Table 1. Summary of included studies.

Study	Participants	Intervention	Outcome measures	Key findings
Duscha, 2018a [28] RCT, USA	n = 25 (Exp 16, Con 9)	12-weeks	Device-measured (Fitbit): steps.day-1, low PA mins.day-1, low PA mins.week-1, moderate-low PA mins.day-1, moderate-low PA mins.week-1, moderate-high PA mins.day-1, moderate-high PA mins.week-1, moderate PA mins.week-1, total active mins.day-1, total active mins.week-1	Exp = NS ↑ steps.day-1, moderate-high PA mins.day-1 and mins.week-1
		Target behaviour = PA
	Age (yr) = Exp 59 (SD 8.1), Con 66.5 (SD 7.2)
		Exp = Vida Health app and commercial Fitbit app–Fitbit Charge tracking + health coaching
				Con = NS ↓ steps.day-1, low PA mins.day-1 and mins.week-1, total active mins.day-1 and mins.week-1. Significant ↓ moderate-low PA mins.week-1 (117±78 vs 50±53; p<0.05), moderate-high PA mins.week-1 (111±87 vs 65±64; p<0.05).
	F (%) = 24%
	Dx = MI ± revascularization (PCI or CABG), valve repair, heart failure or stable angina	Intensity = Weekly prompts
		Purpose = Sustain PA patterns and monitor daily steps
	Setting = Outpatient phase-II CR	Con = Usual care–no specific lifestyle recommendations from study personnel
				Between group difference in moderate-high PA mins.week-1 (Exp 21±103 vs Con -46±36; p<0.05)
			Follow up = Baseline, 12-weeks
Duscha, 2018b [29] RCT, USA	n = 20 (Exp 10, Con 10)	12-weeks	Device-measured (Fitbit): steps.day-1, low PA mins.day-1, low PA mins.week-1, moderate-low PA mins.day-1, moderate-low PA mins.week-1, moderate-high PA mins.day-1, moderate-high PA mins.week-1, moderate PA mins.week-1, total active mins.day-1, total active mins.week-1	Exp = NS ↑ steps.day-1, moderate-low PA mins.day-1 and mins.week-1, moderate-high PA mins.day-1 and mins.week-1, total active mins.day-1 and mins.week-1
		Target behaviour = PA
	Age (yr) = 69 (SD 8.4)
		Exp = Commercial Fitbit app + Fitbit Charge activity tracker + web-based PAD patient information book
	F (%) = 15.8%
	Dx = PAD with intermittent claudication who were sedentary
				Con = NS ↑ steps.day-1 and NS ↓ in all other PA outcomes.
		Intensity = Phone call if did not meet the prescribed steps for 2 consecutive weeks + weekly email with PAD tip of the week
	Setting = Outpatient cardiology clinic			Between group difference in moderate-high PA mins.day-1 (Exp 10±17 vs Con -2±4; p<0.05) and mins.week-1 (Exp 69±122 vs Con -14±31; p<0.05)
		Purpose = Monitor daily steps
			Baseline, 12-weeks
		Con = Hardcopy of PAD information book and physician guidance–no specific lifestyle recommendations from study personnel
Freene, 2020 [39] Pre-Post, Australia	n = 20	6-weeks	Device-measured (accelerometer–Actigraph ActiSleep): MVPA mins.day-1, LPA mins.day-1, SB mins.day-1, % SB.day-1, duration of SB bounts.day-1(mins), number of SB bouts.day-1, number of SB breaks.day-1, vector magnitude counts.day-1, steps.day-1	Effect size for ↓ in SB mins.day-1 was medium (Cohen d = 0.54) and small for % SB.day-1 (Cohen d = 0.25) at 16 weeks.
	Age (yr) = 54 (SD 13)	Target behaviour = SB
		Exp = Vire app and ToDo-CR behaviour change program + Fitbit Flex + GPS data
	F (%) = 15%
				NS ↓ in duration of SB bounts.day-1(mins), number of SB bouts.day-1, and number of SB breaks.day-1 at 16-weeks.
	Dx = CR participants including stable CHD, CABG, PCI, MI
		Intensity = Automatic messages generated from a bank by the system using machine learning. 14–19 push notifications during the 6-week intervention
				NS ↑ in MVPA mins.day-1, LPA mins.day-1, vector magnitude counts.day-1, and steps.day-1 at 6-weeks and 16-weeks.
