Short bursts of exercise at home good for the heart

reposted from: http://www.nhs.uk/news/2013/February/Pages/Short%20bursts-of-exercise-good-for-heart.aspx

crabsallover highlights, key points, comments / links.

Short bursts of exercise, such as raking the lawn and climbing the stairs, are an excellent way of warding off health problems such as high blood pressure, high cholesterol and diabetes, the Daily Mirror and many global media outlets reported.

The news is based on the results of a cross-sectional study which suggested that even less than 10 minutes of moderate or vigorous activity, such as climbing stairs, ‘count’ and may be as beneficial as longer periods of exercise.

This useful and well-conducted study measured the physical activity of more than 6,000 adults, in addition to measuring various health markers such as blood fats, blood sugar and blood pressure, that are known to be risk factors for chronic conditions including diabetes and heart disease.

The study found that performing moderate or vigorous activity of any duration – either short bursts of less than 10 minutes or for longer – was associated with improved measurements of several cardiovascular risk factors.

The study suggests that even people who do not have time to go to the gym or an exercise class can get many of the health benefits of exercise from adopting an ‘active’ lifestyle.

While the study cannot directly prove cause and effect, it would suggest that any moderate or vigorous exercise you can fit in during the course of a day, benefits your health.

10-minute exercise programmes

NHS Choices has produced a series of 10-minute exercise programmes you can do in the comfort of your own home:

• 10-minute home cardio workout
• 10-minute legs, bums and tums home workout
• 10-minute home toning workout

Don’t forget to warm up before, and then cool down after, exercising.

Where did the story come from?

The study was carried out by researchers from Bellarmine University and Oregon State University. The source of funding for this study was not declared.

The study was published in the peer-reviewed American Journal of Health Promotion.

This study was covered by the Daily Mirror and the Mail Online. Although the gist of the story is correct, the researchers looked at short bursts of moderate and vigorous physical activity, rather than the ‘light exercise’ reported in the Mail Online.

How active should I be?

To stay healthy, adults aged 19-64 should try to be active daily and should do:

• at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity such as cycling or fast walking every week, and
• muscle-strengthening activities on two or more days a  week that work all major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms)

Read more about physical activity guidelines for adults

What kind of research was this?

This cross-sectional study aimed to determine whether short bursts of physical activity were associated with a decreased risk of metabolic syndrome.

Metabolic syndrome is a term used to describe a combination of related risk factors for chronic conditions such as heart disease and type 2 diabetes – these factors include high waist circumference, blood fats, blood sugar and blood pressure.

The researchers also looked at some additional biological markers known to be risk factors for cardiovascular disease.

They looked at whether there were any differences in risk factors for short bursts of activity versus more prolonged bursts.

Cross-sectional studies have a inherent limitation as they cannot prove causation (a direct cause and effect), they can only highlight possible associations.

So in this case, the researchers cannot conclude that it is the short bursts of activity directly affecting the biological markers measured.

Also, because participants aren’t followed over time we don’t know what came first, so we don’t know:

• if people who exercise a certain way are healthier
• if people who are healthier exercise a certain way

What did the research involve?

The researchers used data collected as part of the US National Health and Nutrition Examination Survey, which collects annual health and nutrition data on a random sample of US citizens. For this study, data from 6,321 non-pregnant adults with data on physical activity from the 2003-2004 and 2005-2006 cycles was used.

A participant’s physical activity was determined by collecting data using an accelerometer. Accelerometers measure the participant’s change in velocity over time (acceleration) allowing the intensity of physical activity to be measured, as well as the duration.

Participants had data on physical activity for at least four days, and at least 10 hours each day. The researchers classified the intensity of physical activity into moderate or vigorous using cut-offs for accelerometry readings.

The researchers also classified activity levels by duration, into two main groups:

• less than 10 minutes duration (‘nonbout’)
• more than 10 minutes duration (‘bout’)

Each period of activity was terminated if accelerometry readings fell below the cut off for three minutes or more.

The researchers also calculated whether a participant met physical activity guidelines, defined as engaging in 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity or some combination of the two per week, and whether a participant met the criteria by only performing short, less than 10 minute duration ‘nonbout’ periods of activity.

The US National Health and Nutrition Examination Survey also collected data on a participant’s cardiovascular risk factors, including:

• metabolic syndrome – defined as having three or more of the following symptoms: a high waist circumference, a high level of triglycerides (a type of fat), low levels of high-density (‘good’) cholesterol, elevated blood pressure, elevated fasting blood sugar
• systolic and diastolic blood pressure
• blood levels of C-reactive protein (an inflammatory marker), high-density cholesterol, low-density (‘bad’) cholesterol, total cholesterol and blood sugar
• anthropometric measurements including waist circumference, skinfold thickness and body mass index (BMI)

The researchers also collected data on age, gender, smoking status, race/ethnicity, current health status, and whether the participant was taking any medication.

