, data anonymity, customization to individual needs, and positive effects on patients’ mental health. Through this discussion, readers are encouraged to consider and appreciate the manifold advantages of integrating this technology in managing chronic conditions. Conversely, the challenges and limitations subsection outlines the obstacles and constraints that accompany the integration of wearable health technology in chronic condition management. It discusses issues such as data safety and privacy concerns, natural barriers to adoption, the availability of data and technology, accessibility issues, the reliability and validity of devices, data overload, and integration into health systems. By acknowledging these factors, readers can develop a more nuanced understanding of the complexities involved in leveraging wearable devices for healthcare. The discussion on wearable health tech challenges aims to address potential concerns and barriers associated with the implementation of this technology.
4. Key Features and Technologies in Wearable Health Devices
Overview of Wearable Health Devices Wearable health devices support a wide variety of chronic health monitoring with multiple personalized health parameters to provide real-time awareness of the chronic health status (i.e., patient health status during chronic conditions). Patient awareness of chronic health status is the very first step toward chronic health management. Chronic health conditions evolve gradually; monitoring physiological parameters is essential to track the underlying physiological processes. Wearable health devices allow unobtrusive and non-invasive chronic health monitoring, thus ensuring continuous monitoring.
Essential Features in Wearable Health Devices Wearable health devices are typically designed to be small form factor, light-weight, and low-power devices to conform to the wearability needs. The form factor of wearable health devices can vary from a wristwatch-like form factor (smartwatches) to a cloth tag-like form factor (wearable patches). However, the basic functionalities are similar in wearable health devices. Wearable health devices typically have bio-sensors as the main component, which transduces the physiological parameters into electrical signals (voltage or current). These bio-signals are subsequently processed and transmitted to external devices such as smartphones or cloud data servers for further processing and chronic health status reconstruction (Groenendaal et al., 2021).
4.1. Sensors and Data Collection
The sensors and data collection form the core components of wearable health technology. Sensors can be used to gather health- or fitness-related data regarding body conditions. Different varieties of sensors have different mechanisms for data collection. Based on the specific physiological measurements, commercially available wearable health monitoring devices can be categorized into devices that measure temperature, motion and inertial, blood pressure, heart and blood oxygen, glucose, biochemical, and others. According to the signal processing methods of data collection, portable health monitoring can be classified into continuous monitoring, periodical (on-demand/spot-check) monitoring, and immediate monitoring (Guo et al., 2021). Understanding sensor and data collection helps comprehend the mechanism of continuous health monitoring and the development of wearables.
Wearable bioimpedance (a small -mmac to kHz-ac signal powered by small battery) monitoring is a non-invasive, versatile sensing method and has the potential to monitor many diseases at a lower cost compared to the current gold standards (Lab-on-a-chip and miniaturization technologies) (Groenendaal et al., 2021). Abnormalities in the physiological state induce changes in the body’s impedance spectrum, which provides a measure of its dielectric properties. The dielectric properties reflect biological and physiological characteristics of the considered tissue/s (e.g., species, morphology, shape, charge, density, viscosity, ion mobility, volume distribution, arrangement; temperature changes, blood flow, extracellular fluid build-up) and can be exploited as an effective tool to characterize both normal and diseased conditions.
4.2. Wireless Connectivity
Wireless connectivity focuses on the methods and technologies with which health data transmission from the wearable device to an external (telemetry) system occurs. This subject bleeds into other design aspects, such as radio transmission choice, bandwidth, and sampling frequency, and if relevant, these aspects are included. By reading this section, the reader can gain knowledge about the essential design aspects of the transmission mechanism of health data from wearable devices to external systems. Whether the monitoring is continuous, near-continuous, or discontinuous, transmission in real-time or in batch mode, and if relevant, data compression schemes to meet bandwidth requirements: this is all part of health data transmission. Hence, although the intention was to focus purely on data transmission, in practice, there is overlap with other aspects of wireless connectivity. The role of connectivity in wearable health devices is essential for preventing isolation of the monitoring system. The benefit of monitoring vital signs with wearable devices is only real when information on the health status of the monitored person is available remotely. Regularly, summary indices or batch values corresponding to a time interval can be sent to the telemetry system without a need for continuous connectivity (Wan An et al., 2017). Wireless bioimpedance measurement was identified as the most promising approach to integrate multiple bioimpedance sensors into a complete mobile health device. However, for wearable devices, rigid antennas cannot be used due to hygiene, comfort, aesthetics, and portability issues. Currently, there is a lack of reliable antennas for compact wearable devices, which was presented as one of the most important challenges to be resolved for the further development of wearable monitoring devices (Groenendaal et al., 2021).
