10-minute walk a day app to tackle 'inactivity epidemic'

crabsallover highlights, key points, comments / links.

"Health bosses say 45 per cent of over-16s are so sedentary they do not manage the health-boosting ten-minute walk," the Daily Mail reports.

The headline comes after data compiled by Public Health England (the government body tasked with improving the nation's health) found that more than 6.3 million adults aged 40 to 60 failed to achieve just 10 minutes of continuous brisk walking per month.

This is of concern as physical inactivity directly contributes to one in six deaths in the UK.

Due to this, as part of their ongoing One You campaign, Public Health England (PHE) has launched an app called Active 10, designed to encourage at least 10 minutes brisk walking a day.

While this is below the current minimum guidelines of 150 minutes of moderate exercise per week, 10 minutes per day can still bring health benefits and may serve as "baby steps" along a road that leads to more exercise and better health.

Read more advice about taking up walking as a hobby and exercise.

What is the basis for the news reports?

PHE has released evidence relating to physical activity, reinforcing the advice to do 150 minutes of moderate exercise a week. This level of activity can improve both physical and mental health as well as reduce the risk of long-term conditions such as type 2 diabetes.

Health benefits from exercise tend to increase in a dose-response relationship, meaning the more exercise, the more benefits. PHE has provided evidence that a (reduced) health benefit can still be achieved by engaging in a minimum of 10 minutes moderate exercise per day, for example by going for a brisk walk.

The report is based on the premise that there are still a huge number of adults who are physically inactive and 150 minutes a week might seem unachievable. Encouraging just 10 minutes of brisk walking a day, whereby heart rate is increased, can be a step in the right direction and still result in some health benefits compared to doing nothing at all.

PHE has launched an app called Active 10 to help achieve this goal, by setting targets, automatically seeing achievements and tracking progress over time.

Why is mid-life being targeted and what are the benefits of walking?

Adults in midlife (aged 40 to 60) are being targeted in particular, as increasing activity in this age group has a range of potential benefits, including:

• developing positive habits as physical activity begins to decline due to ageing
• preventing and helping to manage a range of health conditions at a period of high risk
• for those who are parents – influencing their children's activity levels

Walking is an activity that is both accessible and acceptable and has the potential to increase physical activity in adults. For adults aged 40-60 in the UK, walking is the most common of all physical activities, with 79% of all adults spending some time walking every month.

There are many benefits of brisk walking, including improved fitness, finding it easier to perform everyday physical activities, improvements in mood, improvements in quality of life, a healthier weight and an overall 15% reduction in risk of early death.

An individual can tell if they are briskly walking or engaging in other moderate activity as they will feel more breathless, warmer and have an increased heart rate.

PHE suggests walking could have a particularly important impact in those aged 40-60 who are also of a lower socioeconomic group. It estimates that if one in 10 in this group took up walking 10 minutes a day, 251 deaths per year could be prevented and a saving of £310m per year made in terms of preventable health costs.

However, over the past few decades, the amount of brisk walking has declined as has the length of time people spend walking. There is a need to encourage people who are walking to walk at a brisk pace, to increase how regularly people walk and to encourage those who do not walk to develop a walking habit.

How does this evidence affect you?

Current recommendations for physical activity for adults include engaging in both aerobic and strength exercises. You should still aim for the recommended minimum amount of 150 minutes of moderate exercise per week such as brisk walking or cycling and strength exercises on two or more days per week working all major muscles. Alternatively, a minimum of 75 minutes of vigorous exercise such as running or singles tennis, or a mixture of moderate and vigorous exercise, plus strength exercises twice a week is recommended.

However, if you feel this advice might be unachievable to start with, aiming for 10 minutes moderate exercise a day, such as a brisk walk, is a good start.

You can download the app to help you increase your physical activity levels and improve your health.

Links To The Headlines

Britain's laziness epidemic: How half of adults don't even go for a brisk walk once a month... with over-40s most at risk. Daily Mail, August 24, 2017

6 million middle-aged people take no exercise. The Guardian, August 24 2017

Four in ten adults fail to manage even one brisk 10 minute walk a month. The Daily Telegraph, August 24, 2017

Millions fail to walk briskly for 10 minutes a month. Sky News, August 24, 2017

Six million Brits facing health time bomb as they fail to walk even 10 minutes a MONTH. Daily Mirror, August 24, 2017

reposted from: http://www.nhs.uk/news/2017/08August/Pages/10-minute-walk-a-day-app-launched-to-tackle-inactivity-epidemic.aspx

Lack of Exercise is twice as deadly as obesity

crabsallover highlights, key points, comments / links.