The researchers analysed whether there was an association between short ‘nonbout’ periods of activity and longer ‘bout’ periods of activity and cardiovascular risk factors.

They also looked at whether there was any difference in risk factors when physical activity guidelines were only met by performing short ‘nonbout’ periods of activity.

In these analyses, the researchers controlled for age, gender, smoking status, race/ethnicity, and current health status.

What were the basic results?

The researchers found that on average, participants performed 23.6 minutes of moderate-to vigorous-intensity physical activity per day in short, ‘nonbout’ bursts, and 6.6 minutes in 10 minutes or longer bursts (this rather confusing figure is due to some people not doing any moderate to vigorous physical activity in bouts of 10 minutes or longer, during some days).

A total of 42.9% of participants met physical activity guidelines if nonbout physical activity was included, but only 9.7% met guidelines if only 10 minutes or longer periods only were included.

Both ‘nonbout’ and ‘bout’ physical activity were associated with a reduction in cardiovascular risk factors. The associations were strongest when enough activity was performed to meet physical activity guidelines.

The strengths of associations were generally similar for ‘bout’ and ‘nonbout’ physical activity for all risk factors measured, with the exception of BMI.

To make sure the results weren’t due to the fact that people who performed the longer periods of activity were also performing the shorter periods of activity, the researchers repeated the analyses controlling for 10 minutes or longer periods of activity.

Short ‘nonbout’ physical activity was still associated with a reduced risk of metabolic syndrome; favourable levels of C-reactive protein, high density lipoprotein cholesterol, triglycerides; and favourable sized waist circumference, skinfold thickness and BMI.

Again, the associations were strongest when enough ‘nonbout’ physical activity was performed to meet the physical activity guidelines.

Finally, the researchers compared the mean levels of biological markers in people meeting the physical activity guidelines solely through performing short ‘nonbout’ periods of physical activity and those meeting guidelines by performing longer periods of activity.

There was no statistical difference between the level of any marker except for BMI. Participants who met guidelines through longer periods of activity had significantly lower body mass indices (25.85) than those meeting guidelines through short periods of activity (27.49, p<0.0001).

How did the researchers interpret the results?

The researchers conclude that these results show that “with the exception of BMI, meeting physical activity guidelines using an ‘active lifestyle’ approach (nonbout activity) as opposed to a more structured exercise approach (bout activity) resulted in similar health outcomes.”

They suggest that “to reduce levels of adult adiposity (body fatness), adults are encouraged to engage in bouts of physical activity of at least 10 minutes in duration; however, for other health outcomes, an active lifestyle approach (for example, climbing a flight of stairs vs. taking the elevator), particularly of vigorous intensity, may be beneficial for initiating physical activity behaviour among inactive adults as well as being sufficient to elicit improvements in health parameters.”

Conclusion

The results of this study suggests that even short periods of physical activity ‘count’ and are associated with improved levels of several risk factors for cardiovascular disease. The study found that the strength of this association was generally as strong for short periods of activity as longer periods of activity.

This study has strengths and weaknesses. The strengths are that both physical activity and the levels of the biological markers were measured objectively, and did not rely on self-reporting, and that it was performed using a large sample of US adults.

However, it was a cross-sectional study, and cross-sectional studies have the limitation that they cannot show causation, in this case, the researchers cannot conclude whether it is the short bursts of activity that affect the biological markers measured.

Also, because participants aren’t followed over time we don’t know what came first, so we don’t know if people who exercise a certain way are healthier or if people who are healthier exercise a certain way.

However, overall this study supports the suggestion that any level of physical activity is better than no activity.

Even if you don’t feel ready to join your local gym, you can still begin making changes to your lifestyle today to improve your activity levels – read more about how you can get fitter without the gym.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links to the headlines

Well, I'll go to the foot of the stairs! Light exercise around the house is as good for your heart as workout. Daily Mirror, January 31 2013

Forget the gym and try the stairs! Short bursts of exercise are just as beneficial as a regular workout. Daily Mail, January 31 2013

Taking the Stairs, Raking Leaves May Have Same Health Benefits as a Trip to the Gym. Sciencedaily.com, published online January 28 2013

Links to the science

Loprinzi PD, Cardinal BJ. Association Between Biologic Outcomes and Objectively Measured Physical Activity Accumulated in >10-Minute Bouts and <10-Minute Bouts. American Journal of Health Promotion. Published online January 2013

High plasma HDL cholesterol is NOT associated with reduced risk of myocardial infarction

reposted from: http://www.lancet.com/journals/lancet/article/PIIS0140-6736(12)60312-2/fulltext?_eventId=login

crabsallover highlights, key points, comments / links.

