A sedentary lifestyle: a hidden risk with serious effects on heart health
6 minutes read
People who spend more than 10 hours a day being sedentary are at greater risk of heart conditions such as atrial fibrillation, heart failure, myocardial infarction and CV death.
In the modern era, where technology, working patterns, new entertainment habits and comfort have led us to spend long hours sitting, whether at the office, in the car or at home, a sedentary lifestyle has become a silent enemy with serious effects on our health.
But what is a sedentary lifestyle and what are its consequences? It is a way of life characterised by a lack of regular physical activity and a predominance of activities that involve sitting or lying down for long periods. Moving less than the body needs may seem harmless, but its long-term consequences are alarming. Beyond putting on a few extra pounds, a sedentary lifestyle raises the risk of cardiovascular disease, diabetes and muscle disorders, and even affects our mental health.
Although the World Health Organization (WHO) recommends at least 150 minutes of moderate to vigorous exercise a week to reduce the risk of cardiovascular disease, the guidelines do not clearly specify how inactivity directly affects heart health.
A new Mass General Brigham study indicates that more than 10.6 hours of sedentary time a day increases the risk of atrial fibrillation (AF), myocardial infarction, heart failure and cardiovascular death. The study, published in the Journal of the American College of Cardiology, found that this is the case even for people who also do the recommended amount of exercise each week.
“Many people spend several hours a day being sedentary. We wanted to understand whether exercise can cancel out the effects of this behaviour,” says Shaan Khurshid, MD, MPH, a Mass General Brigham cardiac electrophysiologist who sees patients at Massachusetts General Hospital. “Overall, our findings indicate that avoiding excessive sedentary behaviour is important for cardiovascular benefit, whether or not you are physically active.”
How much time do people spend being sedentary on average?
In the Dominican Republic, cardiovascular disease is the leading cause of death. According to the WHO, more than 35% of deaths in the country are attributable to cardiovascular disease. According to the Dominican Ministry of Public Health, 70% of the adult population does not exercise regularly, which puts the population at high risk of heart disease.
Dr. Khurshid recently completed a study of almost 90,000 people who wore activity trackers on their wrists for a week. The researchers collected data on the time and intensity of exercise, as well as on sedentary time. Sedentary time was defined as all the waking time a person spends sitting, reclining or lying down, involving low energy expenditure. Sleeping and standing were not counted as sedentary time.
Average sedentary time was 9.4 hours a day. The researchers divided participants into 4 equal groups:
- The most sedentary group averaged more than 10.6 hours of sedentary time a day.
- The next group ranged from 9.5 to 10.6 hours a day.
- Another group ranged from 8.2 to 9.4 hours a day.
- The group with the least sedentary time averaged less than 8.2 hours a day.
“A total of 10.6 hours sounds like a lot. But if you think of someone who has an office job and then watches some TV in the evening, it actually adds up very quickly,” says Dr. Khurshid. “In the United States the average is estimated at 9.5 hours a day. So 10.6 is higher than average, but it represents the behaviour of a lot of people.”
In the Dominican Republic, more than half of the adult population leads a sedentary lifestyle, according to the 2020 National Health Survey. This trend is alarming given the direct link between physical inactivity and cardiovascular disease.
The effects of a sedentary lifestyle on cardiovascular health
The study then assessed how many people developed four specific cardiovascular conditions over the following 8 years. It found that people in the highest category of sedentary behaviour (more than 10.6 hours) were at greater risk of four significant heart conditions:
- Atrial fibrillation (AF): one of the most common types of irregular heartbeat, or arrhythmia. It can lead to blood clots, stroke, heart failure and other complications.
- Heart failure: in heart failure, the heart does not work as well as it should. This condition can prevent the rest of the body from getting the oxygen it needs.
- Myocardial infarction (heart attack): this medical emergency occurs when blood flow to the heart is blocked, preventing the heart from getting enough oxygen.
- CV death: the study also looked at how many people died from heart-related causes.
The results were especially striking for heart failure and cardiovascular (CV) death. The most sedentary people had a 40% and 60% higher risk, respectively. In addition, the more days a week a person exceeded that 10.6-hour mark, the greater their risk of all four CV conditions.
“Being active is helpful, but it does not completely overcome the risks associated with excessive sedentary time. So, even if you are physically active, it is still important to reduce sedentary behaviour,” notes the Mass General Brigham specialist.
Too much sitting affects heart health, even if you meet exercise recommendations
Interestingly, a lot of sedentary time increased the risk of heart-related problems even in people who did the recommended amount of weekly exercise.
“We looked at people in the high sedentary behaviour category and analysed what would happen to their risk if they swapped sedentary behaviour for any other activity. Even if they only swapped it for light activity. Anything less sedentary: walking, standing, basically doing anything,” says Dr. Khurshid. “We saw a lower risk of heart failure and cardiovascular death. So, if you can build something like that into your day, our study suggests it will help with your risk.”
Dr. Khurshid hopes these findings will motivate people to make small changes and adopt healthy behaviours in whatever way suits them best. He recently completed a study, published in Circulation, showing that “weekend warriors” have a substantially lower risk of 264 diseases than inactive people. The study found that concentrating physical activity into longer sessions on just 1 or 2 days a week is as beneficial as spreading activity more evenly across the week.
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About Mass General Brigham
Mass General Brigham is a healthcare system that brings together the best minds in medicine to improve the lives of patients around the world. The system is made up of 16 hospitals, including 5 ranked among the nation’s best by US News & World Report: Massachusetts General Hospital, Brigham and Women’s Hospital, Mass Eye and Ear, McLean Hospital and Spaulding Rehabilitation, as well as community and specialty care centres, health insurance plans, physician networks, home care and long-term care services.
Mass General Brigham is a nonprofit organisation committed to patient care, teaching and research. With an annual budget of almost 2 billion dollars, Mass General Brigham’s research programme is one of the largest in the U.S. and funds more than 2,700 clinical trials. It is also one of the country’s leading biomedical research organisations and the principal teaching affiliate of Harvard Medical School.