How many deaths can theoretically be avoided if inactive people became more active, compared to how many could be avoided if obese people lost weight?

If activity levels were increased so that no-one was classed as inactive, then this could reduce early deaths by more than 7%. This compares to avoiding obesity, which could reduce deaths by nearly 4%.

In 2008, 676,000 deaths were attributable to physical inactivity, compared with 337,000 deaths attributable to obesity. This large study also found that among inactive individuals, even small increases in activity may be of benefit, whatever their weight or waist size.

So should we concentrate purely on physical activity and stop worrying about losing weight?

More.... http://www.nhs.uk/news/2015/01January/Pages/Inactivity-twice-as-deadly-as-obesity.aspx

Link to science (Open Access): http://ajcn.nutrition.org/content/early/2015/01/14/ajcn.114.100065.abstract?sid=6be3c78d-3af7-4b26-83b1-45e5da06d5c1

Free pdf: http://ajcn.nutrition.org/content/early/2015/01/14/ajcn.114.100065.full.pdf+html

Change4Life '150 minutes active exercise per week'

reposted from: http://www.nhs.uk/change4life/pages/get-going-every-day.aspx

crabsallover highlights, key points, comments / links.

Building activity into your day keeps your heart healthy, reduces your risk of serious illness and strengthens muscles and bones. It can also be a great way of reducing your stress levels and lifting your mood if you’re feeling down.

That means:

• Adults needs to be active for at least 150 minutes each week
• Being active means getting your heart rate up, feeling warmer (perhaps even breaking into a light sweat) and making your lungs work harder.

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

Hormesis - a small amount of 'toxin' eg exercise or Intermittent Fasting can help

reposted from: http://www.grc.nia.nih.gov/branches/lns/BestinSmallDoses.pdf - copy of New Scientist 2008 article

crabsallover highlights, key points, comments / links.

Hormesis (wikipedia) involves a biphasic response in which a small amount of a toxin has a beneficial effect whilst increasing quantities are toxic.

An example of a hormetic product is selenium which is a micronutrient and improves health at low doses but is toxic at high doses. Plants and vegetables (5 a day) and Exercise have a hormetic effect too.

A very low dose of a chemical agent may trigger from an organism the opposite response to a very high dose.

Egg Yolks study

reposted from: http://www.nhs.uk/news/2012/08august/Pages/Eating-egg-yolks-as-bad-as-smoking.aspx

crabsallover highlights, key points, comments / links.

"Eating egg yolks is as bad as smoking in speeding up coronary heart disease" the Daily Mail says, reporting that egg yolks contribute to the clogging up of arteries which, in turn, can increase the risk of heart disease.

The news is based on a Canadian study which used ultrasound to look at the fatty build-up in the arteries of around 1,200 adults who were attending a clinic because they had pre-existing risk factors for heart disease.

The adults were questioned on their smoking history, the number of egg yolks eaten per week and how long they had eaten this amount of egg yolks.

They found that a combination of smoking and egg yolk consumption was related to a fatty build-up in the arteries, which could increase the risk of heart disease as well as other conditions that can affect the heart and blood vessels (cardiovascular diseases or CVDs).

This study does contain some important limitations, such as:

• the accuracy of the participants’ recollections of their egg yolk consumption
• a lack of detailed information on how the eggs were cooked
• there may have been additional risk factors contributing to artery ‘clogging’, not assessed by the study, such as lack of exercise or alcohol consumption
• while it is reasonable to assume that fatty build-up in the neck arteries can increase the risk of heart disease, it is uncertain exactly what the increased level of risk would be

This study perhaps best supports the notion of “all things in moderation”. Eggs are a good source of protein. Without further study, there is no firm evidence that egg yolks are as bad for you as smoking.

Where did the story come from?

The study was carried out by researchers from the Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, and other research institutions in Canada and was funded by the Heart & Stroke Foundation of Ontario.