	Setting = Outpatient phase-II CR
		Purpose = Self-monitoring activity levels and improve behavioural flexibility to change SB
			Baseline, 6-weeks, 16-weeks
		Con = N/A
Grau-Pellicer, 2020 [26] RCT, Spain	n = 41 (Exp 24, Con 17)	8-weeks	Self-report: community ambulation mins.day-1, sitting time hours.day-1	Exp = ↑ community ambulation mins.day-1 (56.85 ± 52.81; P≤0.05; Cohen’s d = 2.58) and ↓ sitting time hours.day-1 (2.96 ± 2.07; P≤0.05; Cohen’s d = 1.22).
		Target behaviour = PA (community ambulation) + SB
	Age (yr) = Exp 62.96 (SD 11.87), Con 68.53 (SD 11.53)
			Baseline, 3-months
		Exp = Fitlab Training app and Fitlab Test app including GPS and accelerometer monitoring + WhatsApp		Con = NS ↑ community ambulation mins.day-1 and NS ↓ sitting time hours.day-1.
	F (%) = 48.7%
	Dx = Chronic stroke
		Intensity = Unclear
	Setting = Community dwelling	Purpose = Supervise adherence to PA guidelines by monitoring walking distance and speed
		Con = Usual care–conventional 3-month face-to-face rehabilitation program
Johnston, 2016 [24] Multicenter RCT, Sweden	n = 166 (Exp 86, Con 80)	6-months	Self-report (unspecified questionnaire): MPA mins.week-1, number of PA sessions.week-1, % exercise >150 min.week-1	Both groups NS ↑ MPA mins.week-1, number of PA sessions.week-1, % exercise >150 min.week-1
		Target behaviour = Medication adherence + achievement of secondary prevention targets
	Age (yr) = Exp 56.8 (SD 8), Con 58.4 (SD 8.6)
	F (%) = 19%	Exp = SUPPORT app = e-diary for drug adherence + interactive patient support tool for information modules and recording data
	Dx = MI		Baseline, 6-months
	Setting = Traditional secondary prevention care including CR
		Intensity = Every second day during the first 2 weeks, then 3 messages per week
		Purpose = Monitor drug adherence and lifestyle behaviours including exercise, weight management and smoking
		Con = Simplified smartphone drug adherence e-diary = report daily use of tricagrelor (medication) without feedback or education modules. Generic SMS if missed a dose.
Kim, 2016 [47] Sub-study of RCT, USA	n = 95 (Exp 52, Con 43)	6-months	Self-report (Godin Leisure-time Exercise Questionnaire): weekly leisure activity score	Both groups NS ↑ weekly leisure activity score
		Target behaviour = Hypertension control- frequency of the use of alcohol, smoking, and exercise
	Age (yr) = 57.6 (SD 8.6)
	F (%) = 68%
			Baseline, 6-months
	Dx = Hypertension	Exp = HealthyCircles app = Wireless self-monitoring program + disease management + Withings Blood Pressure Monitor
	Setting = Community dwelling accessing health facilities
		Intensity = Encouraged to use 3x per week and take 2 measurements per day. If the participant did not meet the frequency for 2 weeks, a reminder email was sent
		Purpose = Wireless self-monitoring of BP and education
		Con = Usual care–HealthComp disease management program
		Both = HealthComp disease management program with HealthComp relaying medical education
Lunde, 2020 [48] Multicenter RCT, Norway	n = 113 (Exp 57, Con 56)	12-months	Self-report (interview): number of 30min moderate-to-vigorous intensity exercise sessions per week. Baseline, 12-months	Exp = ↑ number of 30min moderate-to-vigorous intensity exercise sessions per week within group change from baseline to 12-moths (1.4±1.5, p<0.001)
		Target behaviour = PA
	Age (yr) = 59 (SD 8.7)
		Exp = Vett app = activity monitoring and feedback + goal setting + communicate with supervisor. Intensity = Motivational feedback 1-3x per week based on individual preference. Purpose = Set goals and reminders related to health behaviours. Con = Usual care–general advice according to a heart-friendly lifestyle and follow-up by their general practitioner
	F (%) = 22.1%
	Dx = Heart disease including 73.4% CAD, 16.8% valve surgery and 9.8% other heart diseases
				Con = ↑ number of 30min moderate-to-vigorous intensity exercise sessions per week within group change from baseline to 12-moths (0.6±1.1, p<0.001)
	Setting = Varying CR programs across inpatient and outpatients
				Between group difference favoured Exp number of 30min moderate-to-vigorous intensity exercise sessions per week (0.9, 95% CI 0.4–1.4; p<0.001).
