Heart health and physical activity

New research, appearing in the European Heart Journal, suggests that lack of physical activity can drastically increase the risk of a heart attack in the long-term, even if there are no symptoms at present.
running and heart fitness
Exercise that raises the heart rate, such as running, may cut heart attack risk by half, suggests a new study.

Cardiorespiratory fitness describes the body’s ability to deliver oxygen to the muscles when we are engaged in physical activity. Specifically, the term refers to “the efficiency of the heart, lungs and vascular system.”

A significant body of research has linked cardiorespiratory fitness with a variety of positive health outcomes, ranging from preventing cardiovascular disease and all-cause mortality to staving off diabetes and improving insulin resistance.

However, most of these previous studies have relied on the participants’ self-reported levels of fitness.

New research uses more precise methods of measuring cardiorespiratory fitness and highlights another one of its benefits.

Higher fitness levels can halve the risk of heart attack, the new study finds. Conversely, suggest the researchers, poor fitness levels can raise future risk even in the absence of warning symptoms in the present.

Bjarne Nes, from the Norwegian University of Science and Technology’s Cardiac Exercise Research Group in Trondheim, is the corresponding and last author of the study.

Studying fitness levels and heart attack risk

Nes and his colleagues analyzed the cardiorespiratory fitness of more than 4,500 people who took part in an extensive health survey called HUNT3.

None of the participants had a history of cardiovascular disease, lung disease, cancer, or high blood pressure at the start of the study.

Just over 50 percent of the participants were women, and more than 80 percent of all of them were at “low risk” of developing cardiovascular disease over a 10-year period.

The scientists used a “gold-standard method” — or maximum oxygen uptake — to directly measure the participants’ fitness levels.

Maximum oxygen uptake refers to the maximum amount of oxygen the body can absorb during exercise. According to Nes, it is “the most precise measure of fitness.”

High fitness halves the risk of heart attack

By the end of the study, 147 of the participants had heart attacks or had developed angina pectoris — two conditions caused by blocked or narrowed coronary arteries.

The analysis by the researchers revealed a correlation between declining cardiovascular risk and increased fitness levels.

“Even among people who seem to be healthy, the top 25 percent of the most fit individuals actually have only half as high a risk as the least fit 25 percent,” reports Nes.

Furthermore, even a small improvement in cardiorespiratory fitness saw significant benefits for heart health. Namely, each fitness increase of 3.5 points correlated with a 15 percent lower risk of heart attack or angina.

“We found a strong link between higher fitness levels and a lower risk of heart attack and angina pectoris over the 9 years following the measurements that were taken,” says Nes.

“We know that patients with low oxygen uptake are at increased risk of premature death and cardiovascular disease,” he continues.

Our study shows that poorer fitness is an independent risk factor for coronary artery disease, even among healthy women and men who are relatively fit.”

Bjarne Nes

‘Use training as preventive medicine’

Dr. Jon Magne Letnes, the study’s first author, also further comments on the findings. “Our results should encourage people to use training as preventive medicine,” Dr. Letnes says.

“A few months of regular exercise that gets you out of breath can be an effective strategy for reducing the risk of cardiovascular disease.”

Dr. Letnes explains that cardiorespiratory fitness offers insights into so much more than just endurance to exercise.

“Fitness isn’t just a measure of how much you’ve trained in your life, but it also tells you what kind of genes you have,” he says.

“Other factors like obesity may also affect fitness. So we measure a lot of the body’s functions, and from other studies, we know that both genes and physical activity play a role in how your heart and blood vessels function,” Dr. Letnes explains.

The study’s first author thinks doctors should consider fitness measurements when evaluating heart disease risk.

“Although it may be inconvenient and difficult to measure oxygen uptake at the doctor’s office, some simple and relatively accurate calculators exist that can provide a good estimate of fitness and disease risk,” he advises.

Body Mass Index Measurement

This post deals with measuring Body Mass Index (BMI) for adults, children, and teens. Body mass index, or BMI, is a measure of body size. It combines a person’s weight with their height. The results of a BMI measurement can give an idea about whether a person has the correct weight for their height. 

BMI (Body Mass Index) is a screening tool that can indicate whether a person is underweight or if they have a healthy weight, excess weight, or obesity. If a person’s Body Mass Index is outside of the healthy range, their health risks may increase significantly.

Carrying too much weight can lead to a variety of health conditions, such as type 2 diabetes, high blood pressure, and cardiovascular problems.  In a previous post, we offered five simple exercises which can help a person achieve some of their weight goals.

A weigh that is too low can increase the risk of malnutrition, osteoporosis, and anemia. The doctor will make suitable recommendations.

Body Mass Index does not measure body fat directly, and it does not account for age, sex, ethnicity, or muscle mass in adults.

However, it uses standard weight status categories that can help doctors to track weight status across populations and identify potential issues in individuals.

BMI (Body Mass Index) in adults

Body Mass Index calculator shows healthy weight
A BMI chart or calculator can show a person if they have a healthy weight.

Calculating BMI involves measuring a person’s height and body weight.

 

Metric

  • To calculate BMI in metric units, use the following method: BMI = kg/m2
  • So, to calculate an adult’s BMI: Divide their weight in kilograms (kg) by the square of their height in meters (m2)

Since most people measure height in centimeters (cm), divide height in cm by 100 to get height in meters.

Imperial

  • When using imperial units, the formula is: BMI = lbs x 703/in2
  • In other words: Multiply a person’s weight in pounds (lbs) by 703. Then divide by their height in inches, squared (in2)

To avoid using the math, a person can use a calculator or a chart to find their BMI.