The study was published in the peer-reviewed medical journal: Atherosclerosis.

While the Mail reports that eating egg yolks is two-thirds as bad for you as smoking when it comes to artery build-up, this cannot be concluded when you consider the limitations of this single piece of research. Also, the headline does not make it clear that the researchers were only looking at people with pre-existing risk factors for heart disease and not the population at large.

What kind of research was this?

The authors report that although high cholesterol contributes to heart disease, there is a general lack of consensus on whether eggs actually raise blood cholesterol and contribute to heart disease.

This study aimed to examine whether egg yolk consumption was related to the fatty (plaque) build-up in the arteries of a consecutive series of adults attending a vascular clinic in Canada.

The design of this study includes several limitations:

• it recruited a small, selective sample of adults
• egg yolk consumption is being estimated through questionnaire responses which may contain inaccuracies
• other factors not studied by the researchers, such as less exercise or a diet higher in other saturated fats, may also contribute towards a build-up of plaque

What did the research involve?

The observational study included 1,231 consecutive patients (average age, 62) referred to a vascular prevention clinic at a hospital in Canada. The total plaque area of their carotid arteries (the main arteries in the neck supplying blood to the head) was measured by ultrasound scan. At the time of referral lifestyle information was also measured by questionnaire. This included smoking history and the frequency of egg yolk consumption. From these responses the researchers calculated:

• pack-years of smoking: the number of packs of cigarettes per day multiplied by the number of years of smoking
• egg-yolk years: the number of egg yolks per week multiplied by the number of years consumed

The researchers specifically say that they did not assess:

• alcohol intake
• exercise taken
• liquorice consumption (high intake of liquorice can increase blood pressure and cause problems in people with heart disease)

What were the basic results?

Overall the researchers found that, as would be expected, the extent of plaque build-up in the carotid arteries increased with age. They also found that both increased smoking and increased egg yolk consumption were associated with more plaque build-up.

Average plaque area in the carotid arteries of patients consuming less than two eggs per week (388 people) was 125mm2 compared to 132mm2 in those consuming three or more eggs per week (603 people). This was a statistically significant difference (not the result of chance).

The association was not affected by adjustment for age.

The researchers did additional analysis adjusting for other cardiovascular risk factors, such as:

• sex
• total blood cholesterol
• blood pressure
• diabetes
• body mass index (BMI)
• smoking

The researchers do not give figures for the build-up in the arteries associated with smoking, but say that the increase in total plaque area with increasing egg consumption followed a similar, linear pattern to that of cigarette smoking.

The highest consumption of eggs (eating more than 200 yolks per year) was said to be equivalent, in terms of plaque build-up, to two thirds of the effect of the highest amount of smoking – the figure quoted by the Mail.

How did the researchers interpret the results?

The researchers say that their findings suggest that regular consumption of egg yolk should be avoided by people at risk of cardiovascular disease. They do acknowledge though, that their theory should be tested in a prospective study that includes more detailed information about diet and other possible confounding factors, such as exercise and waist circumference.

Conclusion

This study found that egg yolk consumption was associated with increased fatty build-up in the arteries of the neck, though this was small when compared to the build-up expected with age. This study has important limitations which mean that it cannot be concluded that egg yolks are as bad for you as smoking:

• Average egg yolk consumption per week and duration was evaluated through a questionnaire response. These are only estimates and may include a considerable degree of inaccuracy. Consumption may vary over time. We also don’t know how these eggs were prepared (boiled, fried in oil, scrambled in butter, etc).
• This wasn’t a trial, and so people are choosing the number of egg yolks they eat. People who ate more egg yolks may differ in other health and lifestyle factors from people who ate less, and this may account for their different artery build-up. For example, as the researchers rightly acknowledge, they did not thoroughly assess other dietary factors, exercise or waist circumference. It is possible that higher egg yolk consumption could be associated with less exercise and higher overall saturated fat intake – both well known risk factors for heart disease. The small changes in fatty build-up in the arteries seen with higher egg yolk consumption could have been accounted for by these other factors.
• None of the participants in this study were reported to be suffering from heart disease and the heart arteries were not examined.
• We do not know how or whether the extent of fatty build-up in the neck arteries was associated with build-up in the heart arteries.
• This is a relatively small, select sample of people attending a vascular clinic in Canada, and further quality studies would be needed to better assess the question.

