Changes in Physical Activity and Sedentary Behavior During Cardiac Rehabilitation.

OBJECTIVE: To objectively measure changes in both moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB) during and after standard cardiac rehabilitation (CR).

DESIGN: Prospective cohort study.

SETTING: Outpatient CR center.

PARTICIPANTS: Patients (N=135) with acute coronary syndrome (ACS) who completed CR.

INTERVENTIONS: Multidisciplinary CR according to current guidelines.

MAIN OUTCOME MEASURES: The proportion of time spent in MVPA and SB was objectively measured with an accelerometer. The distribution of time in MVPA and SB was also determined (eg, average length of time periods spent in MVPA and SB). All measurements were obtained before CR, after CR, and at 1-year follow-up.

RESULTS: Patients' time in MVPA during waking hours increased by .65% (≈5min) during CR (P=.002) and remained increased at 1-year follow-up (P=.037). The MVPA distribution did not change. During CR, time spent in SB decreased by 2.49% (≈22min; P<.001), and SB time became more fragmented with more breaks and shorter SB periods (P<.001). These SB improvements were maintained at 1-year follow-up (P<.001).

CONCLUSIONS: Patients with ACS achieved a small improvement in MVPA time during CR, but MVPA distribution remained unchanged. More substantial improvements occurred for SB time and distribution. However, by the end of CR, patients still spent relatively little time in MVPA and a long time in SB, which is known to be detrimental to cardiovascular health. Although CR programs have the potential to improve physical behavior, our findings highlight the need to develop adjusted CR targets that address the amount and distribution of MVPA and SB.