Mobile Application to Improve Physical Activity in Patients With Heart Failure

Heart failure (HF) is a chronic and progressive clinical condition that significantly affects patients' functional capacity, daily activities, and quality of life. Physical inactivity and sedentary behavior are common among individuals with HF and may contribute to further deterioration in functional capacity and overall health status. Regular physical activity is an important component of HF management and is recommended to improve exercise capacity, reduce symptoms, and support patients' ability to maintain daily activities. However, despite the established benefits of physical activity, many patients with HF experience difficulties initiating and maintaining regular physical activity due to symptoms, reduced exercise tolerance, lack of motivation, and insufficient monitoring and support.

In recent years, mobile health technologies and wearable devices have provided new opportunities for supporting physical activity in individuals with chronic diseases. Mobile applications integrated with wearable devices can facilitate continuous monitoring of physical activity and heart rate, provide individualized feedback, support goal setting, and deliver educational and motivational content. These features may help individuals become more aware of their activity patterns, monitor their progress, and develop sustainable physical activity habits. In patients with HF, technology-supported monitoring may also facilitate the identification of periods of reduced activity and provide opportunities for timely communication and support.

This study aims to evaluate the effect of a mobile application integrated with smart wristbands on physical activity behavior in patients with HF. The intervention is designed to support physical activity through individualized exercise goals, heart rate monitoring, visual feedback, educational videos, and motivational messages. The study will also evaluate changes in health-related quality of life following the intervention.

Study Design and Setting

This study is designed as a single-blind, randomized controlled intervention study with two parallel groups: an intervention group and a control group. Participants will be randomly assigned to the groups in a 1:1 ratio. The study will be conducted between December 01, 2026, and March 15, 2027, among patients with HF followed in the cardiology outpatient clinics of İzzet Baysal Education and Research Hospital, Bolu, Türkiye.

Study Population

The study population will consist of individuals diagnosed with HF who attend the cardiology outpatient clinics of the study hospital. Patients who meet the inclusion criteria and agree to participate voluntarily will be enrolled in the study.

The inclusion criteria are:

• Having a diagnosis of HF confirmed by echocardiography.
• Having heart failure with reduced ejection fraction (HFrEF).
• Being between 18 and 75 years of age.
• Being classified as New York Heart Association (NYHA) functional class I, II, or III.
• Having no ischemic findings on coronary angiography performed within the previous three months.
• Having no physical limitations that prevent participation in physical activity.
• Obtaining a score of 25 or higher on the Standardized Mini-Mental State Examination.
• Owning a smartphone compatible with the mobile application.

The exclusion criteria are:

• Being younger than 18 or older than 75 years of age.
• Having an ischemic lesion requiring revascularization on coronary angiography.
• Having undergone major cardiac surgery within the previous three months.
• Experiencing worsening dyspnea or exercise intolerance at rest.
• Having uncontrolled arrhythmia.
• Having uncontrolled diabetes (HbA1c ≥ 7).
• Having chronic pulmonary disease or renal failure.
• Having symptomatic postural hypotension.
• Having an Edmonton Frail Scale score of 9 or higher, indicating moderate-to-severe frailty.
• Having a neuropsychiatric disorder that severely affects cognitive functions such as attention, memory, and comprehension, including dementia or Alzheimer's disease.
• Being unwilling to participate in the study.

Intervention Group

Participants assigned to the intervention group will receive a mobile application-supported physical activity monitoring intervention integrated with commercially available smart wristbands. The intervention will include supervised exercise sessions, individualized heart rate monitoring, physical activity goal setting, visual feedback, educational content, and motivational messages.

1. Initial Education and Supervised Exercise Sessions

   At the beginning of the intervention, participants will receive an individual face-to-face training session covering the importance of physical activity in HF, practical recommendations for increasing daily activity, and precautions to be considered before, during, and after physical activity. The educational content will be prepared based on evidence-based scientific sources.

   Following group allocation, participants in the intervention group will attend supervised exercise sessions for one month. These sessions will be conducted three days per week, with each session lasting approximately 50 minutes, under the supervision of an expert physiotherapist.

   During these sessions, participants will be provided with smart wristbands, and the mobile application will be installed on their smartphones. They will receive practical training on how to use the wristbands and application.

   The supervised exercise sessions will serve three main purposes. First, heart rate data will be collected simultaneously through the smart wristbands during exercise sessions. At the end of the one-month supervised period, the average heart rate expected to be reached during exercise or physical activity will be calculated for each participant. This individualized target heart rate will subsequently be displayed on the application's home screen.

   Second, participants will be introduced to basic exercises that can be performed independently at home, particularly under unfavorable weather conditions or when outdoor physical activity is not feasible. These exercises will be demonstrated by the expert physiotherapist, recorded as videos, and uploaded to the application's video section.

   Third, participants' exercise tolerance and the occurrence of potential adverse events will be monitored throughout the supervised exercise period. Observational notes regarding participants' experiences during the sessions will be recorded using a follow-up chart.

2. Mobile Application Components

The mobile application is designed to support participants in monitoring their physical activity, tracking their progress toward individualized goals, and maintaining regular physical activity behaviors. The application consists of three main screens: the home screen, messages screen, and videos screen.

Home Screen

The home screen includes sections for monitoring physical activity goals, exercise duration, and heart rate data.

Physical activity goals: Participants will be able to view their weekly and monthly physical activity goals. The weekly goal will be set at 150 minutes and the monthly goal at 600 minutes. Participants will be able to monitor their completed activity duration, the remaining time required to reach their goals, and their progress toward the established targets. Changes in physical activity levels and progress toward monthly goals will also be presented through graphical visualizations.