Background

High plasma HDL cholesterol is associated with reduced risk of myocardial infarction, but whether this association is causal is unclear. Exploiting the fact that genotypes are randomly assigned at meiosis, are independent of non-genetic confounding, and are unmodified by disease processes, mendelian randomisation can be used to test the hypothesis that the association of a plasma biomarker with disease is causal.

Methods

...

Findings

...

Interpretation

Some genetic mechanisms that raise plasma HDL cholesterol do not seem to lower risk of myocardial infarction. These data challenge the concept that raising of plasma HDL cholesterol will uniformly translate into reductions in risk of myocardial infarction.

Discusssion

In summary, our results showed that polymorphisms related to plasma LDL cholesterol were consistently associated with risk of myocardial infarction, whereas this was not the case for variants related to plasma HDL cholesterol. A polymorphism in the endothelial lipase gene and a genetic score of 14 common SNPs that specifically raised HDL cholesterol were not associated with myocardial infarction, suggesting that some genetic mechanisms that raise HDL cholesterol do not lower risk of myocardial infarction. Hence, interventions (lifestyle or pharmacological) that raise plasma HDL cholesterol cannot be assumed ipso facto to lead to a corresponding benefit with respect to risk of myocardial infarction.

Cardiovascular Disease Risk Prediction Charts

reposted from: http://heartuk.org.uk/health-professionals/resources/risk-charts

crabsallover highlights, key points, comments / links.

Risk charts

How to use the Cardiovascular Disease Risk Prediction Charts* for Primary Prevention

These charts are for estimating cardiovascular disease (CVD) risk (non-fatal myocardial infarction [MI] and stroke, coronary and stroke death and new angina pectoris) for individuals who have not already developed coronary heart disease (CHD) or other major atherosclerotic disease. They are an aid to making clinical decisions about how intensively to intervene on lifestyle and whether to use antihypertensive, lipid lowering medication and aspirin. The use of these charts is not appropriate for the following patients groups.

• Those with: CHD or other major atherosclerotic disease 
• Familial hypercholesterolaemia or other inherited dyslipidaemias 
• Chronic renal dysfunction 
• Type 1 and 2 diabetes mellitus

The charts should not be used to decide whether to introduce antihypertensive medication when blood pressure (BP) is persistently at or above 160/100 or when target organ damage (TOD) due to hypertension is present. In both cases antihypertensive medication is recommended regardless of CVD risk.

Similarly the charts should not be used to decide whether to introduce lipid-lowering medication when the ratio of serum total to high density lipoprotein (HDL) cholesterol exceeds 7. Such medication is generally then indicated regardless of estimated CVD risk.

To estimate an individual’s absolute 10 year risk of developing CVD choose the table for his or her gender, smoking status (smoker/non-smoker) and age. Within this square define the level of risk according to the point where the coordinates for systolic blood pressure (SBP) and the ratio of total cholesterol to HDL-cholesterol meet. If no HDL cholesterol result is available, then assume this is 1.00mmol/l and the lipid scale can be used for total serum cholesterol alone.

Higher risk individuals (red areas) are defined as those whose 10 year CVD risk exceeds 20%, which is approximately equivalent to the CHD risk of >15% over the same period indicated by the previous version of these charts. As a minimum those at highest CVD risk (greater than 30% shown by the line within the red area) should be targeted and treated now. When resources allow, others with a CVD risk of >20% should be progressively targeted.

The chart also assists in the identification of individuals whose 10 year CVD risk moderately increased in the range 10-20% (orange area) and those in whom risk is lower than 10% over 10 years (green area).

Smoking status should reflect lifetime exposure to tobacco and not simply tobacco use at the time of assessment. For example, those who have given up smoking within 5 years should be regarded as current smokers for the purposes of the charts.

The initial BP and the first random (non-fasting) total cholesterol and HDL cholesterol can be used to estimate an individual’s risk. However, the decision on using drug therapy should generally be based on repeat risk factor measurements over a period of time.

