Increase of physical activity over time associated with lower HF risk
Six-Year Changes in Physical Activity and the Risk of Incident Heart Failure: The Atherosclerosis Risk in Communities (ARIC) Study
There are data showing that increases in physical activity (PA) over time are associated with lower risks of coronary heart disease (CHD) and total mortality, and that exercise training programs are beneficial for HF patients, but it is not known whether exercise training has an impact on HF prevention .
In this analysis of the prospective, community-based Atherosclerosis Risk in Communities (ARIC) study , the association between 6-year changes in PA and HF risk was evaluated. Moreover, it was assessed whether the association between PA change and HF risk differs across age, race and gender subgroups.
For this analysis, 11,351 participants without CHD or HF at baseline were included, and their PA was assessed using a modified interviewer-administered Baecke Questionnaire  at 2 visits, which were separated by approximately 6 years. PA was converted into a metabolic equivalent of task (MET) using the Compendium of Physical Activities, and classified into moderate (3-6 METS), and vigorous (>6 METS) exercise. A continuous variable of MET*min/week was generated using duration of PA per week and number of months per year. Based on the current American Heart Association (AHA) recommendations  PA levels were subsequently categorized as:
- Recommended: ≥75 min/week of vigorous intensity or ≥150 min/week of any combination of moderate + vigorous intensity exercise
- Intermediate: 1–74 min/week of vigorous intensity or 1–149 min/week of any combination of moderate plus vigorous intensity exercise
- Poor: 0 min/week of moderate or vigorous exercise
The primary outcome was incident HF defined as the first hospitalization or death related to HF.
- Over a median follow-up time of 19 years there were 1750 HF events, including 1693 hospitalizations and 57 deaths due to HF.
- Using individuals with persistently poor PA as the reference group, individuals with recommended activity levels at both visits had the lowest HF risk (HR: 0.69; 95%CI: 0.60-0.80).
- Individuals who increased their level of PA from poor to recommended also had a significantly lower risk of incident HF (HR: 0.77; 95%CI: 0.63-0.93).
- Each 1-SD increase in PA (SD: 512.5 MET*min/week) was associated with an HR of 0.89 (95%CI: 0.82-0.96) for the risk of incident HF, each 750 MET*min/week increase in PA was associated with an HR of 0.84 (95%CI: 0.75-0.95) for HF, and each 1000 MET*min/week increase in PA was linked to a HR of 0.79 (95%CI: 0.68-0.93).
- A decrease in PA category over time compared to stable high PA was associated with an HR for incident HF of 1.18 (95%CI: 1.02-1.36).
- Those with persistently recommended activity had the lowest HF incidence rate (7.1 events per 1000 person/years), and those with persistently poor activity had the highest HF incidence rate (10.2 events per 1000 person-years).
- Results were similar across age (< or ≥ 65 years), race and gender subgroups, without evidence of statistically significant interactions between PA change and these demographic variables on the incident HF outcome.
In a community-based population without baseline CVD, increasing PA over 6 years was associated with reduced HF risk over the next two decades, while decreasing activity over time was associated with greater HF risk. The lowest HF risk was seen among those with persistently recommended PA, but increasing from poor to recommended activity levels over 6 years was associated with a significantly decreased HF risk. These findings suggest that initiating and augmenting PA in middle age may be helpful for HF prevention.