A recent study led by Dr. Keith Diaz, the Florence Irving Associate Professor of Behavioral Medicine at Columbia University Medical Center, has uncovered compelling evidence that replacing just 30 minutes of sitting with exercise can dramatically lower the risk of a second heart attack. This groundbreaking research indicates that individuals who have previously experienced a cardiac event can greatly benefit from increasing their physical activity levels.
The study, published in the journal Circulation: Cardiovascular Quality and Outcomes, highlights the dangers of prolonged sedentary behavior. An exercise physiologist certified through the American College of Sports Medicine and a volunteer with the American Heart Association’s Physical Activity Science Committee, Dr. Diaz underscores the risks of excessive inactivity. He cautions that sitting for more than 14 hours a day can more than double the risk of having a subsequent cardiac event or being re-hospitalized within a year of the initial event.
In fact, the research shows that substituting 30 minutes of sitting with moderate to vigorous activity can cut the risk of a second heart attack by an impressive 61%. Even swapping out that time for light-intensity physical activity cuts the risk of secondary heart events or death in half. Even more astonishing, choosing sleep over sitting reduces the risk by 14%.
Dr. Diaz emphasizes the significance of reducing sedentary time, stating, “Given all that has been learned from research on the health hazards of sitting, we were concerned that heart attack survivors were unknowingly increasing their risk of having another event.”
He further elaborates, “Our study found that patients who spent more time sitting after a heart event had a higher risk of cardiac events and death within a year, irrespective of exercise levels.”
The study included adults discharged from hospital who wore wrist accelerometers for an average of 30 consecutive days after hospital discharge. This technology made possible accurate measurements of sedentary time compared to active time. These findings add to evidence that achieving physical activity recommendations alone is insufficient. For the rest of the day, though, long stretches of sitting—even for active people—can be harmful.
“That’s why we decided to investigate the link between sedentary behavior and secondary heart attack risk,” Dr. Diaz added. He warns against a prevalent misconception held by patients and physicians alike: “Many people focus solely on meeting exercise recommendations, treating it like a checkbox. ‘I got my 30 minutes in, so I’m good and don’t need to move [for] the rest of the day.’ Movement is the tip of the iceberg. It amounts to just 2% of the day for people that do it.”
According to renowned cardiologist Dr. Christopher J. Berg, the real-world impacts of these findings cannot be overstated. “The risks for heart attack survivors are still substantial,” he commented. The reality is, even for those survivors fortunate enough to undergo the most sophisticated procedures and therapies, they still face high risk. That’s why it’s so urgent to identify alternative strategies to mitigate this risk.
Berg further pointed out that even though the findings of the study are alarming, they were to some degree expected. He stated, “Still, it’s important to be cautious with these results.”
Our study shows how increasing awareness and actively working to lower sedentary behavior can make a big difference in health outcomes. This is particularly the case for survivors of heart attacks. Dr. Diaz concludes with optimism about the accessibility of healthier lifestyles post-cardiac events: “While exercise still provides the best ‘bang for your buck’ in terms of the greatest health benefits, our findings are good news for people who may not have the time, ability or desire to exercise. The journey toward a healthier lifestyle post-heart event is more convenient and achievable than we ever thought possible. It’s not just for gym rats—it’s for everybody!
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