Lv, 2017 [40] Pre-Post, USA	n = 149	6-months	Self-report (Stanford Exercise Behaviour Scale): mins.week-1 aerobic exercise, mins.week-1 stretching or strengthening	↑ mins.week-1 aerobic exercise (178.6±132.4 vs 206.4±126.2,P = 0.03)
	Age (yr) = 62.2 (SD 9.5)	Target behaviour = PA
				No change mins.week-1 stretching or strengthening (P = 0.91).
	F (%) = 51%	Exp = EMPOWER-H app + Numera app + Web-based dashboard + Nurse Care Manager + wireless BP cuff, pedometer
	Dx = Hypertension
			Baseline, 6-months
	Setting = Ambulatory healthcare system
		Intensity = Instructed to measure and upload BP 2x day for at least 3 days per week and upload daily step count
		Purpose = Support timely patient-provider interaction and personalized feedback for chronic disease management
		Con = N/A
Nabutovsky, 2020 [44] Pre-Post, Israel	n = 22	6-months	Device-measured (smartwatch with matching smartphone Polar application—Polar Inc, M430; Kempele, Finland): steps.day-1, aerobic exercise mins.week-1, frequency of aerobic exercise.week-1, frequency of resistance exercise.week-1, attainment of 150min.week-1 of aerobic exercise. Baseline, 6-months	↓ frequency of aerobic exercise.week-1 (P = 0.03) and ↑ frequency of resistance exercise.week-1 (P = 0.02). NS ↓ steps.day-1 and aerobic exercise mins.week-1. No reported change in attainment of 150min.week-1 of aerobic exercise at follow-up.
	Age (yr) = 52.7 (SD 5.5)	Target behaviour = PA. Exp = Tele-CR with Datos Health app + care-team dashboard + smartwatch with Polar application. Intensity = Tele-health specialist consultation weekly via the messaging system or phone call. Exercise program updated every 5-weeks. Purpose = Remote monitoring, communication and management for secondary prevention. Con = N/A
	F (%) = 22.7%
	Dx = CAD
	Setting = Outpatient cardiac prevention and rehabilitation centre
Paul, 2016 [37] Non-RCT, Scotland	n = 24 (Exp 16, Con 8)	6-weeks	Device-measured (accelerometer–Actigraph ActivPAL): steps.day-1, sedentary time hours.day-1, upright time hours.day-1, walking time hours.day-1	Exp = NS ↑ steps.day-1, upright time hours.day-1, and walking time hours.day-1. NS ↓ sedentary time hours.day-1.
		Target behaviour = PA
	Age (yr) = 56 (SD 10)
		Exp = STARFISH mobile phone app which users’ PA is visualized by fish swimming in a tank in virtual groups of 4
				Con = NS ↓ steps.day-1, walking time hours.day-1 and sedentary time hours.day-1. NS ↑ upright time hours.day-1.
	F (%) = 52%
	Dx = Stroke
			Baseline, 6-weeks
				For group-time interaction, steps.day-1 ↑ by 39.3% (4158 to 5791 steps.day-1) in Exp and ↓ by 20.2% (3694 to 2947 steps.day-1) in Con (P = 0.005; and a large effect, partial η2 = 0.314). Similar group-time interaction occurred for walking time hours.day-1 with ↑ in Exp walking time hours.day-1 by 20mins and ↓ in Con by 14mins (P = 0.002; and a large effect, partial η2 = 0.381).
		Intensity = Weekly increase in step goal
	Setting = Stroke support groups
		Purpose = Behavioural change intervention to encourage the user to become more physically active
		Con = Usual care–no active rehabilitation, only appointments with health care professionals as required
Persell, 2020 [38] RCT, USA	n = 333 (Exp 166, Con 167)	6-months	Self-report (unspecified questionnaire): MVPA mins.week-1. Baseline, 6-months	Exp = NS ↑ MVPA mins.week-1. Con = NS ↑ MVPA mins.week-1. NS between-group differences.
