Tag: sedentary time

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Breaking up Sedentary Time with Light Exercise Lowers BP

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More than six sedentary hours per day from childhood through young adulthood may cause an excess increase of 4mmHg in systolic blood pressure, a new study shows. Continuously engaging in light physical activity (LPA) significantly mitigated the rise in blood pressure – while longer bouts of more vigorous exercise . The results were published in the prestigious Journal of Cachexia, Sarcopenia and Muscle.

In the present study, a collaboration between the Universities of Bristol and Exeter, and the University of Eastern Finland, 2513 children drawn from the Children of the 90s cohort were followed up from age 11 until 24 years. At baseline, the children spent six hours per day sedentary, six hours per day engaging in LPA, and approximately 55 minutes per day in moderate-to-vigorous physical activity (MVPA). At follow-up in young adulthood, nine hours per day were spent sedentary, three hours per day in LPA, and approximately 50 minutes per day in MVPA. 

The average blood pressure in childhood was 106/56mmHg which increased to 117/67mmHg in young adulthood, partly due to normal physiological development. Persistent increase in sedentary time from age 11 through 24 years was associated with an average of 4mmHg excess increase in systolic blood pressure. Participating in LPA from childhood lowered the final level by 3mmHg, but engaging in MVPA had no blood pressure-lowering effect. 

“Furthermore, when 10 minutes out of every hour spent sedentary was  replaced with an equal amount of LPA from childhood through young adulthood in a simulation model, systolic blood pressure decreased by 3mmHg and diastolic blood pressure by 2mmHg. This is significant, as it has been reported in adults that a systolic blood pressure reduction of 5mmHg decreases the risk of heart attack and stroke by ten percent,” says Andrew Agbaje, an award-winning physician and associate professor (docent) of Clinical Epidemiology and Child Health at the University of Eastern Finland.

The current study is the largest and the longest follow-up of accelerometer-measured movement behaviour and blood pressure progression in youth in the world. Measurements of blood pressure, sedentary time, LPA and, MVPA were taken at ages 11, 15, and 24 years. The children’s fasting blood samples were also repeatedly measured for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, glucose, insulin, and high-sensitivity C-reactive protein. Heart rate, socio-economic status, family history of cardiovascular disease, smoking status as well as dual-energy X-ray absorptiometry measured fat mass and lean mass were accounted for in the analyses. 

“We have earlier shown that elevated blood pressure and hypertension in adolescence increase the risk of premature cardiac damage in young adulthood. The identification of childhood sedentariness as a potential cause of elevated blood pressure and hypertension with LPA as an effective antidote is of clinical and public health significance. Several MVPA-based randomised controlled trials in the young population have been unsuccessful in lowering blood pressure. We noted an MVPA-induced increase in muscle mass enhanced a physiologic increase in blood pressure explaining why earlier MVPA-based randomised clinical trials were unsuccessful,” says Agbaje.

Source: University of Eastern Finland

Categories : Cardiovascular Disease ExerciseTags :

High Cholesterol from Childhood Sedentary Time could be Reversed with Light Exercise

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Photo by Victoria Akvarel on Pexels

Increased sedentary time in childhood can raise cholesterol levels by two thirds as an adult, but a new study has found light physical activity may completely reverse the risks and is far more effective than moderate-to-vigorous physical activity.

The study was published in The Journal of Clinical Endocrinology & Metabolism. Researchers used data from the University of Bristol study Children of the 90s (also known as the Avon Longitudinal Study of Parents and Children), which included 792 children aged 11 years who were followed up until the age of 24.

Results from this study found that accumulated sedentary time from childhood can increase cholesterol levels by two thirds (67%) by the time someone reaches their mid-twenties. Elevated cholesterol and dyslipidaemia from childhood and adolescence have been associated with premature death in the mid-forties and heart problems such as subclinical atherosclerosis and cardiac damage in the mid-twenties.

Healthy lifestyles are considered important in the prevention of dyslipidaemia and one of the primary ways of lowering cholesterol, apart from diet, is movement behaviour. For the first time, this study objectively examined the long-term effects of sedentary time, light physical activity, and moderate-to-vigorous physical activity on childhood cholesterol levels.

The World Health Organization currently recommends children and adolescents should accumulate on average 60 minutes of moderate-to-vigorous physical activity a day and reduce sedentary time but have limited guidelines for light physical activity. Yet this new study and other recent studies has found light physical activity – which includes exercises such as long walks, house chores, or slow dancing, swimming, or cycling – is up to five times more effective than moderate-to-vigorous physical activity at promoting healthy hearts and lowering inflammation in the young population.

