In a recent study published in European Heart Journal, researchers demonstrated the advantages of moderate amounts of vigorous physical activity (VPA) accomplished in brief bouts in reducing the danger of heart diseases and cancers.

Study: Vigorous physical activity, incident heart disease, and cancer: how little is enough? Image Credit: Air Images/Shutterstock

Background

The physical activity guidelines for Americans (second edition) and the 2020 World Health Organization (WHO) guidelines recommend 150 to 300 minutes of moderate-to-vigorous physical activity (MVPA) as a time-efficient substitute for normal exercise or achieving advisable physical activity levels.

Although based on prospective observational evidence, several studies have evidenced the health advantages of VPA. As an illustration, a recent study showed that when VPA contributed 30 to 50% of total MVPA time, it lowered all-cause mortality (ACM) risk by ~10%. Nevertheless, there’s a lack of awareness about how much VPA (VPA volume) is required to enhance health and reduce mortality and disease incidence, especially cardiovascular diseases (CVDs) and cancers. Notably, device-based measurements are perfect for examining the dose response of short and intermittent VPA bursts.

In regards to the study

In the current study, researchers enrolled 502629 participants, within the age group of 40 to 69 years, from the UK Biobank study between 2006 and 2010 to look at the dose-response association of device-measured VPA with mortality and CVD and cancer incidence. They excluded participants with prevalent CVD or cancer or diagnosed with any such event throughout the first 12 months after the landmark.

The team mailed an Axivity AX3 accelerometer to 103,684 participants between 2013 and 2015. They initialized all devices to gather data at 100 hertz (Hz) sampling frequency and a dynamic range between ± 8 g. The team asked all of the participants to wear the AX3 accelerometers on their dominant wrist for twenty-four hours per day for seven days for physical activity assessments. They considered the beginning of the landmark period, denoted by the point of the accelerometry measurements, because the onset of follow-up time.

When the participants returned the devices, the researchers calibrated their data and identified non-wear periods per standard protocol. Only that data was analyzed or considered valid when the participants wore the device for greater than 16 h. Also, each participant needed a minimum of 4 valid monitoring days, with not less than one in all those days being a weekend day, to be included within the study evaluation.

The study’s physical activity scheme used features within the raw acceleration signal to quantify the time spent in several physical activities and their respective intensities in a ten seconds window. The team calculated the VPA volume for every participant by summing the time spent in each activity intensity band across all valid wear days. Notably, 96% of VPA volume occurred in bouts lasting as much as two minutes.

The study outcomes included ACM, CVD mortality, and cancer mortality, plus cancer and CVD incidence by VPA volume groups (no VPA to lower than zero, 10, 30, 60 minutes per week, and ≥60 minutes per week). The team followed up with all of the participants till October 31, 2021, for all final result ascertainments. They used Poisson regression to calculate the dose-response absolute risk between VPA volume and every final result and Cox proportional hazard model to compute hazard ratios (HRs).

Study findings

The authors noted a consistent non-linear inverse correlation between VPA and all-cause and cancer mortality; nevertheless, the correlation between VPA and CVD mortality was a linear dose-response type. Furthermore, there have been comparable results for the optimal and minimal dose-induced incident disease and mortality, with a steep gradient for five-year CVD incidence risk. The present advisable 75 minutes per week of VPA were related to the bottom risk in dose-response curves for all three mortality outcomes.

While ∼quarter-hour per week of VPA lowered all-cause and cancer mortality by 16 to 18%, 20 minutes per week reduced CVD mortality risk by 40%. Nevertheless, ∼53 minutes per week of VPA was related to 36% lower ACM, with modest additional useful associations for more VPA. Individuals with poor fitness or cardiovascular and cancer risk aspects (e.g., obesity) accumulating VPA in brief bouts of as much as two minutes (4 times a day) lowered their mortality risk by 27%.

Intriguingly, potentially useful VPA volume doses identified within the study were consistent across age, sex, and health risk aspects. Thus, clinicians and health practitioners could encourage participation in VPA of any length throughout the day for adults of all ages and ensure their long-term engagement and adherence.

Conclusions

Prior questionnaire-based studies suggested 60 to 70 minutes per week of VPA attenuate mortality risk by 30%. Based on the device-based findings of the present study, a minimum of 20 minutes per week of VPA provided similar levels of lower mortality risk. Despite differences in constructs, the authors noted a ∼3:1 equivalence of VPA time captured by questionnaires and accelerometers.

Previous device-based studies measured physical activity in one-minute intervals (lower resolution). It may need masked short VPA durations and led to an underestimation of VPA volume. The present study used a better physical activity resolution (10 seconds) and located that 92% of VPA durations lasted one minute or less. Overall, the study findings are quite relevant from a clinical perspective because time constraint stays essentially the most commonly cited barrier to regular physical activity across age groups, genders, ethnicities, and health statuses.