BMI calculator

Enter height or weight in either imperial or metric measurements to find your BMI.

1) Metric BMI Calculator

2) Imperial BMI Calculator

BMI charts

People can also work out their BMI using a chart. Click here to see a chart provided by the National Heart, Lung, and Blood Institute (NHLBI).

Locate your height in inches on the side of the chart, then look across to find your body weight in pounds. Scan to the top to see if the result corresponds to a normal weight, overweight, or obesity.

Understanding the results

The following table shows the standard weight status categories associated with BMI ranges for adults.

BMI Weight status
Below 18.5 Underweight
18.5–24.9 Healthy
25.0–29.9 Overweight
30.0 and above Obese

BMI of less than 18.5

A BMI of less than 18.5 indicates that you are underweight, so you may need to put on some weight. You are recommended to ask your doctor or a dietitian for advice.

BMI of 18.5–24.9

A BMI of 18.5-24.9 indicates that you are at a healthy weight for your height. By maintaining a healthy weight, you lower your risk of developing serious health problems.

BMI of 25–29.9

A BMI of 25-29.9 indicates that you are slightly overweight. You may be advised to lose some weight for health reasons. You are recommended to talk to your doctor or a dietitian for advice.

BMI of over 30

A BMI of over 30 indicates that you are heavily overweight. Your health may be at risk if you do not lose weight. You are recommended to talk to your doctor or a dietitian for advice.

BMI in children and teens

In adults, BMI values are not linked to age and are the same for both sexes.

However, measuring Body Mass Index in children and teens is slightly different. Girls and boys develop at different rates and have different amounts of body fat at different ages. For this reason, BMI measurements during childhood and adolescence take age and sex into consideration.

Doctors and other health professionals do not categorize children by healthy weight ranges because:

  • they change with each month of age
  • male and female body types change at different rates
  • they change as the child grows taller

Doctors calculate BMI for children and teens in the same way as they do for adults, by measuring height and weight. Then they locate the BMI number and person’s age on a sex-specific BMI-for-age chart. This will indicate whether the child is within a healthy range.

Calculator and charts for child and teen Body Mass Index

The Centers for Disease Control and Prevention (CDC) have produced a calculator that provides BMI and the corresponding BMI-for-age percentile on a CDC growth chart for children and teens.

First, click here for the calculator.

Next, use the charts to see if a child’s weight is suitable for their age.

Click here for the charts:

What do the results mean?

The following categories explain the meaning of the results:

Weight status category Percentile range
Underweight Below the 5th percentile
Healthy weight 5th percentile to less than the 85th percentile
Overweight 85th to less than the 95th percentile
Obesity Equal to or greater than the 95th percentile

How doctors use BMI

BMI is not accurate enough to use as a diagnostic tool, but it can screen for potential weight problems in adults and children.

If someone has a high or low BMI, a doctor or other healthcare professional might then consider other factors, such as:

  • skinfold thickness measurements, which indicate how much fat is in the body in adults and children
  • evaluations of diet and physical activity
  • discuss any family history of cardiovascular disease and other health problems
  • recommend other appropriate health screenings

The doctor or healthcare professional can then make diet and exercise recommendations based on these results.

Health risks of extra weight

Excess weight has the following effects on the body:

  • It increases how hard the heart has to work.
  • It raises blood pressure, blood cholesterol and triglyceride levels.
  • It lowers high-density lipoprotein (HDL), or good cholesterol levels.
  • It can make diabetes and other health problems more likely.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), carrying extra weight can increase the risk of the following conditions:

  • hypertension, or high blood pressure
  • dyslipidemia, which involves high LDL cholesterol, low HDL cholesterol, or high levels of triglycerides
  • type 2 diabetes
  • coronary heart disease
  • stroke
  • gallbladder disease
  • osteoarthritis
  • sleep apnea and respiratory problems
  • some cancers, including endometrial, breast and colon cancer

Carrying extra weight as a child or teenager can also pose significant health risks, both during childhood and into adulthood.

As with adult obesity, childhood obesity increases the risk of various health problems, including cardiovascular disease, diabetes, and sleep apnea.

The American Heart Association (AHA), point out that children with a high BMI also have a higher risk of:

Benefits of a healthy weight

Walking with the family helps Body Mass Index levels
Walking with family or friends can be an enjoyable way of keeping fit and preventing unwanted weight gain.

Apart from reducing the risk of the health conditions, maintaining a healthy weight offers additional benefits:

  • fewer joint and muscle pains
  • increased energy and ability to join in more activities
  • improved regulation of bodily fluids and blood pressure
  • reduced burden on the heart and circulatory system
  • improved sleep patterns

Other measures of a healthy body

BMI is a useful tool, but it cannot identify whether a person’s weight is made up of muscle or fat.

For example, an athlete with a lot of muscle tissue may have a higher BMI than a person who is not very active. But, this does not mean that the athlete is overweight or unhealthy.

In addition, cardiovascular disease and high blood pressure are more likely to occur in people who have additional fat — known as visceral fat — around their middle rather than their hips.

Other measures of body size include waist-hip ratio, waist-to-height ratio, and body composition, which measures body fat and lean body mass. These measurement systems focus more on the amount of fat a person has and its distribution around the body.

Together with BMI, these additional measures can help to assess more accurately the health risks associated with an individual’s weight.

Takeaway

Body Mass Index can be a useful screening tool for predicting certain health risks. However, people should use it with caution, as it does not take other factors — such as activity levels and body composition — into account.

For children and teens, it is important to include their age and sex when taking a BMI measurement, because their bodies continuously change as they develop.