Dr Andrew Agbaje from the University of Exeter led the study and said: “These findings emphasise the incredible health importance of light physical activity and shows it could be the key to preventing elevated cholesterol and dyslipidaemia from early life. We have evidence that light physical activity is considerably more effective than moderate-to-vigorous physical activity in this regard, and therefore it’s perhaps time the World Health Organization updated their guidelines on childhood exercise — and public health experts, paediatricians, and health policymakers encouraged more participation in light physical activity from childhood.”

During the research, accelerometer measures of sedentary time, light physical activity, and moderate-to-vigorous physical activity were collected at ages 11, 15, and 24 years. High-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, and total cholesterol were repeatedly measured at ages 15, 17, and 24 years. These children also had repeated measurement of dual-energy X-ray absorptiometry assessment of total body fat mass and muscle mass, as well as fasting blood glucose, insulin, and high sensitivity C-reactive protein, with smoking status, socio-economic status, and family history of cardiovascular disease.

During the 13-year follow-up, sedentary time increased from approximately six hours a day to nine hours a day. Light physical activity decreased from six hours a day to three hours a day while moderate-to-vigorous physical activity was relatively stable at around 50 minutes a day from childhood until young adulthood. The average increase in total cholesterol was 0.69 mmol/L. It was observed without any influence from body fat.

An average of four-and-a-half hours a day of light physical activity from childhood through young adulthood causally decreased total cholesterol by (-0.53 mmol/L), however, body fat mass could reduce the effect of light physical activity on total cholesterol by up to 6%. Approximately 50 minutes a day of moderate-to-vigorous physical activity from childhood was also associated with slightly reduced total cholesterol (-0.05 mmol/L), but total body fat mass decreased the effect of moderate-to-vigorous physical activity on total cholesterol by up to 48%. Importantly, the increase in fat mass neutralised the small effect of moderate-to-vigorous physical activity on total cholesterol.

Source: University of Exeter

Categories : Cardiovascular Disease ExerciseTags :

Cutting Down on Sedentary Time Reduces Cardiovascular Risk

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Cutting down daily sedentary time can have a positive effect on the risk factors of cardiovascular disease and type 2 diabetes in as little as three months, according to a study published in the Journal of Science and Medicine in Sport. The study findings suggest that simply one hour less sitting daily and increasing light physical activity can help in the prevention of these diseases.

Regular exercise is well known to be beneficial in weight management and prevention of chronic diseases. However, many adults do not meet the weekly recommendation of 2.5 hours of moderate-intensity exercise, and the majority of the day is typically spent sitting.

In an intervention study, researchers investigated whether health benefits can be achieved by reducing daily sedentary time during a three-month intervention period. The research participants were sedentary and physically inactive working-age adults with an increased risk of type 2 diabetes and cardiovascular diseases.

The researchers compared two groups: the intervention group was guided to reduce their sitting time by one hour per day by increasing standing and light-intensity physical activity, while the control group was instructed to maintain their usual habits and sedentary lifestyle.

“What makes our research design unique is that sedentary time and physical activity of both groups were measured with accelerometers throughout the entire three-month period, whereas in earlier studies activity has typically been measured only for a few days at the beginning and end of the study period. This makes it possible to receive more information on the actual behaviour changes over a longer time period,” explained  Doctoral Candidate Taru Garthwaite from the University of Turku in Finland.

The intervention group reduced sedentary time by 50 minutes per day on average, mainly by increasing the amount of light- and moderate-intensity physical activity. Over the three-month period, the researchers observed benefits in health outcomes related to blood sugar regulation, insulin sensitivity and liver health in the intervention group.

“It is an encouraging thought that health benefits can be achieved by reducing the time spent sitting and increasing the amount of even light-intensity physical activity. For many, this may be an easier starting point than increasing actual exercise,” said Garthwaite.

People who do not meet the weekly physical activity recommendations atre the most likely to benefit the most from replacing sedentary time with light physical activity. However, reducing sedentary time is probably not enough in itself to prevent diseases if the person has several risk factors of diabetes and cardiovascular diseases.

Garthwaite stressed the encouraging nature of the findings: “Reducing the time spent sitting might still slow down the development of these diseases, but greater benefits can of course be gained by increasing the amount or intensity of physical activity in addition to sitting less.”

The researchers next aim to study how changes in daily activity and sedentary time affect energy metabolism and body composition in addition to the risk factors of diabetes and cardiovascular diseases over a six-month study period.

Source: University of Turku