IMPROVING ADHERENCE TO EXERCISE REGIMENS POST-MI THROUGH A NOVEL TEXT MESSAGE REMINDER SYSTEM

Abstract

Regular and structured exercise after myocardial infarction (MI) has been demonstrated to reduce the risk of recurrent cardiac events by 30-50% but non-adherence to exercise regimens is extremely common. While the causes of inactivity in post-MI patients have yet to be fully described, forgetfulness is believed to be a central contributor. With the proliferation of cell phones, text message reminders may be a cost effective strategy to remind people to exercise. We recruited patients recently discharged after MI who were receiving care at a single cardiac rehabilitation facility. To be included, all individuals had to be within 2 weeks of their MI and be able to read and understand English. Individuals without cell phones and those that unwilling or unable to provide informed consent were excluded. Participants were randomized into usual care or to receive text message reminders four times daily that simply stated "Please remember to exercise 45 minutes today". The co-primary outcomes were the frequency of exercise and the total duration of exercise, assessed through self-reported logs. In additional, physical endurance and aerobic fitness was tested in all participants through exercise treadmill testing at baseline, month 3 and month 12. Fifty patients were randomized. Patients were on average 64 years of age. Intervention and control patients had similar baseline characteristics. In the control group, activity fell over time from an average of 683 minutes of exercise (over an average of 17 days) at month 1 to 416 minutes of exercise (over an average of 11 days) by month 12. By contrast, intervention groups patients exercised 772 minutes (over an average of 18 days in month 1) and 794 minutes of exercise (over 18 days) in month 12 (p<0.0001 for difference between intervention and control at month 12). By month 12, aerobic fitness and cardiac endurance as measured on a cardiac stress test was greater among intervention patients (7.4 METS vs. 6.2 METS, p<0.038). In all sub-groups analyzed, text message reminders significantly improved activity and exercise endurance measures. The frequency of exercise, its duration and objective cardiac endurance and aerobic fitness improved significantly with a simple automated text-message exercise remind system. While the impact of this intervention on health outcomes has not been established, it represents a simple and scalable method for improving adherence to exercise regimens among post-MI patients.