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Although most of us have gotten the memo that moving more is a good thing, it hasn’t been clear what intensity level is best for shedding weight and improving heart health — and how much is needed to make a measurable difference.
A new analysis published November 10 in the European Heart Journal set out to better understand how different levels of vigorous activity were linked to key factors related to cardiovascular risk, the first-ever study to examine how our movement through a 24-hour day can impact heart health.
“The big takeaway from our research is that while small changes to how you move can have a positive effect on heart health, intensity of movement matters,” said first author Jo Blodgett, PhD, a research fellow in the Institute of Sport, Exercise and Health at University College London in England, in a press release.
Replacing sitting with moderate to vigorous activity (MVPA) that gets your heart rate up and makes you breathe harder, even for just a minute or two, was the most beneficial, says Dr. Blodgett.
These findings — that even small increases in physical activity have health benefits, and that moderate and vigorous activities have the most benefit — make sense and are in line with the latest U.S. Physical Activity guidelines and the scientific statement that went with it, says Michael McConnell, MD, a clinical professor and cardiologist at Stanford Medicine in California, who was not involved in the study.
Per the guidelines, adults need at least 150 to 300 minutes of moderate-intensity aerobic activity, like brisk walking or fast dancing, each week. Adults also need muscle-strengthening activity, like lifting weights or doing push-ups, at least two days each week.
But working up a sweat wasn’t the only activity that reaped health benefits — researchers also found that choosing restful sleep over couch time was associated with shaving off pounds and waistline inches.
Moderate and Vigorous Activity Best, Sitting Is the Worst
Researchers used data from six studies and over 15,000 people from five countries to see how movement across the day (measured by an activity tracker worn on the thigh) was associated with heart health, as measured by body mass index (BMI), waist circumference, cholesterol, triglycerides, and blood sugar levels (HbA1C).
Time spent doing moderate or vigorous activity provided the most benefit to heart health, followed by light activity, standing, and sleeping, compared with the adverse impact of sitting.
Just 5 Minutes of Extra Activity per Day Leads to Improvements
In the second part of the study, researchers created models to estimate the heart-health effects of replacing sitting time with other activities, and found that just five extra minutes of moderate or vigorous activity had a noticeable effect on heart health.
How would that work on a real person? In a 54-year-old woman with an average BMI of 26.5 (calculated by dividing a person's weight in kilograms by their height in meters squared, or kg/m2), a 30-minute change (trading sitting for moderate or vigorous activity) translated into:
- a 2.4 percent decrease in BMI
- a 2.5 centimeters (2.7 percent) decrease in waist circumference
- and a 1.33 mmol/mol (3.6 percent) decrease in blood sugar
Moderate exercise is any activity that raises your heart rate and makes you breathe faster — things like brisk walking, cycling, dancing, or doing lawn work, says Blodgett. “The heart rate zone would be 65 to 75 percent of your maximum heart rate.”
Maximum heart rate is about 220 minus your age, according to the American Health Association (AHA). For a 54-year-old woman, that would be 166, which would make the moderate heart rate zone between 108 and 125 beats per minute.
“Vigorous activities could include playing sports, running, or even short bursts of normal activity like climbing stairs or moving heavy boxes. Most moderate activities can become vigorous activities if you increase your effort so that you are working above 75 percent of your maximum heart rate,” says Blodgett.
Generally, an activity is classed as moderate intensity if you can talk but not sing while doing it, and an activity is generally considered vigorous intensity if you can’t say more than a few words without stopping to breathe, she says.
How Small Changes Lead to Big Benefits
The cardiovascular demands of even small amounts of high intensity activity can lead to improved heart health, explains Blodgett.
Dr. McConnell agrees, saying, “Even small amounts of increased activity are now shown to have health benefits.”
Previously, the guidelines stated an exercise bout had to last at least 10 minutes to be considered toward the weekly goal, he points out. “Based on more research, that requirement was removed, so literally every minute does count,” he says.
That being said, more activity is better, and when possible, higher intensity activity is always best, she says.
“Exercise and activity have many positive effects on the heart. When we exercise regularly, the heart becomes stronger and more efficient. It pumps blood more effectively, which improves blood flow throughout the body. This can lower cholesterol, blood pressure, and resting heart rate,” says Blodgett.
Sleep Trumps Sitting for Health Improvements
Trading 30 minutes of sitting for 30 minutes of sleeping each day lowered overall BMI by nearly .5 kg/m2 and sliced about 2/3 inch (1.75 centimeters) from waist circumference, according to the findings.
The finding that sleep time was better than sedentary time was interesting, but consistent with recommendations, says McConnell.
More Research Is Needed to Confirm That Activity Is Causing the Improvements
These findings are very much in line with the current evidence on movement and heart health, says Melody Ding, PhD, MPH, an associate professor and researcher at the Sydney School of Public Health in Australia, who was not involved in the study.
An study published in October 2022 in the European Heart Journal found that two minute bursts of vigorous activity totaling 15 minutes a week were associated with an 18 percent lower risk of death and a 15 percent lower likelihood of heart disease. More vigorous activity was linked with even better outcomes: Bursts that added up to 53 minutes per week were associated with a 36 percent lower risk of death from any cause.
‘Know Your Numbers’ and Reduce Your Risk for Heart Disease
Factors that put you at risk for heart disease — prediabetes, high cholesterol, and high blood pressure — often have no clear symptoms or warning signs, according to the AHA.
“It is always useful for individuals to better understand their cardiometabolic health by attending routine check-ups with their doctor. Understanding if your BMI, waist circumference, cholesterol, or blood sugar are in a healthy range can help identify if you are at higher risk for cardiovascular disease,” says Blodgett.
“Your doctor can provide guidance on lifestyle changes that can help reduce this risk. Increasing physical activity and reducing time spent sitting is a great place to start,” she says.
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