Men and women do not reach the level of risk predicted by the charts for the three age bands until they reach the ages 49, 59, and 69 years respectively. Everyone aged 70 years and over should be considered at higher risk. The charts will overestimate current risk most in the under forties. Clinical judgement must be exercised in deciding on treatment in younger patients. However, it should be recognised that BP and cholesterol tend to rise most and HDL cholesterol to decline most in younger people already possessing adverse levels. Thus untreated, their risk at the age 49 years is likely to be higher than the projected risk shown on the age-less-than 50 years chart.

These charts (and all other currently available methods of CVD risk prediction) are based on groups of people with untreated levels of BP, total cholesterol and HDL cholesterol. In patients already receiving antihypertensive therapy in whom the decision is to be made about whether to introduce lipid-lowering medication or vice versa the charts can act as a guide, but unless recent pre-treatment risk factor values are available it is generally safest to assume that CVD risk is higher than that predicted by current levels of BP or lipids on treatment.

CVD risk is also higher than indicated in the charts for:-

• Those with a family history of premature CVD or stroke (male first degree relatives aged <55 years and female first degree relatives aged <65 years) which increases the risk by a factor of approximately 1.5 
• Those with raised triglyceride levels 
• Women with premature menopause 
• Those who are not yet diabetic, but have impaired fasting glucose (6.1-6.9mmol/l) 
• In some ethnic minorities the risk charts underestimate CVD risk, because they have not been validated in these populations. For example, in people originating from the Indian subcontinent it is safest to assume that the CVD risk is higher than predicted from the charts (1.5 times). 
• The charts may be used to illustrate the direction of impact of risk factor intervention on estimated level of CVD risk. However, such estimates are crude and are not based on randomised trial evidence. Nevertheless, this approach maybe helpful in motivating appropriate intervention. 
• The charts are primarily to assist in directing intervention to those who typically stand to benefit most. 

*Cardiovascular Disease Risk Prediction Chart reproduced with permission from The University of Manchester Department of Medical Illustration, Manchester Infirmary.

LDL, HDL, Cholesterol test results

NHS UK

The government advises http://www.nhs.uk/Planners/NHSHealthCheck/Pages/Healthycholesterol.aspx

 that adults should have:

• Total cholesterol lower than 5mmol/L
• LDL cholesterol lower than 3mmol/L

LabtestOnline

What does the HDL test result mean?

reposted from: http://www.labtestsonline.org.uk/understanding/analytes/hdl/test.html

High levels of HDL cholesterol are better than low HDL cholesterol.  The higher your HDL cholesterol level, the lower risk of developing heart disease. There are two ways that HDL cholesterol values are interpreted—as a percent of total cholesterol or as a measured value.  

• Percent: If HDL is 20% of the total cholesterol, the risk of heart disease is average. If HDL is more than 20% of the total cholesterol, the risk of heart disease is less than average. This is usually expressed as a ratio of cholesterol to HDL. It is desirable for the cholesterol/HDL ratio to be less than 5.
• Measured Value: If HDL cholesterol is less than 1.0 mmol/L in men or less than 1.2 mmol/L in women, there is an increased risk of heart disease. A desirable level of HDL is greater than 1.0 mmol/L for men and greater than 1.2mmol/L for women and is associated with average risk of heart disease. A good level of HDL is 1.5 mmol/L or more and is associated with a less than average risk of heart disease.

HDL should be interpreted in the context of the overall findings from the lipid profile and in consultation with your doctor about other risk factors for heart disease.

What does the Cholesterol test result mean? 

http://www.labtestsonline.org.uk/understanding/analytes/cholesterol/test.html

The cholesterol level measured in your blood will be considered along with other risk factors for heart disease (high blood pressure, smoking etc.) when assessing your overall risk of developing heart disease. This overall assessment is what will be used to decide whether or not you require further treatment in the form of dietary changes or drugs to lower your cholesterol level.
If you are taking treatment to lower your cholesterol, the target is to lower your total cholesterol to a value less than 4 mmol/L, with a fall of around 20-25%.

What does the LDL test result mean?

http://www.labtestsonline.org.uk/understanding/analytes/ldl/test.html#what

Elevated levels of LDL indicate risk for heart disease. Treatment (with diet or drugs) for high LDL aims to lower LDL to a target value of less than 3 mmol/L.

This is especially important if you have other risk factors for heart disease. Risk factors include cigarette smoking, hypertension, low HDL (< 1 mmol/L), family history, age (male 55 or older; female 65 or older), being overweight, and failure to exercise regularly.

What is cholesterol?

Cholesterol is a fatty substance which is found in the blood. It is mainly made in the body. Cholesterol plays an essential role in how every cell in the body works. However, too much cholesterol in the blood can increase your risk of heart problems.