Daily activity confirmation: At 21:00 each day, participants will receive a notification on their smartphones. When they select the notification, they will be directed to the application's home screen, where their activity duration within the target heart rate range will be displayed. For example, the application may display a message such as, "We see that you stayed active for 44 minutes today. Do you confirm?" Participants will be asked to confirm the reported duration. If they have not exercised, they can select the "I did not exercise" option. If their heart rate increased due to a medical condition rather than physical activity, they can select the "I did not exercise because I was feeling unwell" option. This confirmation process will help distinguish physical activity from heart rate increases associated with other health conditions. Participants reporting that they feel unwell may be contacted by telephone for further follow-up.

Heart rate monitoring: Heart rate data obtained from the smart wristband will be displayed on the home screen. Participants will be able to view their heart rate values, compare them with their individually determined target heart rate, and monitor changes through graphical representations. This feature is intended to support participants in monitoring their heart rate during physical activity and performing activities within their individually defined safe limits.

Messages Screen

The messages screen will provide educational, informative, and motivational messages to encourage regular physical activity. Messages will be designed to increase participants' awareness of the benefits of physical activity, support motivation, and encourage the development and maintenance of regular exercise habits.

In addition to routine motivational messages, individualized feedback will be provided to participants who do not regularly confirm their daily activity or who fail to achieve their weekly and monthly exercise goals. Weekly and monthly messages will be used to encourage participants to resume or maintain their physical activity behaviors.

Examples of messages include:

"Remember, small steps make a big difference! Walk an extra 10 minutes today."

"Moving is the best gift for your heart. Come on, let's take some steps!"

"Sitting for long periods can negatively affect your heart health. Now it is time for a short break and stretching."

"Every step brings you closer to a stronger heart. Come on, let's take some steps!"

"Being active today is the key to feeling more energetic tomorrow. Let's start!"

"We noticed that you haven't been active enough this week! How about protecting your heart health with regular physical activity?"

"Congratulations, you have reached this month's activity goals. You are doing very well. We want you to keep it up."

Videos Screen

The videos screen will contain educational materials designed to increase participants' knowledge and awareness of physical activity in HF. The educational content will be developed based on evidence-based scientific sources. In addition, exercise videos recorded by the expert physiotherapist during the supervised exercise sessions will be uploaded to this section. Participants will be able to access these videos and perform the demonstrated exercises independently at home.

Throughout the intervention period, physical activity and heart rate data obtained from smart wristbands will be monitored through the mobile application. The application will provide visual feedback and support participants in tracking their activity levels, reaching their exercise goals, and integrating physical activity into their daily routines.

Control Group

Participants assigned to the control group will receive standard care and individualized structured verbal education. The education will cover the importance and benefits of physical activity in HF, practical recommendations for daily physical activity, and precautions to be considered before, during, and after exercise.

Unlike the intervention group, participants in the control group will not receive the mobile application or smart wristbands as part of the study intervention. Their follow-up assessments will be conducted through telephone contact.

Outcome Measures

Primary Outcome

The primary outcome of the study is the change in physical activity behavior following the mobile application-supported intervention. Physical activity will be assessed using the SIMPAQ.

The SIMPAQ is a validated and reliable instrument designed to assess physical activity and sedentary behavior over the previous seven days. It consists of five self-reported items addressing time spent in bed, sedentary activities, walking, exercise, and incidental daily activities. Moderate-to-vigorous physical activity duration is calculated by summing the reported walking and exercise durations. The Turkish validity and reliability of the questionnaire have been established.

The SIMPAQ will be administered to participants in both groups during the study follow-up period. Participants in the intervention group will access the questionnaire through the mobile application, whereas participants in the control group will complete it through telephone-guided assessment.

Secondary Outcome

The secondary outcome is health-related quality of life. This outcome will be evaluated using the LVD-36. The LVD-36 is a disease-specific questionnaire developed to assess the effects of left ventricular dysfunction on daily life and well-being in individuals with HF. It consists of 36 items with true/false response options. Scores range from 0 to 100, with higher scores indicating poorer quality of life. The Turkish validity and reliability of the questionnaire have been established.

Data Collection

Data will be collected using three instruments:

Introductory Information Form: This researcher-developed form will collect sociodemographic and clinical information, including age, gender, weight, height, marital status, educational status, employment status, household composition, current medical diagnoses, duration of HF diagnosis, smoking and alcohol use, current medications, and symptoms and complaints before hospital admission. This form will be administered at baseline.

SIMPAQ: This questionnaire will be used to assess participants' physical activity and sedentary behavior.

LVD-36: This questionnaire will be used to assess health-related quality of life.

Statistical Analysis

Study data will be analyzed using SPSS statistical software. Descriptive statistics, including means, standard deviations, frequencies, and percentages, will be used to summarize participants' demographic and clinical characteristics. Baseline characteristics of the intervention and control groups will be compared using appropriate parametric or nonparametric statistical tests, including the independent samples t-test or Mann-Whitney U test, and one-way ANOVA or Kruskal-Wallis test, as appropriate.

Changes in physical activity scores measured using the SIMPAQ will be evaluated through repeated measures analysis of variance, considering group and time effects and their interaction. Health-related quality-of-life scores measured using the LVD-36 will be compared between groups using appropriate statistical methods. The findings will be interpreted in relation to the primary and secondary outcomes of the study.

Study Limitations

This study will be conducted at a single center among patients with HF followed at the cardiology outpatient clinics of İzzet Baysal Education and Research Hospital in Bolu, Türkiye. Therefore, the generalizability of the findings to the broader population of individuals with HF may be limited.