This study perhaps best supports the notion of all things in moderation. Eggs are a good source of protein in addition to other vitamins and minerals and most experts advise that they can form part of a healthy, balanced diet.

If you have been told you have pre-existing risk factors for heart disease, or other CVDs, your GP will be able to provide more detailed advice about a recommended diet. 

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

Links to the headlines

'Eating egg yolks is as 'bad as smoking' in speeding up coronary heart disease'. Daily Mail, August 15 2012

Links to the science

Spence D, Jenkins DJA, Davignon J. Egg yolk consumption and carotid plaque. Atherosclerosis. Published online July 31 2012

More exercise in your 50s 'cuts heart disease risk'

reposted from: http://www.nhs.uk/news/2012/08august/Pages/Never-too-late.aspx via Netvibes

crabsallover highlights, key points, comments / links.

Tue Aug 14, 2012 10:32 

"Exercise in midlife protects heart," says BBC News, while the Daily Mail tells us that "gardening, walking and DIY in your fifties can cut risk of heart disease".

The news is based on a large study looking at the health of middle-aged people. Researchers found that those who met physical activity recommendations of at least 2.5 hours of moderate to vigorous exercise a week had lower levels of inflammation in their body compared with people who did not get enough exercise.

Reducing levels of inflammation is important as persistent inflammation, even at relatively modest levels, is thought to contribute to the adverse effects of ageing. For example, it is thought to contribute to loss of muscle power and strength, cardiovascular disease or CVD (conditions that affect the heart and blood vessels) and depression.

Interestingly, the results were independent of body fat. This suggests that exercise was still of significant benefit for people with no, or little, previous history of exercise.

The study had some limitations, including the fact that it measured markers of inflammation rather than CVD rates themselves. Nevertheless, this was a well conducted study that reinforces the health benefits of even moderate exercise.

Where did the story come from?

The research was part of the Whitehall II study ... The study was published in the peer-reviewed journal Circulation.

This story has been covered by the BBC, The Daily Telegraph and the Daily Mail. The news coverage was accurate.

The media coverage of the study focused on the fact that the average age of the participants was almost 50. However, although this was the case, the study did not address when in your life exercise is the most beneficial. The Department of Health recommends that all people, whatever their age, take part in regular physical activities.

What kind of research was this?

This was a prospective cohort study that aimed to examine the association between long-term physical activity behaviour and low-grade inflammation over a 10-year follow-up period.

Although a cohort study was the appropriate study type to investigate the association between exercise and inflammatory markers, it cannot prove that exercise directly caused the differences.

A randomised controlled trial (RCT) with a long follow-up would be required to show direct cause and effect (causation). However, such a trial would be unethical to perform as people in a control group who were told not to exercise could damage their health.

What did the research involve?

Participants were part of the Whitehall II population-based cohort, which aimed to investigate social and occupational influences on cardiovascular disease risk. This study used data from 4,289 men and women who were recruited from the British civil service, who were 49 years old on average.

These people answered questions about the frequency, the amount and the intensity of activity they did in a week. This information was collected in 1991-1993 (the study start), 1997-1999 and 2002-2004 (the study end). The participants were analysed separately depending on whether they followed physical activity guidelines of at least 2.5 hours a week of moderate to vigorous physical activity.

Moderate-intensity exercise is defined as working hard enough to raise your heart rate and break a sweat, such as walking fast or pushing a lawn-mower. Vigorous-intensity exercise is defined as any exercise that causes a person to breathe hard and fast and significantly accelerate their heart rate, such as jogging or riding a bike at speed.

During each of the three time periods, the study participants were also clinically examined, had their height, weight, waist and hip circumference and blood pressure measured, and answered health and demographic questions.

A fasting blood sample was also taken, so the levels of two proteins known to be associated with inflammation – C-reactive protein and interleukin-6 – could be measured.

C-reactive protein Normal concentration in healthy human serum is usually lower than 10 mg/L, slightly increasing with aging. Higher levels are found in late pregnant women, mild inflammation and viral infections (10–40 mg/L), active inflammation, bacterial infection (40–200 mg/L), severe bacterial infections and burns (>200 mg/L).[23]

The researchers examined associations between baseline physical activity and long-term physical activity and inflammatory markers, after adjustment for:

• age
• gender
• smoking
• employment grade
• body mass index
• chronic (long-term) illness

What were the basic results?

