How much physical activity is needed for heart health?

People can participate in structured exercise such as going to the gym, taking certain classes, or taking time out of their day to cycle, run, or walk. However, finding longer chunks of time to exercise can often be a challenge.

Researchers of the present study wanted to understand how shorter bursts of activity may contribute to cardiovascular health.

The study was a prospective cohort study, and researchers used data from the UK Biobank. The researchers included over 25,000 participants in their analysis. They excluded participants who reported physical activity during leisure time and those who could not walk.

Researchers looked at data on the intervals of moderate-to-vigorous intermittent lifestyle physical activity that participants engaged in, including how many and how long these bursts of activity lasted. Participants wore Axivity AX3 accelerometers for seven days for data collection.

The study accounted for several covariates, including sex, education level, alcohol intake, and intake of fruits and vegetables. The average follow-up duration was 7.9 years. During this time, a total of 824 major adverse cardiovascular events and 1,111 deaths occurred.

In their analysis, researchers found that bouts of physical activity greater than 1 minute were associated with a decreased mortality risk and the risk for major adverse cardiovascular events.

Study author Matthew Ahmadi, a postdoctoral research fellow with Sydney School of Health Sciences, highlighted some key findings of the research to Medical News Today:

“The major findings of the study was using wrist-worn wearables, similar to conventional smartwatches, we found that doing daily activities (such as gardening, household tasks, or walking to the store) with extra effort in brief bursts with a little bit of pace and effort lasting at least 1-5 minutes at a time has health enhancing benefits and can lower the risk of heart attack and stroke by 29-44%.”

Researchers found that even activity bursts for less than one minute were associated with a lower risk for major adverse cardiovascular events, but only when an average of 15% or more of the activity was vigorous.

Regardless, the study indicates that opportunities for reaping the benefits of physical activity abound, even for people who have difficulty exercising during their leisure hours.

Non-study author Dr. Cheng-Han Chen, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, commented to MNT:

“This study is the first to show that even brief periods of physical activity (as low as a few minutes) throughout the day may reduce someone’s risk of death or cardiac event. These findings are promising to public health, as it might be easier for people to incorporate shorter periods of physical activity as a daily habit than a longer structured exercise routine. We can use this information to further promote physical activity especially in patients who are not able to exercise.”

This research does have certain limitations. First, the data is from the UK Biobank, which may not be generalizable to other populations.

Second, researchers only tracked activity levels for one week, indicating that future studies could look at more extended data collection periods.

Researchers cannot completely rule out the possibility of reverse causality and confounding. It is also possible that moderate-to-vigorous intermittent lifestyle physical activity was misclassified, and there is a particular risk for underestimation for heavy lifting of external loads.

There was also an average of a 5.5-year lag between when the data on covariates was collected and when the physical activity measurement with accelerometry occurred. This could have impacted results, such as how medication use changed in this timeframe.

Ahmadi noted the following areas for continuing research:

“Future studies are needed to determine the exact mechanistic pathways from everyday activities done in short bursts that are leading to improved cardiovascular health. Some of the cardioprotective adaptations that occur could be through improved blood pressure, blood sugar control, cardiac output, and reducing our body’s oxidative stress. If the pathways are similar to what we see from exercise-based activities, this may have implications for future prevention and treatment strategies and provide more options and opportunities for people to improve their overall health.”

Overall, the evidence points to the benefits of even short periods of physical activity.

It implies that simple everyday physical activities can provide health benefits. As noted by this study, a few examples could include the following:

• brisk walking
• walking up stairs
• engaging in energetic play with children

Dr. Chen noted the following:

“There are many ways to incorporate even brief physical activity into someone’s lifestyle. They include: taking breaks throughout the day to take a short 5-minute walk (either around the house or around the office), taking the stairs instead of the elevator, parking farther from the store and walking, and walking more briskly when shopping, One can also incorporate physical activity even while doing other things, such as using light weights while watching T.V., or dancing to music.”

Non-study authorDr. Alexandra Lajoie, a noninvasive cardiologist at Providence Saint John’s Health Center in Santa Monica, CA, further added:

“I often tell my patients that if they do not have time for a dedicated exercise regimen, that they should try to fit in any activity that they can find time for including taking the stairs instead of an elevator, parking in farther spots, or doing exercises in place even if they only have a few minutes free during the day.”