5. Data Privacy and Security in Wearable Health Tech
The rise of wearables and the Internet of Things (IoT) has transformed a variety of applications, from fitness tracking to chronic condition monitoring, smart homes to smart cities, and contact tracing to lifestyle medicine. Such internet-enabled sensors gather massive amounts of user data. Such huge amounts of user data should be anonymized, encrypted, and protected from being breached. In wearables, the concern about privacy control strongly increases, as sensors provide real-time insight into users’ personal data. Such data puts at risk sensitive data on one’s health, social status, and psychology, and would therefore provide fertile grounds for different kinds of discrimination by third parties, from insurance companies to employers (Ayers, 2018). Smartphones as wearables heighten this concern, as they are literally constantly on and provide much more data than needed for the wearables. Due to this context, stakeholders in such industries need to consider privacy from the outset of product design through to end-of-life.
Wearables do not decrease industries’ power by the mere fact that users have unprecedented control over their data. Users need to bear a personal financial burden when monitoring their own data set in a smart home installation. Thus, the one who involves in continued data generation and investment in a future smart home is a fraud victim if later the permissions are rescinded. When granted, however, such sensitive data allows for an unprecedented influence over one’s life, social groups, lifestyle and purchases. With the help of machine learning algorithms, this data provide fertile ground for profiling and discriminating users, and in the worst case predicting the likelihood of health conditions and future behaviour. Such personal insights, coupled with a race between insurance companies and health tracking wearables for cooperation, have big implications how and whether one is granted insurance.
6. Integration of Wearable Health Tech in Healthcare Systems
This section focuses on the integration of wearable health technology into healthcare systems, exploring the implications and challenges of including wearable health technology in existing systems. Specific attention is given to the sensors and wearable health technology needed by healthcare systems to work with patient devices. The system approach clearly delineates the essential factors and actors involved in integration, uncovering unknown aspects of the communication between wearables in patients’ hands and care providers. The integration aspect is crucial for readers to gauge the transformative power of wearable health technology in healthcare delivery redesign (Groenendaal et al., 2021).
Two challenges in integration already in the 2020–2030 time frame are underlined: standardization of data formats and communication protocols between sensor types, and lack of interoperability between the platforms of vendors and service providers of wearables. Although it is unclear how long time large vendors will control the market, both challenges will likely need involvement from national or global authorities due to their magnitude and complexity. Fortunately, there are positive movements in cooperation between care providers and vendors, but further action is needed to guarantee patient benefits (Bonacaro & Sookhoo, 2018). The section ends with a summary of opportunities and options to be on time with the arrival of disruptive technology.
7. Case Studies and Success Stories in Monitoring Chronic Conditions
Focusing on practical applications, this section presents case studies and success stories that illustrate the successful use of wearable health technology in monitoring chronic conditions. By exploring these cases, readers can gain insights into the real-world results and advantages of utilizing wearable devices for healthcare purposes. From heart rate and blood pressure monitors to smartwatches with ECG capabilities, a plethora of wearable health technologies are currently being employed to track various health metrics (Groenendaal et al., 2021). The majority of these devices fall under the umbrella of fitness wearables, designed primarily for consumer use, with healthcare applications primarily being pursued in research contexts. Nevertheless, there have been significant advancements in efforts to move research prototypes, encompassing wearable sensors, software apps, and cloud-based analytics, into practice. Compelling instances of successful wearable health technology deployment in the management of chronic conditions are highlighted.