	Age (yr) = 58.9 (SD 12.8)	Target behaviour = Hypertension control–PA, diet, medication adherence, BP measurement, sleep, stress management. Exp = Hypertension Personal Control Program (HPCP) = Artificial Intelligence (AI) technology + HPCP coaching app + blood pressure monitor. Intensity = Prompts daily BP measurement in the first week, then weekly prompts thereafter. Unspecified frequency of reminders for medication, PA, weight and diet. Purpose = Promote home-monitoring of BP and behaviour changes associated with hypertension self-management. Con = Omron app—Blood pressure tracking app + home blood pressure monitor, plus routine care as prescribed by their regular clinicians
	F (%) = 61.3%
	Dx = Uncontrolled hypertension
	Setting = Community dwelling receiving care from outpatient clinics
Requena, 2019 [45] Non-RCT, Spain	n = 159 (Exp 107, Con 52)	3-4-weeks	Self-report (unclear): achieving >30 mins.day-1	No baseline measures completed. Between-group difference at 90 days for achieving >30 mins.day-1 was NS.
	Age (yr) = 58.4 (SD 11.4)
	F (%) = 44%	Target behaviour = PA + medication adherence. Exp = Farmalarm app for secondary prevention of stroke through vascular risk factor control = register obs + GPS + education + communicate with medical staff. Intensity = Medication alarm reminder at each time it is due. Contact with stroke team could be scheduled as requested by the participant. Purpose = Increase stroke awareness by medication alerts, chat communication with medical staff, didactic video files and exercise monitoring. Con = Usual care–stroke unit 90 day follow-up visit
	Dx = Stroke
	Setting = Community dwelling following discharge home
			90 days
Salvi, 2018 [25] Multicenter RCT, Spain, Germany and UK	n = 118 (Exp 55, Con 63)	21-weeks	Self-report (custom questionnaire): MPA mins.week-1	Statistical test not performed due to large drop-outs and poor data collection.
		Target behaviour = PA
	Age (yr) = 58 (SD 10)		Baseline, 6-months
		Exp = HeartCycle GEx system available on smartphone and tablet = Mobile Station + Patient Station + Professional Station
				Exp = ↑ MPA mins.week-1
	F (%) = 11%			Con = ↓ MPA mins.week-1
	Dx = CR graduates with CAD
		Intensity = Automatic feedback generated by the system with on average 163 messages sent to each participant
	Setting = Community dwelling following completion of phase-II CR
		Purpose = Motivate patients to adhere to their rehabilitation program through exercise monitoring, guidance, motivational feedback and educational content
		Con = Usual care–Phase 3 standard rehabilitation according to the national procedures of each of the 3 countries. Also asked to report on daily PA on a paper diary
Sengupta, 2020 [41] Pre-Post, USA	n = 10	12-weeks	Self-report (International Physical Activity Questionnaire-Short Form): days of MPA, MPA mins.day-1, sitting mins.day-1, days walked at least 10mins.day-1. Baseline, 12-weeks	NS ↑ in days of MPA, MPA mins.day-1, sitting mins.day-1, and days walked at least 10mins.day-1
	Age (yr) = 64.4 (SD 6.3)	Target behaviour = PA + diet. Exp = HerBeat app for smartphone and smartwatch = collect data on daily PA, HR, eating episodes, mood + personalised messages within the app. Intensity = Weekly encouragement to engage with the app. Purpose = To help women with behavioural self-management through goal-setting, tracking progress and educational videos. Con = N/A
	F (%) = 100%
	Dx = ACS or coronary revascularization in the last 10 years
	Setting = Outpatient cardiology clinic
Song, 2020 [49] RCT, China	n = 106 (Exp 53, Con 53)	6-months	Self-report (unclear): exercise habits according to meeting the American College of Sports Medicine 10th edition of exercise testing and prescription	Exp = ↑ proportion with exercise habits
		Target behaviour = PA		Con = ↑ proportion with exercise habits
	Age (yr) = Exp 54.17 (SD 8.76), Con 54.83 (SD 9.13)
				Between-group difference in exercise habit favouring Exp (93.8% vs 77.1%; P = 0.02).