The researchers found that approximately half of the study’s participants stuck to the recommended 2.5 hours a week of moderate to vigorous physical activity across all three assessments over the 10 years. Fulfilling the physical activity recommendations was associated with lower levels of inflammatory markers at baseline. There was no significant association between physical activity levels at baseline and change in the levels of inflammatory markers over time. This meant that the difference remained stable.

People who fulfilled the physical activity guidelines at all points during follow-up had lower levels of inflammatory markers than those who only fulfilled the guidelines at one point of follow-up, if at all. In addition, people who reported an increase in physical activity of at least 2.5 hours a week during the study had reduced inflammatory markers compared with those whose activity levels remained stable.

The researchers found that these associations were independent of measures of ‘fatness’ such as BMI or waist circumference. This is important because fatness could be used to explain the association seen, as people who adhered to the physical activity guidelines tended to have lower BMI, and fat tissue is a key site for the production of several inflammatory markers.

The fact that the association remained even in people with higher BMIs or waist circumference suggests that exercise can still benefit people who are overweight or obese with no previous history of exercise. As the Mail’s headline says, “it is never too late” to start exercising.

The researchers also found that people with higher levels of inflammatory markers at baseline had reduced physical activity over the follow-up period. This may be because inflammatory processes are thought to be involved in loss of skeletal muscle and functional decline. 

So, while exercising in middle-age can bring important benefits, to achieve the greatest potential benefit from exercise, people should aim to remain physically active throughout their lives.

How did the researchers interpret the results?

The researchers said: “Regular physical activity is associated with lower markers of inflammation over 10 years of follow-up and thus may be important in preventing the pro-inflammatory state seen with aging”.

Conclusion

This study has found that people who did at least 2.5 hours of moderate to vigorous exercise regularly had lower levels of inflammatory markers over 10 years of follow-up. Levels of inflammatory markers gradually increase with age, and they are thought to play a role in the development of cardiovascular disease and other age-related conditions.

This was a prospective cohort study, which used people from a well understood cohort (the Whitehall II cohort, which recruited participants from the civil service). Participants in the study were followed for a long period, and measurement of all the exposures and outcomes of interest were taken repeatedly. However, although a cohort study was the appropriate study type to investigate the association between exercise and inflammatory markers, it cannot prove that exercise directly caused the differences as other unmeasured factors may have contributed. Also, when interpreting the results it is important to consider that the researchers measured inflammatory markers rather than the incidence of cardiovascular disease. Also, the study collected levels of activity using a questionnaire, which means that levels may not have been reported accurately. Finally, most of the people in the active group were men, so this finding may not apply to women.

However, this study adds weight to the case for regular exercise. The news coverage has focused on the fact that the average age of the participants was almost 50 years old, showing that exercise is beneficial at any age. 

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

Links To The Headlines

Exercising in midlife protects heart, says research. BBC News, August 14 2012

Exercising later in life can ward off heart problems. The Daily Telegraph, August 14 2012

It's never too late to exercise: Major new British study proves that starting gardening, walking and DIY in your fifties can cut risk of heart disease. Daily Mail, August 14 2012

Links To Science

Hamer M, Sabia S, Batty GD, et al. Physical Activity and Inflammatory Markers Over 10 Years: Follow-Up in Men and Women from the Whitehall II Cohort Study. Circulation. Published online August 13 2012

http://circ.ahajournals.org/content/early/2012/06/28/CIRCULATIONAHA.112.103879.full.pdf+html - full free reference.

Can exercise reduce chances of dementia?

reposted from: http://www.nhs.uk/news/2012/04april/Pages/exercise-resistance-training-dementia.aspx

The truth about exercise with Michael Mosley

reposted from: http://www.bbc.co.uk/iplayer/episode/b01cywtq/Horizon_20112012_The_Truth_About_Exercise
and http://www.bbc.co.uk/news/health-17177251

crabsallover highlights, key points, comments / links.

