Lack of time is often cited as a barrier to undertaking physical activity, so can squeezing exercise into just one to two days a week still provide comparable cardiovascular benefits to a more evenly distributed pattern? Rod Tucker looks at the evidence, in our Review series

There is little doubt that being physically active is associated with health benefits, and current guidance on levels of physical activity for adults is broadly similar across most major countries in the world. The general recommendation is to undertake either at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity, plus two days a week of strengthening activities to work all of the main muscle groups. It is advocated that exercise is spread evenly over four to five days a week or every day.

What evidence is there for this amount of exercise? The health benefits of achieving these exercise goals were assessed in a 2020 study, where researchers looked at the association between attainment of the recommended amount of physical activity and all-cause and cause specific mortality. Their analysis included 479,856 adults and who were followed for a median of 8.75 years. The findings were very clear. Undertaking the recommended amounts of physical activity reduced the risk of all-cause mortality by 40%. However, these benefits also extended to the risk of cardiovascular disease (50% lower) and for cancer (40% lower).

While the health benefits of exercise are clear, many people fail to attain the required amounts of physical activity in their weekly routine. Surveys consistently identify problems in finding sufficient time to exercise as a major barrier, independent of age and gender. Health professionals themselves, don't always practice what they preach - research shows that time constraints are a perceived barrier to exercise among doctors and nurses, but high levels of burn-out and stress are also important barriers. An additional constraint for healthcare professionals is that many work shift patterns, so spreading exercise evenly across the week can be almost impossible.

Active just at the weekend?

Could the same health benefits accrue if physical activity is compressed into just one to two days in a week? There is already some evidence that the so-called 'weekend warriors', i.e., those who restrict physical activity to just one or two sessions per week, have a similar level of all-cause mortality compared to those who spread their physical activity over several days. In fact, a recent meta-analysis of four studies with 426,428 participants, found that the risk of both cardiovascular disease mortality and all-cause mortality in those compressing their activity into two days was 27% and 17% lower respectively, when compared to those who were inactive. A limitation of the included studies was that levels of physical activity were self-reported and are therefore prone to bias.

Accelerometer-derived study

In trying to overcome the inherent bias due to self-reporting, another recent study examined the value of accelerometer device derived data. Researchers set out to examine an association between a ‘weekend warrior’ pattern of moderate to vigorous physical activity (MVPA), achieved over just one to two days, compared to the activity being spread more evenly, with the risk of incident cardiovascular events.

In the study, the team retrospectively analysed a UK Biobank cohort who provided a full week's worth of wrist-based accelerometer physical activity data. Individuals were classified into three groups: ‘active weekend warriors’, in which more than half of their total MVPA was undertaken over one to two days; ‘regularly active’, where exercising was spread throughout the week and finally an ‘inactive’ group, who undertook less than 150 minutes of MVPA per week.

The researchers analysed the associations between the different activity patterns and cardiovascular outcomes such as atrial fibrillation, myocardial infarction, heart failure and stroke. The findings were then adjusted for several potential covariates including, age, sex, ethnicity, alcohol use, levels of smoking and the quality of individual’s diet.

Outcomes for the weekend warriors

Data for 89,573 individuals, with a mean of 62 years (56% female), were included in the analysis and followed for a median of 6.3 years. When stratified at the threshold of 150 minutes or more of MVPA per week, nearly half of the entire cohort (42.2%) were classed as weekend warriors.

Compared to those who were inactive, the weekend exercisers (achieving more than half of their 150 minutes of exercise in just one to two days) had a 22% lower risk of developing atrial fibrillation and a 27% lower risk of a myocardial infarction. Similar findings for heart failure and stroke were seen for the weekend warriors and active group participants.

The key message from the accelerometer-derived study was that engagement in physical activity, regardless of the pattern, is able to reduce the risk of a broad range of adverse cardiovascular outcomes.

In conclusion, when discussing exercise as a part of health promotion with patients, pharmacists can reassure those who feel they have insufficient time that compressing this into a weekend or one to two consecutive days still achieves comparable health benefits.