		Exp = Telemonitoring software called MEMRS-CRS and WeChat app = HR monitoring (with belt) during exercise + personalised feedback. Intensity = Weekly feedback. Purpose = Provide remote CR through telemonitoring including exercise (following FITT principle) and vital signs. Con = Usual care–routine discharge education and outpatient follow-up with advice to exercise regularly. Both = Routine discharge education and outpatient follow-up which included advice to exercise regularly
	F (%) = 13.5%
	Dx = Stable CHD		Baseline, 6-months
	Setting = Community dwelling
Weerahandi, 2020 [46] Pre-Post, USA	n = 17	120-days	Device-measured (wireless pedometer): steps.day-1	NS ↑ steps.day-1
	Age (yr) = 59 (SD 6)	Target behaviour = Hypertension control–PA, diet, weight, BP measurement. Exp = DASH Mobile app + track diet, blood pressure, weight, PA + human coach and coach-facing web-based portal. Intensity = Coach interaction once per week via instant message, SMS or email. Purpose = Track diet, BP, weight, daily PA and coaching for improved hypertension management. Con = N/A
	F (%) = 60%
	Dx = Hypertension
			Baseline (days 1–7), follow-up (days 46–120)
	Setting = Community dwelling
Werhahn, 2019 [42] Pre-Post, Germany	n = 10	2-months	Device-measured (smartphone—iPhone 6SE, Apple Inc., Cupertino, CA, USA, iOS Versions 10.2.1–11.2.1 + smartwatch—Apple Watch 1st Gen., Apple Inc., watchOS Versions 3.1.1–4.2.2): steps.day-1	↑ steps.day-1 (3612 ± 3311 to 7069 ± 5006; p<0.0001)
	Age (yr) = 46.3 (SD 7.8)	Target behaviour = PA
	F (%) = 40%	Exp = Cardio patient monitoring platform (CPMP) for smartphone and Apple smartwatch + Physician’s tablet. Intensity = Optional reminders for medication. Encouraged daily input of vital signs and activity monitoring. Purpose = Remote monitoring through collecting HF symptoms, medication adherence, PA data and vital signs. Con = N/A
	Dx = Newly diagnosed HF with reduced ejection fraction
	Setting = Community following discharge from hospital
			Baseline, 1-month, 2-months
Widmer, 2015 [27] Non-RCT, USA	n = 44 (Exp 25, Con 19)	3-months	Self-report (Health behaviour questionnaire): exercise mins.week-1	Exp = ↑ exercise mins.week-1 (148.1±78.5, p<0.0001)
	Age (yr) = Exp 60.2 (SD 12.1), Con 70.4 (SD 9.9)	Target behaviour = CVD risk factors–PA, weight, BP measurement, diet, laboratory values. Exp = Personal Health Assistant = integrated and personalised interface that tracks, logs, educates and forms actionable tasks. Intensity = Daily reminders for height, weight, BP, lab values, PA and diet. Occasional email reminders if the participant had not logged in recently. Purpose = Tracks, logs, educates and forms actionable tasks for the user to improve health. Con = Usual care–Mayo Clinic phase II CR program for 36 sessions. Both = Standard Mayo Clinic CR program for 36 sessions (approximately 3 months)
	F (%) = 18.2%
	Dx = PCI for ACS			Con = ↑ exercise mins.week-1 (117.3±61.6, p<0.0001)
	Setting = Outpatient phase-II Mayo Clinic CR
			Baseline, 3-months
				NS between-group difference
Widmer, 2017 [20] RCT, USA	n = 71 (Exp 37, Con 34)	3-months	Self-report (unspecified questionnaire): exercise mins.week-1	Exp = NS ↑ exercise mins.week-1
	Age (yr) = Exp 62.5 (SD 10.7), Con 63.6 (SD 10.9)	Target behaviour = PA + diet		Con = NS ↑ exercise mins.week-1
		Exp = Personal Health Assistant (digital health intervention) and web-based application = patients to report dietary and exercise habits throughout CR + educational information. Intensity = Asked participants to log in 3–4 times weekly. Purpose = Tracks, logs, educates and forms actionable tasks for the user to improve health. Con = Usual care–Mayo Clinic phase II CR program for 36 sessions. Both = Standard Mayo Clinic CR program for 36 sessions (approximately 3 months)
	F (%) = 18.3%
	Dx = PCI for ACS		Baseline, 3-months	NS between-group difference—however the intervention group increased by more (179 vs 139mins)
	Setting = Outpatient phase-II Mayo Clinic CR

Note abbreviations: ACS, Acute coronary syndrome; App, Application; CR, Cardiac rehabilitation; CVD, Cardiovascular disease; Con, Control group; CABG, Coronary artery bypass graft surgery; CAD, Coronary artery disease; CHD, Coronary heart disease; Dx, Diagnosis; Exp, Experimental group; F, Female; HF, Heart failure; LPA, Light-intensity physical activity; MPA, Moderate-intensity physical activity; MVPA, Moderate-to-vigorous intensity physical activity; MI, Myocardial infarction; NS, Non-significant; PCI, Percutaneous coronary intervention; PAD, Peripheral artery disease; PA, Physical activity; RCT, Randomised control trial; SB, Sedentary behaviour; SD, Standard deviation.