• exercise is not going to reduce weight if you eat more! (9 mins)
• levels of fat in blood are reduced if walk because exercise turns on lipoprotein lipase genes which metabolises fat in muscles, rather than dumping fat to gut. Thus fat in blood fell by 33% as a result of the 90 minute walk the night before. (10-17 mins)
• 150 mins per week moderate exercise or 75 mins per week vigorous exercise is government guideline
• Nottingham Uni, Prof Jammie Timmons (18 mins), 4 year study - big variation in response to exercise - 20% don't respond much to exercise, 15%  respond a lot. This response has been traced to 11 genes (reference) - can predict how an individual will respond using a gene test.
• 23 mins: a few minutes intensive exercise a week, High Intensity Training (HIT) protocol, x3 times a week x 20s x3 equivalent to a couple of hours exercise. Glycogen is broken down, improves insulin sensitivity. Activate 70% muscles cf jogging 30%. After 6 weeks get improvement.
• insulin sensitivity, if defective cannot get rid of sugar - become diabetic
• HIT Benefits
• 23% improvement: Glycogen is broken down, improves insulin sensitivity - after 1 month
• VO2 max - oxygen - non-responder predicted by genetic tests
• Reference and another reference via BBC.
• James Levine, Mayo clinic (32 - 44 mins)
• NEAT = Non Exercise Activity Thermogenesis - calories you burn in everyday living
• walking at 1.3mph doubles metabolic rate, at 2.2 mph triples metabolic rate
• standing - 10% increase metabolic rate
• 80% people don't do regular exercise
• there should never be an hour that you are just sitting down. The chair is killing millions. It's not enough to go to the gym. Got to be active all the day.

Exercise 'protects brain from ageing'

reposted from: http://www.nhs.uk/news/2010/12December/Pages/exercise-protects-against-mental-decline.aspx
crabsallover highlights in red

“Regular exercise may be the best way to keep ageing brains sharp,” says The Daily Telegraph. The newspaper has reported that a new review of research has shown that even low to moderate exercise prevents the milder forms of cognitive decline in older age.

The research pooled the results of 15 studies and found that low to moderate exercise, such as playing a round of golf once a week or tennis twice a week, was linked to a 35% reduction in the risk of cognitive decline. The researchers think that this could be due to physical activity increasing blood flow to the brain.

This review of observational studies was well conducted and reported. It includes an analysis of over 30,000 people and it seems likely that the researchers have sourced the most important studies on this topic. Although these were not randomised studies, the consistency and strength of the evidence appears to provide the best current estimate of activity’s ability to prevent normal, age-related brain changes such as the decline of memory.

Where did the story come from?

The study was carried out by researchers from the University of Florence and other institutions in Italy. No external sources of funding are noted. The study was published in the Journal of Internal Medicine.

The Daily Telegraph summarised this meta-analysis accurately, placing the research in context and reporting some of the researchers’ estimates of the size of exercise’s effect.

What kind of research was this?

This was a meta-analysis that aimed to pool the results of prospective cohort studies on physical activity and cognitive decline. The researchers pooled the data from 15 studies that between them included over 30,000 non-demented subjects who had been followed for a period of one to 12 years. Among this population, over 3,000 new cases of cognitive decline occurred.

The meta-analysis showed that individuals who were physically active at the start of the study (baseline) had a significantly reduced risk of developing cognitive decline during follow-up.

The researchers explain that it is already known that physical activity has positive effects on a wide range of health measures, reducing the risk of heart disease and stroke, diabetes, obesity, hypertension and some cancers.

Attention, memory and concentration (known as cognitive functions) typically decline with age,  becoming slower and less efficient, much as physical functions such as walking and balance do. The authors argue that these cognitive changes can become noticable and can cause mild disability, even if a state of dementia is not reached.

The authors have described using a comprehensive procedure for finding relevant research and, importantly, only included studies if patients recruited had received a clinical evaluation at the start of the study and did not suffer from dementia. As participants were followed up over time, the new evidence provided by this meta-analysis supports the role of exercise programmes in preventative medicine, as maintaining activity levels into later life seems to slow the onset of memory loss associated with normal ageing.

What did the research involve?

In this study the researchers searched a number of computer databases including Medline, Embase, Google Scholar, Web of Science and the Cochrane Library. They retrieved and assessed articles published up until January 2010, plus studies cited within these articles. Studies were included only if the association between physical activity and cognitive decline in subjects without dementia was analysed prospectively (ie were prospective cohort studies).

