This research is being done to learn if a smartphone app with and without a just in time adaptive intervention (JITAI) can help patients with hypertension manage their sodium intake and improve their blood pressure.

The primary and secondary outcomes will be determined in months 1 & 2. Participants will continue for another 4 months and during that time data for exploratory measures will be collected.

During the first 2 months of the study, a micro-randomized trial (MRT) will be performed within the App+JITAI group (N=200). This MRT is designed to learn which push notification messages effectively prompt the user to interact with the appropriate content within the mobile application.

Inclusion Criteria:

1. Diagnosed with essential hypertension (HTN) by a medical provider and are on stable doses of antihypertensive therapy for at least three months prior to enrollment as documented in the electronic health record (EHR) and confirmed by participant self-report.
2. A smartphone with a compatible Apple or Android operating system installed and able to download and use LowSalt4Life app including accepting all permissions and willing to allow the mobile applications to send push notifications
3. A valid email address
4. Fluent in spoken and written English

Exclusion Criteria:

1. Unstable symptoms or markedly elevated blood pressure (BP) at enrollment (defined as systolic BP>180 mmHg, diastolic BP>120 mmHg)
2. Contraindication to a sodium restriction diet
3. An estimated sodium intake less than 1,500mg per day
4. Known secondary causes of HTN (e.g., adrenal insufficiency, pheochromocytoma)
5. Estimated glomerular filtration rate (EGFR) <30 or end-stage renal disease on dialysis
6. Heart failure
7. Inability to use Withings devices (blood pressure cuff and scale) due to equipment limitations or contraindications
8. Currently pregnant or intent to become pregnant during the study period

The aim is to prepare data for deposit into the National Heart, Lung, and Blood Institute (NHLBI) supported Biologic Specimen and Data Repositories Information Coordinating Center (BioLINCC).Unique research data be made available to the scientific community after the conclusion of a study. The de-identified analytic data will be prepared as SAS transport files or ASCII comma-delimited files with accompanying codebooks that describe the data and data structure. The redaction will employ best practices and will be consistent with National Heart, Lung, and Blood Institute data sharing policies.

Unique research data be made available to the scientific community after the conclusion of a study. No later than 3 years after the end of the study or 2 years after the main paper reporting the results of the trial, whichever comes first.

The scientific community will have access to the data deposited into the National Heart, Lung, and Blood Institute (NHLBI) supported Biologic Specimen and Data Repositories Information Coordinating Center (BioLINCC). Researchers at institutions with a Federal Wide Assurance will be able to gain access to repository data by submitting a data access request in accordance with applicable policies.

Participants randomized to the App+JITAI will receive push notifications throughout the study, while those in the App alone group will not. The participants will not be told the group in which they are randomized, but they may know the group because of the number of push notifications.