LDL cholesterol and HDL cholesterol

Cholesterol is carried around the body by proteins. These combinations of cholesterol and proteins are called lipoproteins. There are two main types of lipoproteins (classified by density):

• LDL (low-density lipoprotein) is the harmful type of cholesterol.
• HDL (high-density lipoprotein) is a protective type of cholesterol.

LDL carry cholesterol from the liver to cells of the body (ref) 1.019-1.063 g/ml
HDL collects cholesterol from the body's tissues, and brings it back to the liver. (ref) >1.063 g/ml HDL removes cholesterol from atheroma within arteries and transport it back to the liver for excretion or re-utilization—which is the main reason why HDL-bound cholesterol is sometimes called "good cholesterol", or HDL-C. (wiki)

Density (g/mL)	Class	Diameter (nm)	% protein	% cholesterol	% phospholipid	% triacylglycerol
>1.063	HDL	5-15	33	30	29	8
1.019-1.063	LDL	18-28	25	50	21	4

Lipoproteins in the blood, an aqueous medium, carry fats around the body. The protein particles have hydrophilic groups aimed outward so as to attract water molecules; this makes them soluble in the salt water based blood pool. Triglyceride-fats and cholesterol are carried internally, shielded from the water by the protein particle.

HDL are the smallest of the lipoprotein particles. They are the densest because they contain the highest proportion of protein. (wiki)

The American Heart Association, NIH and NCEP provides a set of guidelines for male fasting HDL levels and risk for heart disease. (wiki)

Level mg/dL	Level mmol/L	Interpretation
<40	<1.03	Low HDL cholesterol, heightened risk for heart disease, <50>
40–59	1.03–1.52	Medium HDL level
>60	>1.55	High HDL level, optimal condition considered protective against heart disease

Guidelines for fasting LDL-Cholesterol levels, estimated or measured, and risk for heart disease. As of 2003, these guidelines were:

Level mg/dL	Level mmol/L	Interpretation
<100	<2.6	Optimal LDL cholesterol, corresponding to reduced, but not zero, risk for heart disease
100 to 129	2.6 to 3.3	Near optimal LDL level
130 to 159	3.3 to 4.1	Borderline high LDL level
160 to 189	4.1 to 4.9	High LDL level
>190	>4.9	Very high LDL level, corresponding to highest increased risk of heart disease

source: wiki.

• 
  

Having too much harmful cholesterol in your blood can increase your risk of getting cardiovascular disease. The risk is particularly high if you have a high level of LDL cholesterol and a low level of HDL cholesterol.

Triglycerides

Triglycerides are another type of fatty substance in the blood. They are found in foods such as dairy products, meat and cooking oils. They can also be produced in the body, either by the body’s fat stores or in the liver. People who are very overweight, eat a lot of fatty and sugary foods, or drink too much alcohol are more likely to have a high triglyceride level.

People with high triglyceride levels have a greater risk of developing cardiovascular disease than people with lower levels.

What causes high cholesterol?

One of the causes of high blood cholesterol levels amount people in the UK is eating too much saturated fat. The cholesterol which is found in some foods such as eggs, liver, kidneys and some types of seafood eg. prawns, does not usually make a great contribution to the level of cholesterol in your blood. It is much more important that you eat foods that are low in saturated fat.
However, some people have high blood cholesterol even though they eat a healthy diet. For example, they may have inherited a condition called familial hyperlipidaemia (FH). For more information on FH, please download our booklet Reducing your blood cholesterol (see below under further information).

How can I reduce my cholesterol levels?

To help reduce your cholesterol level, you need to cut down on saturated fats and trans fats and replace them with monounsaturated fats and polyunsaturated fats. You should also reduce the total amount of fat you eat.
Eat oily fish regularly. Oily fish provides the richest source of a particular type of polyunsaturated fat known as omega-3 fats which can help to lower blood triglyceride levels and also helps prevent the blood from clotting, and help to regulate the heart rhythm.
Eat a high-fibre diet. Foods that are high in 'soluble fibre' such as porridge, beans, pulses, lentils, nuts, fruits and vegetables, can help lower cholesterol. Please see our fact sheet Fibre in our Any Questions/FAQ section.
Doing regular physical activity can help increase your HDL cholesterol (the 'protective' type of cholesterol).

Will eating sterol-enriched foods help reduce my cholesterol level?

There is evidence to show that substances called ‘plant sterols’ and ‘stanols’ may help reduce cholesterol levels. They are added to certain foods including margarines, spreads, soft cheeses and yoghurts. For more information please see our fact sheet Plant sterols and stanols in our Any Questions/FAQ section.