The researchers used and reported best practice systematic review methods, including assessment of studies by two separate people and appraisal and statistical analysis for any publication bias among the studies they found. They excluded studies of other design, such as case control or cross-sectionalstudies, plus any that included people with dementia at the start.

They adjusted for a range of other factors that could have influenced the result such as age, education, smoking, alcohol, use of NSAID medication, self-rated health and some chronic conditions. They also appropriately used a random effects model, a type of statistical analysis that in part takes into account the statistical differences in studies included.

What were the basic results?

Fifteen publications of 12 prospective cohorts were included in the final analysis, from a total of 58 papers identified by the researchers. These studies included 33, 816 people without dementia who were followed for up to12 years. A total of 3,210 patients (about 9.5%) showed cognitive decline during the follow-up.

The analysis of all the studies showed that subjects who performed a high level of physical activity were significantly more protected (by 38%) against cognitive decline (memory loss etc) during the follow-up, compared to people who reported being sedentary (hazard ratio [HR]) 0.62, 95% confidence interval [CI] 0.54 to 0.70).

The researchers also looked at the effect of exercise of a low to moderate level, and found that this too protected against cognitive impairment compared to being sedentary. It provided a significant protection of 35% (HR 0.65, 95% CI 0.57 to 0.75).

They tested to see if the studies were similar enough to allow them to pool the results in a valid way and found that they could. Technically there was no significant heterogeneity (variation) among the studies (I2 = 17%; P = 0.26) and no publication bias.

How did the researchers interpret the results?

The researchers claim that this is the first meta-analysis to evaluate the role of physical activity on cognitive decline among people without dementia. The results, they say, suggest a “significant and consistent protection for all levels of physical activity against the occurrence of cognitive decline”.

Conclusion

These results have highlighted the important role that even low levels of physical activity can play in protecting people from the decline in mental function that can routinely occur in healthy people as they age.

The importance of the study lies in its application to an ageing population and the study has both strengths and some weaknesses:

• One clear strength is the size of the study, with a large number of people for whom the researchers had data. This increases confidence in the result.
• Publication bias was not evident in the studies analysed, which supports the validity of this meta-analysis. Publication bias is the  tendency for those involved in studies to handle the reporting of positive results (those that show a significant finding) differently from results that are negative or inconclusive ones.
• A limitation to the study was that the methods used to measure cognitive decline and physical activity varied across the included studies. The MMSE test (a recognised cognition test) was the most frequently used tool for diagnosing cognitive decline, but other tests were used in some studies. Though an unavoidable weakness of this study, the researchers tested for the effect and concluded it was not a significant problem.
• This study did not find a clear ‘dose dependent’ effect, ie an association in which increasing levels of activity resulted in increasing levels of protection.
• The protective effect appears stronger for women than for men, and it is not clear why.
• The studies included in the analysis may have had different definitions as to what are moderate and what are high levels of physical activity. Further clarification may be needed to see how much physical activity elderly people should aim to do.

Randomised trials, though possible in the area of physical activity, would need to be large and follow people for a long time to find these sorts of results. The practical constraints of performing such a study suggest that for the time being this well-conducted meta-analysis provides probably the best evidence that this important link exists.

The authors now call for further studies to determine the best “type, frequency and intensity of exercise” or physical activity that maintains memory into old age.

The study is reliable, well conducted and reported. Though the findings may be unsurprising, as some individual studies had already shown significant results, the summary of a large body of evidence adds weight to the science behind the established link between low levels of physical activity and cognitive decline.

Links to the headlines

Exercise keeps ageing brain sharp. The Daily Telegraph, December 23 2010 [Print only]

Staying fit ‘sharpens your brain’. Daily Express, December 23 2010 [Print only]

Links to the science

Sofi F, Valecchi D, Bacci D, et al. Physical activity and risk of cognitive decline: a meta-analysis of prospective studies. Journal of Internal Medicine 269; 107–117

Further reading

Forbes D, Forbes S, Morgan DG, Markle-Reid M, Wood J, Culum I.Physical activity programs for persons with dementia. Cochrane Database of Systematic Reviews 2008, Issue 3