Exercise and HF Prevention: Is More Better?

Source: Exercise and HF Prevention: Is More Better? | Medpage Today

Physical activity levels at two to four times the federally recommended minimum may reduce the risk of heart failure by 20% and 35% respectively, a meta-analysis of 12 large cohort studies has revealed.

The review also showed that there is a linear, dose-dependent, inverse association between physical activity and heart failure risk that was consistent across age, sex, and geographical region, according to Ambarish Pandey, MD, of the University of Texas Southwestern Medical Center in Dallas, and colleagues.

Current U.S. guidelines, which recommend at least 150 minutes of moderate intensity physical activity a week (500 MET-min/week), were associated with a modest reduction in heart failure risk, Pandey and colleagues noted online in Circulation.

“Physical activity doses in excess of the guideline recommended minimum levels may be required to provide more robust reductions in heart failure risk,” Pandey said in an interview. “Future randomized control trials are needed to compare different doses of physical activity/exercise training interventions to determine the optimum dose of physical activity required for heart failure prevention,” he told MedPage Today.

Heart failure affects more than 5.1 million adults in U.S., and results in healthcare costs of more than $30 billion per year, noted the investigators. What’s more, the prevalence of heart failure is expected to increase by 25% from 2010 to 2030.

“Novel preventive approaches focused on modifying risk factors for heart failure are urgently needed to combat this growing epidemic,” said Pandey and colleagues in their report.

Although previous observational cohort studies have reported an inverse association between physical activity and heart failure risk, this is the largest and most comprehensive assessment in the general population of the dose-response relationship between physical activity and heart failure risk reported to date, said the investigators.

“Previous studies have used dose response meta-analysis of epidemiological studies to better understand the quantitative association between lifestyle risk factors such as coffee intake, dietary patterns and cardiovascular outcomes,” they said. “We have used a similar approach.”

They also pointed out that the observed dose response relationship between physical activity and heart failure risk in the current study was significantly different from that seen between physical activity and coronary heart disease (CHD) risk in a previous study by Sattelmair and colleagues.

While the earlier study reported an inverse dose-response relationships between physical activity and CHD risk, it also showed a 15% reduction in CHD risk with physical activity levels that followed recommended minimum of 500 MET-min/week or even 250 MET-min/week.

Further, Sattelmair and colleagues observed a plateau in the risk reduction for coronary artery disease (CAD) at doses higher than 1,000 MET-min/week, whereas the current study found a 35% risk reduction for heart failure at high physical activity levels as high as 2,000 MET-min/week.

“These findings suggest that while current guideline recommended minimum levels of physical activity might be sufficient to mitigate CHD risk, considerably higher levels of physical activity may be required to achieve reductions in risk for incident heart disease,” said Pandey and colleagues. They added that there might be differences in the mechanisms by which physical activity modifies risk of heart failure versus CHD.

The 12 cohort studies in the meta-analysis included 370,460 participants (53.5% women) and 20,203 heart failure events over a median follow-up of 13 years (Jan. 1, 1995, through Sept. 24, 2014). Participants were older than 18 and categorical dose-response relationships between physical activity and heart failure risk were assessed using random effects models.

Generalized least squares regression models were used to assess the quantitative relationship between physical activity (MET-min/week) and heart failure risk across studies reporting quantitative physical activity estimates.

The review showed that the highest levels of physical activity were associated with significantly reduced risk of heart failure (pooled hazard ratio 0.70, 95% CI 0.67-0.73).

Compared with participants reporting no leisure time physical activity, those who engaged in guideline recommended minimum levels of physical activity (500 MET-min/week, 2008 U.S. Federal Guidelines) had modest reductions in heart failure risk [relative risk 0.90, 95% CI 0.87-0.92).

In contrast, a substantial risk reduction was observed among individuals who engaged in physical activity at twice (HR 0.81 for for 1,000 MET-min/week, 95% CI 0.77-0.86) and four times [HR 0.65 for 2,000 MET-min/week, 95% CI 0.58-0.73) the minimum guideline recommended levels.

Findings from this study might have significant public health implications and could help guide physicians and health policy-makers when recommending physical activity for optimal heart failure risk reduction, said the investigators.

In the meantime, clinicians should encourage sedentary patients to increase their physical activity levels, said Pandey. “The benefits of higher levels of physical activity levels should be emphasized and patients should be encouraged to be as active as can be tolerated based on their clinical condition,” he told MedPage Today.


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