What’s really scary is that the “sitting disease” can worsen heart function even in people who meet the recommended levels for exercise.
Heart failure is when the heart does not pump efficiently.
This can take the form of pumping too weakly, and/or, not enough blood fills the heart before each beat, and thus, inadequate amounts of blood get pumped.
In its advanced stage, the patient may need supplemental oxygen 24/7.
A study published in JACC and presented at the American Heart Association’s Scientific Sessions 2024 shows that spending more than 10.5 hours a day sitting, reclining or lying down [other than normal sleeping] may significantly increase the risk of heart failure and cardiovascular death.
This effect holds true even for individuals who meet the recommended levels of physical activity.
The study, led by Dr. Shaan Khurshid from Massachusetts General Hospital, tracked data from more than 89,000 participants in the UK Biobank over an average follow-up of eight years.
These participants, who were on average 62 years old, wore accelerometers that measured their physical activity and sedentary behavior.
The results show that while physical activity is essential for cardiovascular health, sedentary time is an equally important factor.
Over the course of the study, 3,638 participants developed atrial fibrillation (AF), 1,854 developed heart failure (HF), 1,610 had a heart attack and 846 died from cardiovascular causes.
Sedentary Time = Disease Time
The researchers found that sedentary time had different effects depending on the outcome.
For AF and heart attack, the risk increased steadily as sedentary time went up.
However, for chronic heart failure and cardiovascular mortality, the risk only rose significantly after participants spent more than 10.6 hours per day being sedentary or sitting.
This finding suggests a critical threshold at which the sitting disease sharply worsens cardiovascular health.
Interestingly, the study also showed that regular exercise (at least 150 minutes per week of moderate-to-vigorous physical activity, as recommended by current guidelines) could reduce (not eliminate) the negative effects of sedentary behavior on risks for AF and heart attack.
But even those who exercised regularly were still at higher risk for heart failure and cardiovascular mortality if they spent more than 10.6 hours a day in a sedentary state (sitting, reclining or napping).
The paper urges people to reduce sitting/reclining/napping to fewer than 10.6 hours a day.
This includes for people who already exercise at least 150 minutes a week.
“Too much sitting or lying down can be harmful for heart health, even for those who are active,” says Dr. Khurshid in the paper.
In an editorial accompanying the study, Dr. Charles Eaton of Brown University notes that wearable accelerometers provide more accurate data on physical activity than self-reported activity levels.
He points out that people often overestimate how much they exercise and underestimate how much time they spend in a chair or their favorite recliner.
Dr. Eaton says that replacing even only 30 minutes of sedentary time with exercise or physical activity could make a difference by lowering cardiovascular disease risk.
For example, instead of your daily 30 minute nap, take a brisk walk around the neighborhood.
There’s no such thing as a “power nap,” but there IS a such thing as a power walk; a brisk walk will recharge you from inside out.
Even light activity, such as a medium pace walk or simple yoga poses, could make a difference, reducing heart failure risk by 6% and cardiovascular mortality by 9%.
To put it bluntly, people need to get off their can more often.
Limitations of the Study
While the study adds to growing evidence linking sedentary behavior to poor cardiovascular outcomes, there are some limitations.
For example, the researchers were unable to determine the exact reasons or locations where people were sitting or lying down for extended periods.
This could be important because sitting at a desk at work for long hours may affect cardiovascular risk differently than sitting at home.
Also, accelerometers worn on the wrist might misclassify standing time as sedentary time, which could impact the results.
Nevertheless, it’s important not to be too nitpicky about various components of the study.
The bottom line is that spending too much time seated during computer work, videogames or TV, or reclined or lying down for napping, is just plain bad for the heart.
How to Sit Less
Start by setting a timer to remind yourself to stand up every 30 minutes.
When working at your desk, try using a standing desk or an adjustable workstation.
If that’s not an option, consider sitting on a stability ball or using a high stool to engage your muscles while working.
Take short walking breaks — whether it’s a lap around the house or a stroll outside for fresh air.
Consider phone calls or meetings as opportunities to stand or walk, too.
If you commute, try parking further away from your destination or using stairs instead of the elevator.
Simple activities like stretching or doing light household chores like tending to the plants also break up long periods of stillness.
