Whether Once a Day or Once a Week, Any Exercise Still Counts Against CVD

As long as people got their weekly recommended moderate to vigorous physical activity (MVPA), it didn't matter if they did it on a "weekend warrior" schedule or more regularly throughout the week, a study found.

Device-measured physical activity data from the U.K. Biobank cohort showed that among those who reached 150 minutes of exercise a week, both activity patterns were associated with similarly lower risks of incident heart disease compared with inactivity:

• Atrial fibrillation: HR 0.78 for weekend warriors (95% CI 0.74-0.83) and HR 0.81 for active regular (95% CI 0.74-0.88)
• Myocardial infarction: HR 0.73 for weekend warriors (95% CI 0.67-0.80) and HR 0.65 for active regular (95% CI 0.57-0.74)
• Heart failure: HR 0.62 for weekend warriors (95% CI 0.56-0.68) and HR 0.64 for active regular (95% CI 0.56-0.73)
• Stroke: HR 0.79 for weekend warriors (95% CI 0.71-0.88) and HR 0.83 for active regular (95% CI 0.72-0.97)

Clinical outcomes were ascertained over a median 6.3 years of follow-up. Findings were largely similar when raising the bar of exercise to 230 minutes of MVPA per week; only the stroke benefit fell out of significance for people at that level of exercise in either pattern, reported Patrick Ellinor, MD, PhD, of Massachusetts General Hospital of Boston and the Broad Institute of MIT in Cambridge, Massachusetts, and colleagues.

"These observations thereby extend prior work reporting improved cardiovascular outcomes with increasing moderate and vigorous activity, as well as reports suggesting that concentrated physical activity is associated with similar reductions in mortality to more regular activity. Specifically, these findings suggest that engagement in physical activity, regardless of pattern, may optimize risk across a broad spectrum of cardiovascular diseases," they wrote in JAMA.

They noted that there was no excess risk of musculoskeletal injury observed with weekend warrior activity.

"These results highlight the flexibility with which physical activity can be accumulated to achieve health benefits, which should further enhance opportunities for engagement for large segments of the population," commented Peter Katzmarzyk, PhD, of Pennington Biomedical Research Center in Baton Rouge, and John Jakicic, PhD, of the University of Kansas Medical Center in Kansas City.

Department of Health and Human Services guidelines recommend 150-300 minutes of moderate exercise or 75-150 minutes of vigorous exercise each week, along with muscle and strength training twice per week to achieve the most health benefits for adults.

In an accompanying editorial, however, Katzmarzyk and Jakicic went as far as to say "there is no threshold that must be exceeded before benefits begin to occur, and for individuals below the target range, substantial reductions in risk can occur with small increases in physical activity."

"There are clearly benefits to achieving more than 150 minutes of moderate-intensity physical activity per week, but the public health message should also clearly convey that every minute counts, especially among the three-quarters of U.S. adults who do not achieve that goal," they asserted.

Ellinor's group performed an analysis of the subset of U.K. Biobank participants who provided a full week of wrist-based accelerometry data. These were nearly 90,000 individuals averaging age 62, with 56% being women.

With a threshold of 150 minutes of MVPA per week, 42.2% could be considered active weekend warriors (over half of weekly MVPA achieved in 1-2 days), 24.0% active regular exercisers (weekly MVPA more spread out), and 33.7% inactive (fewer than 150 minutes of MVPA weekly).

Yet their reliance on a single weeklong observation window does not capture longitudinal changes in exercise habits, Ellinor and colleagues acknowledged. They added that the study may have limited generalizability due to a predominantly white cohort from a single country.

"Future prospective studies are warranted to assess whether interventions to increase physical activity, even when concentrated within a day or 2 each week, improve cardiovascular outcomes," they said.

For now, Katzmarzyk and Jakicic urged clinicians to familiarize themselves with the physical activity guidelines and prescribe individualized, achievable exercise goals for their patients.

"This allows the prescription to be initiated at lower levels of physical activity and to progress as appropriate based on individual need and ability. Moreover, given that time is often cited as a barrier to physical activity, clinicians can use this information to encourage engagement in physical activity, even at a low level, to enhance the health of their patients," the duo suggested.

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