Personalized IoT-based Physical Activity Monitoring System for Heart Failure Patients (IoT-HFActive): Rationale and Methodological Protocol for a Randomized Clinical Trial

Globally, the prevalence of HF increases with age, affecting 1-2% of adults in developed countries. In Türkiye, more than one million HF cases were recorded in 2016, with a hospital admission rate of 2.5%, resulting in an estimated cost of 36.5 million TL to the healthcare system. By 2022, the prevalence of HF in Türkiye was reported to be 2.114%, representing approximately three million patients. Among younger individuals aged 18-50 years, the prevalence is 12% and the incidence is 0.3%, making Türkiye one of the countries with the highest burden of HF in younger populations. These statistics highlight the importance of risk management through lifestyle modifications and the promotion of physical activity, even among younger patients. Given the frequency of hospitalizations and the economic impact, HF represents a major public health concern in Türkiye, underscoring the need for greater involvement of healthcare professionals in providing support and self-management education for these patients.

In recent years, advances in pharmacological and device-based therapies for HF have improved survival and reduced hospitalization rates; however, overall health outcomes remain unsatisfactory. Both the progression of the disease and acute exacerbations negatively affect functional capacity and delay recovery. Reduced functional capacity is a typical finding in HF and is recognized as an indicator of poor prognosis and diminished quality of life. Following hospital discharge, symptoms such as fatigue, dyspnea, and edema contribute to exercise intolerance and limit daily activities. For this reason, improving functional capacity through regular physical activity, strengthening adherence to exercise, and reducing sedentary behaviors are considered essential goals in the management of HF. Regular physical activity enhances functional capacity, improves quality of life, and contributes positively to the pathophysiology of the disease. Nevertheless, the majority of patients remain prone to sedentary behavior, with fewer than half engaging in regular physical activity.

Recent studies have examined the factors that hinder physical activity and contribute to sedentary behavior in patients with HF. Physiological and psychosocial factors such as fatigue, shortness of breath, and lack of motivation make participation in and sustainability of exercise difficult. Although current HF guidelines strongly recommend exercise-based rehabilitation, barriers such as occupational responsibilities, transportation difficulties, costs, and geographic limitations restrict participation. In Türkiye, there has not yet been a comprehensive study addressing the reasons for insufficient physical activity in this patient group. Existing research has mainly focused on exercise intolerance and limitations in daily activities. On the other hand, home-based or community-based exercise and physical activity programs are being proposed as strong alternatives to center-based rehabilitation. These programs, through regular monitoring and personalized motivational support, can improve adherence and promote both physical and psychosocial recovery. Technologically supported approaches, in particular, provide effective outcomes through personalized interventions tailored to individual needs. Systematic reviews indicate that home-based rehabilitation supported by wearable sensors may be as effective as center-based approaches while also improving adherence. Moreover, interventions such as tele-rehabilitation and exergaming, when combined with behavioral strategies, have further contributed to improvements in adherence. Nevertheless, the lack of personalized technology-based solutions tailored to individual needs remains a limitation to success. Our proposed project aims to fill this gap by offering a personalized, technology-assisted physical activity intervention that supports both physical and psychosocial recovery in patients with HF.

Traditional exercise protocols have shown beneficial effects on functional capacity and health parameters in HF patients, but these protocols are generally not adapted to individual health conditions. Exercise adherence, defined as the extent to which individuals follow the recommended frequency, duration, and intensity of exercise, is a key factor in HF management. When standardized protocols fail to meet individual needs, adherence may be moderate in the early months but tends to decline over time. Adherence becomes even more challenging when physical activity goals are not individualized according to heart rate reserve. From a patient-centered perspective, tailoring exercise in terms of type, intensity, duration, frequency, and personal needs is considered essential for effectively promoting adherence. However, studies have consistently shown that adherence to exercise programs among HF patients is lower than expected. For example, adherence rates in large-scale trials have ranged between one-third and one-half of participants, with completion rates often falling below 50%. These findings confirm that fewer than half of HF patients engage in regular physical activity. Therefore, individualized and technology-assisted interventions are urgently needed to improve adherence and support sustained participation in physical activity.

Technological opportunities hold great potential for improving physical activity in patients with HF. Wearable smart devices and mobile applications enable real-time monitoring of health data, offering more dynamic and personalized solutions compared with traditional exercise methods. These technologies allow patients to monitor their health status at home, optimize their physical activity, and provide real-time feedback to healthcare professionals. Mobile applications have been developed to track step counts and sedentary behaviors in order to enhance activity levels in HF patients, while others have focused on supporting self-care behaviors without directly monitoring exercise parameters. Some digital health tools have integrated monitoring of metrics such as step count and heart rate to better tailor activity goals. However, most studies to date have been short-term, highlighting the need for further research on sustaining long-term motivation and effectiveness. Earlier applications were often limited to pedometer-based activity tracking or focused primarily on the acceptability of mobile technology after cardiac rehabilitation. While many studies have emphasized step counts and walking distance as the main indicators of activity, recent evidence suggests that combining these with more in-depth biological data, such as heart rate and energy expenditure, may provide a more comprehensive and physiologically grounded assessment in HF patients.