Do you work in an office all day and then relax on the couch? Beware, your heart could be in danger. Even if you exercise in your free time. That's according to a large new study that followed tens of thousands of people for 8 years. Researchers found that sedentary prolonged (spending many hours sitting, lying down or reclining, apart from sleeping at night) increases the risk of heart problems and cardiovascular death.
The critical threshold seems to be 10,6 hours a day. Exceeding it increases the probability of heart failure (+45%) and death from cardiovascular causes (+62%). Numbers that make you think. But don't panic: a few simple moves are enough to reduce the risks. Curious to know them? I'll reveal them all to you.
Sedentary lifestyle is bad, even if you train afterwards
The study, published in Journal of the American College of Cardiology (I link it here) adds an important piece to the growing body of evidence about the dangers of a sedentary lifestyle. We already knew that too much sitting was bad for our health. But it was thought that getting enough physical activity could compensate. The latest research challenges even that belief.
The researchers analyzed data from nearly 90.000 participants in the UK Biobank study. To accurately measure their activity levels, they used special wearable devices called accelerometers. They followed them for an average of 8 years, discovering a very close link between a sedentary lifestyle and heart risks.
In particular, spending many hours sitting significantly increased the risk of atrial fibrillation, myocardial infarction, heart failure and cardiovascular death. And beware: these risks remained high even for those who met physical activity guidelines (150 minutes of moderate-intensity exercise per week).
The critical threshold of 10 hours of sedentary lifestyle
On average, participants spent 9,4 hours sitting per day. But a point of no return has emerged: 10,6 hours a day. Those who exceeded this threshold (the most sedentary 25% of the sample) had a 45% higher risk of heart failure and a 62% higher risk of cardiovascular death. Alarming data.
“Our findings support the idea of reducing sedentary time to reduce cardiovascular risk, with 10,6 hours per day appearing to be a key threshold linked to increased heart failure and cardiovascular mortality,” Shaan Khurshid, a cardiologist at Massachusetts General Hospital and co-senior author of the study.
“Too much sitting can damage heart health, even for active people.”
Why is too much sitting so bad?
The exact mechanisms are not yet fully understood. But there are some hypotheses: Sitting for long periods reduces blood flow and negatively impacts insulin sensitivity, for example. Furthermore, the causal link between sitting and health problems is so strong that experts are urging us to find ways to reduce the hours we spend sitting.
“This study adds to the growing evidence of a strong link between sedentary behavior and cardiovascular health,” he commented. Harlan Krumholz, professor at the Yale School of Medicine and editor-in-chief of JACC. “The findings clearly suggest that we need to encourage people to move more to promote better health.”
Strategies to reduce risks
Of course, exercise remains a powerful tool for maintaining heart health. But as Dr. Khurshid noted, current guidelines only cover a small portion of the day. In addition to sitting less, researchers have found that adding light activity can make a big difference.
Simply replacing 30 minutes of sedentary lifestyle with some movement, even light, can significantly reduce the risks. For example:
- 30 minutes of light activity (slow walking, housework) instead of sitting reduced the risk of cardiovascular death by 17%;
- 30 minutes of moderate activity (brisk walking, gardening) instead of a sedentary lifestyle lowered the risk of heart attack by 31%
- Replace half an hour sitting with intense exercise (running, swimming) decreased the risk of heart failure by as much as 36%
Accelerometers, precious allies
These high-tech wristbands that measure movement (but not perfect posture) in multiple directions have proven to be much more reliable than questionnaires. Participants tended to overestimate how much exercise they had done and underestimate sedentary lifestyle. Accelerometers, on the other hand, provide objective, minute-by-minute data.
The widespread adoption of accelerometers opens new doors to truly understand and address public health challenges. In the future, they could be used on larger and more diverse populations, perhaps integrating them with heart rate monitors or posture sensors, for an even more complete view.
Small steps towards a healthier life
In short, the message is clear: Too much sitting is seriously harmful to the heart. The good news is that the risks can be reduced. Here are some simple strategies to cut down on sedentary behavior:
- Take movement breaks during your workday by getting up and walking around every hour;
- Find an “accountability buddy” with whom you can share activity goals and encourage each other;
- Instead of relaxing on the couch, take a walk after dinner;
- When possible, choose the stairs instead of the elevator or escalator;
- Park further away and get off the bus one stop earlier to get a few more steps.
The heart is the engine that runs your body, every little step can strengthen it. Whether it's replacing half an hour of TV with a walk, standing at your desk (without excess) or during phone calls or stretching between activities, these mini-changes can have big benefits for your health.
Science is clear: movement matters, not just in the gym but throughout the day. Let's get up, put a pause on our sedentary lifestyle, and give our hearts a gift!
