Monthly Archives: December 2014

High fitness levels reduce hypertension risk


While being physically fit is beneficial in and of itself, researchers now report that people with high levels of fitness are less likely to develop high blood pressure – also referred to as hypertension – a risk factor for cardiovascular disease.

The study, published in the Journal of the American Heart Association, examined the association of fitness with hypertension among participants undergoing treadmill stress tests to rule out ischemia as a cause of chest pain or shortness of breath.

“If you’re exercising and you’re fit, your chances of developing hypertension are much less than someone else who has the same characteristics but isn’t fit,” says Dr. Mouaz H. Al-Mallah, senior author of the study.

Normal blood pressure is below 120/80 mm Hg – the first number (systolic measurement) represents peak pressure in the arteries and the second number (diastolic measurement) represents minimum pressure in the arteries. Blood pressure is considered to be high when it is greater than 140/90 mm Hg.

There are two types of hypertension. While secondary hypertension appears suddenly and is caused by underlying conditions such as kidney or thyroid problems, primary hypertension has no identifiable cause and develops gradually over the course of many years.

In the US, hypertension affects 1 in 3 adults. According to the American Heart Association (AHA), 78 million people in the country have been diagnosed with the condition.

“Hypertension is associated with a lot of other illnesses and adds significantly to health care costs,” explains Dr. Al-Mallah, “so we need to know how we can reduce it.”

Measuring physical fitness and high blood pressure

The researchers assessed 57,284 participants from the Henry Ford Exercise Testing (FIT) Project, from 1991-2009, taking treadmill stress tests. Of these, 35,175 participants had a history of hypertension.

The team measured the physical fitness of the participants by estimating how much oxygen their bodies used per kg ofbody weight per minute, and thus how much energy they burned in metabolic equivalents (METs).

With 1 MET representing the amount of energy expended by the body at rest, a large number of METs reflects a high-intensity workout.

The researchers observed that participants whose most intense exercise was less than 6 METs had more than a 70% likelihood of having hypertension at the start of the study. Conversely, participants whose maximal exercise output was 12 METs were less than 50% likely to have hypertension.

During the stress test, participants who managed to reach 12 METs or more were 20% less likely to develop hypertension compared with participants who reached less than 6 METs.

A total of 8,053 new cases of hypertension were reported in participants’ medical records and administrative claims during the study’s follow-up period. Of these new cases, 49% were among participants with the lowest fitness (less than 6 METs), and only 21% were among participants with the highest fitness (more than 12 METs).

Fitness: a ‘strong predictor’ of hypertension

Although the study uses a large and diverse population sample, the participants were all originally referred for a stress test, indicating that their initial cardiovascular disease risk would be greater than that of the general population, potentially hindering the generalizability of the findings. The study was also limited by a lack of measuring incidental hypertension in a clinical setting.

Dr. Al-Mallah states that further study is required in order to determine how increasing and decreasing fitness levels affect the risk of hypertension over time. Physical activity was not formally assessed in the study, and this could be addressed in future research as well.

Hypertension is a major risk factor for cardiovascular disease, the number one cause of premature mortality in the developed world. High levels of exercise have been associated with protecting the body from certain health conditions, and now this study suggests adding hypertension to the list.

“Fitness is a strong predictor of who develops hypertension and who does not,” says Dr. Al-Mallah. “This is a clear message to everyone: patients, physicians and lawmakers. It’s very important to be fit.”

Medical News Today also recently reported on a study suggesting that sugars may contribute more to hypertension risk than salt.

Written by James McIntosh



‘Obesity can reduce life by up to 8 years’


Life expectancy can be reduced by up to 8 years by obesity, which can also cause adults to lose as much as 19 years of healthy life if it leads to type 2 diabetes and cardiovascular disease. A study published in The Lancet Diabetes & Endocrinology examines the issue.


The researchers behind the study analyzed data from the US National Health and Nutrition Examination Survey (NHANES), creating a disease-simulation model to estimate the risk of adults of different body weightdeveloping diabetes and cardiovascular disease.

From this, the researchers then calculated the extent to which overweight and obesity may contribute to both years of life lost and years of healthy life lost in American adults aged between 20 and 79 years old, in comparison to people of normal weight.

They found that people who were overweight (BMI 25-30 kg/m2) were estimated to lose up to 3 years of life, depending on age and gender. Individuals classed as obese (BMI 30-35 kg/m2) were calculated to lose up to 6 years, and people classed as very obese (BMI 35 kg/m2 or more) could lose up to 8 years of life.

According to the study, excess weight had the greatest impact on lost years of life among the young and dropped with increasing age.

Obesity can cause the loss of up to 19 ‘healthy life-years’

As well as reducing life expectancy, carrying extra weight was also found to reduce “healthy life-years,” which were defined in the study as years free of obesity-linked cardiovascular disease and diabetes.

Young adults aged between 20 and 29 showed the highest losses of healthy life-years, adding up to around 19 lost years for very obese people. Among people who were overweight or obese, the researchers calculated that two to four times as many healthy life-years were lost than total years of life lost.

Dr. Steven Grover, lead author and professor of medicine at McGill University and a clinical epidemiologist at the Research Institute of the McGill University Health Centre in Canada, explains the findings:

“The pattern is clear. The more an individual weighs and the younger their age, the greater the effect on their health, as they have many years ahead of them during which the increased health risks associated with obesity can negatively impact their lives.

These clinically meaningful calculations should prove useful for obese individuals and health professionals to better appreciate the scale of the problem and the substantial benefits of a healthier lifestyle, including changes to diet and regular physical activity.”

This week on Medical News Today, we also looked at a study published in The BMJ that found obesity during early pregnancy is a risk factor for infant mortality.

The researchers behind that study found that infant mortality was “moderately increased” among overweight and mildly obese mothers (BMI 25-35 kg/m2) compared with mothers of a normal weight; but among more obese mothers (BMI over 35 kg/m2), the risk of infant mortality was more than doubled.

We also reported on a study in the journal Preventing Chronic Disease that found women – particularly black women – are more at risk of increased obesity if they work jobs that involve a lot of sitting down.

Written by David McNamee



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