Wearable Bioimpedance Monitoring technologies have been utilized for monitoring Chronic Conditions. In the United States, nearly 6 in 10 adults have chronic conditions, such as heart failure or diabetes, which could benefit from accessible monitoring. Wearable technology allows for the remote monitoring of such conditions, curbing costs through early disease worsening detection. Bioimpedance is a noninvasive technique that can monitor many health care parameters relevant to chronic conditions. There has been a focus on dedicated devices for cardiac output monitoring, impedance cardiography-based respiration rate and effort, and devices that use bioimpedance methods to control weight and assess fluid status. Wearable bioimpedance monitoring of chronic conditions is evaluated, with emphasis on the current status, recent advances, and challenges. Additionally, wearable cardiac output monitoring, including novel configurations tailored to activity monitoring and long-term wearability, is addressed.
8. Future Trends and Innovations in Wearable Health Technology
From monitoring underlying health conditions like cardiovascular disease and diabetes to tracking falls in the elderly, wearable technology is changing how individuals manage their health. Chronic health conditions are generally longer-duration conditions that require lifelong management and care. Wearable technology could help control rising health care costs by enabling remote monitoring of patients, making it easier to detect when a patient’s condition is worsening. Bioimpedance is one of the more promising sensor techniques for wearable monitoring of a chronic disease. Bioimpedance is a noninvasive and versatile sensing technology that can be applied to a wide range of health care parameters (Groenendaal et al., 2021). External electrodes and an external signal processing unit are necessary. Changing field patterns will induce conformational and spatial changes randomly in biological tissues. These time-varying signals can be analyzed to extract a variety of signals such as respiration and cardiac output. Body composition and fluid status monitoring is another area of application for bioimpedance, e.g., pulmonary congestion monitoring in heart failure patients. More recently, wearable continuous bioimpedance monitoring during mechanical ventilation has gained interest. This Perspective outlines the use of wearable bioimpedance monitoring for chronic conditions, focusing on its current status, recent improvements, and challenges ahead.
9. Conclusion and Implications for the Future
The implications of wearable health technology in monitoring chronic conditions have been discussed. Beginning with the potential of this technology on people with chronic conditions and subsequently moving through the technology’s use and research avenues, it becomes apparent that this technology has already been addressed on several levels and that there are still many knowledge gaps. Further investigation into people’s acceptability and adherence to this technology could provide more insight into conditions affecting monitoring itself rather than the sensor devices. Acceptance or rejection by key groups such as health insurance providers or doctors is another area that should not be ignored.
It can further be noted that the applications that significantly impact industries outside of health care are often developed very quickly, resulting in a wide diversity of products. With wearables related to healthcare, this industry is starting to move relatively late, but among the diverse range of products already available for general use, vital signs and general activity monitoring seem to have gained the most visibility (Groenendaal et al., 2021).
References:
Groenendaal, W., Lee, S., & van Hoof, C., 2021. Wearable Bioimpedance Monitoring: Viewpoint for Application in Chronic Conditions. ncbi.nlm.nih.gov
Bonacaro, A. & Sookhoo, D., 2018. Chronic Conditions and Wearable Devices: Does the Use of Modern Technologies Improve Quality of Life in Chronic Patients. [PDF]
L. Scheid, J., L. Reed, J., & L. West, S., 2023. Commentary: Is Wearable Fitness Technology a Medically Approved Device? Yes and No. ncbi.nlm.nih.gov
Guo, Y., Liu, X., Peng, S., Jiang, X., Xu, K., Chen, C., Wang, Z., Dai, C., & Chen, W., 2021. A review of wearable and unobtrusive sensing technologies for chronic disease management. ncbi.nlm.nih.gov
Viderman, D., Seri, E., Aubakirova, M., Abdildin, Y., Badenes, R., & Bilotta, F., 2022. Remote Monitoring of Chronic Critically Ill Patients after Hospital Discharge: A Systematic Review. ncbi.nlm.nih.gov
Wan An, B., Hwal Shin, J., Kim, S. Y., Kim, J., Ji, S., Park, J., Lee, Y., Jang, J., Park, Y. G., Cho, E., Jo, S., & Park, J. U., 2017. Smart Sensor Systems for Wearable Electronic Devices. ncbi.nlm.nih.gov
Ayers, T., 2018. Self-Regulation within the Wearable Device Industry and The Alignment to Device Users’ Perceptions of Health Data Privacy. [PDF]