{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T18:07:25Z","timestamp":1790791645846,"version":"4.1.0"},"reference-count":21,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"7","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circ: Cardiovascular Quality and Outcomes"],"published-print":{"date-parts":[[2024,7]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND:<\/jats:title>\n                    <jats:p>Text messages may enhance physical activity levels in patients with cardiovascular disease, including those enrolled in cardiac rehabilitation. However, the independent and long-term effects of text messages remain uncertain.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS:<\/jats:title>\n                    <jats:p>The VALENTINE study (Virtual Application-supported Environment to Increase Exercise) was a micro-randomized trial that delivered text messages through a smartwatch (Apple Watch or Fitbit Versa) to participants initiating cardiac rehabilitation. Participants were randomized 4\u00d7 per day over 6-months to receive no text message or a message encouraging low-level physical activity. Text messages were tailored on contextual factors (eg, weather). Our primary outcome was step count 60 minutes following a text message, and we used a centered and weighted least squares mean method to estimate causal effects. Given potential measurement differences between devices determined a priori, data were assessed separately for Apple Watch and Fitbit Versa users over 3 time periods corresponding to the initiation (0\u201330 days), maintenance (31\u2013120 days), and completion (121\u2013182 days) of cardiac rehabilitation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS:<\/jats:title>\n                    <jats:p>One hundred eight participants were included with 70\u2009552 randomizations over 6 months; mean age was 59.5 (SD, 10.7) years with 36 (32.4%) female and 68 (63.0%) Apple Watch participants. For Apple Watch participants, text messages led to a trend in increased step count by 10% in the 60-minutes following a message during days 1 to 30 (95% CI, \u22121% to +20%), with no effect from days 31 to 120 (+1% [95% CI, \u22124% to +5%]), and a significant 6% increase during days 121 to 182 (95% CI, +0% to +11%). For Fitbit users, text messages significantly increased step count by 17% (95% CI, +7% to +28%) in the 60-minutes following a message in the first 30 days of the study with no effect subsequently.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS:<\/jats:title>\n                    <jats:p>In patients undergoing cardiac rehabilitation, contextually tailored text messages may increase physical activity, but this effect varies over time and by device.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>REGISTRATION:<\/jats:title>\n                    <jats:p>\n                      URL:\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"https:\/\/www.clinicaltrials.gov\">https:\/\/www.clinicaltrials.gov<\/jats:ext-link>\n                      ; Unique identifier: NCT04587882.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1161\/circoutcomes.123.010731","type":"journal-article","created":{"date-parts":[[2024,6,18]],"date-time":"2024-06-18T05:00:55Z","timestamp":1718686855000},"update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":20,"title":["Text Messages to Promote Physical Activity in Patients With Cardiovascular Disease: A Micro-Randomized Trial of a Just-In-Time Adaptive Intervention"],"prefix":"10.1161","volume":"17","clinical-trial-number":[{"clinical-trial-number":"nct04587882","registry":"10.18810\/clinical-trials-gov"}],"author":[{"given":"Jessica R.","family":"Golbus","sequence":"first","affiliation":[{"name":"Division of Cardiovascular Diseases, Department of Internal Medicine (J.R.G., R.S., V.S.E.J., E.L., S. Kohnstamm, B.K.N.), University of Michigan."},{"name":"Michigan Integrated Center for Health Analytics and Medical Prediction (MiCHAMP) (J.R.G., B.K.N.), University of Michigan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1108-1558","authenticated-orcid":true,"given":"Jieru","family":"Shi","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor (J.S., W.D.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kashvi","family":"Gupta","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, University of Missouri Kansas City (K.G.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rachel","family":"Stevens","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Diseases, Department of Internal Medicine (J.R.G., R.S., V.S.E.J., E.L., S. 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Kohnstamm, B.K.N.), University of Michigan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Boyden","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Diseases, Department of Internal Medicine, Spectrum Health, MI (T.B.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0118-4561","authenticated-orcid":true,"given":"Bhramar","family":"Mukherjee","sequence":"additional","affiliation":[{"name":"School of Public Health (B.M., K.R.), University of Michigan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Kohnstamm","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Diseases, Department of Internal Medicine (J.R.G., R.S., V.S.E.J., E.L., S. Kohnstamm, B.K.N.), University of Michigan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-0555-8967","authenticated-orcid":true,"given":"Vlad","family":"Taralunga","sequence":"additional","affiliation":[{"name":"CareEvolution, Ann Arbor, MI (V.T., V.K.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vik","family":"Kheterpal","sequence":"additional","affiliation":[{"name":"CareEvolution, Ann Arbor, MI (V.T., V.K.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6546-0273","authenticated-orcid":true,"given":"Sachin","family":"Kheterpal","sequence":"additional","affiliation":[{"name":"Department of Anesthesiology (S. 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