Team McCallum

R&D for Lifetime of Life

Walking v diabetes+.

Dr Terry Dwyer and colleagues have found that walking cuts the risk of diabetes in a study of 600 adults in Tasmania. While the team focussed on diabetes, the results suggest a protective effect against metabolic syndrome and cardiovascular disease.

Roughly 600 adults aged around 50 in 2000 were tracked for 5 years.  At the start, most were overweight or obese and as a whole, the group gained weight over the period.

The volunteers were fitted with pedometers for 2 days in 2000. One finding was that those with higher daily step counts at this start time ended with a better body mass index (BMI), better waist to hip ratio and better insulin sensitivity, compared to those less active.

After 5 years, the group wore pedometers for another 2 days. As a whole, the group gained weight and became less active.  However, one third stayed active or increased their steps in the period, and again these were the ones with better measures on BMI, waist-hip ratio and insulin sensitivity.

The following figures are for those walking 10,000 steps, which is about 5 miles or 8km.

For a person of average height, weight dropped was just under 3kg, or about 6lbs. This corresponds to a BMI reduction of 0.83kg/metre squared. Insulin sensitivity increased by about 12%, with men doing slightly better than women.

These results are all ‘dose-dependent’. In other words, walking less still resulted in some improvements.

When the researchers factored in BMI, the differences between those active and those not disappeared, so the team attributed the improvement to a cut in body fat.

The researchers were looking at diabetes, and the improvement in insulin sensitivity would result in a considerably reduced risk of the disease.

The figures also strongly suggest there would be an improvement in other diseases linked to BMI and larger waists, including high blood pressure, metabolic syndrome, cardiovascular disease and more.

The impact on the waist is interesting, since fat stored around the waist is linked to adiposopathy (sick fat), and this study suggests that walking is a way to burn ‘sick’ fat preferentially to ‘healthy’ fat, reducing the waist to hip ratio.

Advertisements

January 17, 2011 Posted by | Accelerometer, Activity, Adiposopathy - sick fat, Aging, BMI - body mass index, CVD - cardiovascular disease, Diabetes, Exercise, High blood pressure, Metabolic syndrome, Success, Waist circumference, Walking, Weight management | Leave a comment

Yoga v walking for mood?

Dr Chris C Streeter of Boston University School of Medicine compared the effects of walking to yoga and the impact on mood in healthy people.

Previous research had shown that yoga increases a neurotransmitter, called GABA, in the brain. Increasing GABA is linked to less anxiety and depression, and cuts PTSD (post-traumatic stress disorder). Increasing levels of GABA is one approach used in medicines to treat these conditions.

The current study was designed to see if yoga’s known beneficial effects on mood were due to GABA effects, or simply due to exercising (which also improves mood, depression etc). So Dr Streeter tried to match the exercise content of walking with the exercise content of yoga, to see which would win.

Brain scans were used to check on activity in the thalamus. This is an area of the brain involved in mood, and it gets more active at higher levels of GABA.

This is where things went a bit different to what the research team thought would happen.

The yoga group showed a bigger improvement in mood than the walking group. And the yoga people appeared to show more activity in the thalamus, so more GABA. So far so good.

However, the number of people completing the study was small, and the improvement in GABA was not statistically significant. The groups also had a couple of key differences – the yoga group drank more alcohol, while the walking group exercised more when out of the yoga/walking comparison. Perhaps the walkers improved less because they were already getting lots of benefit from exercise.

Or could it be that the yoga group got certified instructors in lyengar yoga, while the walking group got to walk around the inside of gym for an hour per session?

The jury is out, but the research did turn up one key finding.

This study lasted 12 weeks and involved people new to yoga, and it produced about half the increase in GABA that previous studies with experienced practitioners had reported. So if you want to get the full mood benefits of yoga, you’re going to have to stick with it for a fair while.

November 13, 2010 Posted by | Activity, Anxiety, Brain, Depression, Exercise, PTSD, Success, Walking | Leave a comment

Beating mental decline?

A study of 300 elderly adults in the US has found that walking an average of a mile a day is linked to a higher amount of grey matter in the brain and a lower risk of mild cognitive impairment and dementia.

Around 1990, Dr Kirk I Erickson recruited elderly people, average age 78, and asked how much walking they did. This was the only activity queried. The participants were also screened to ensure they were free from mental decline.

9 years later, those still in the study had a brain scan to look at several brain parameters.

4 years later the participants were assessed by professionals to check for mild cognitive impairment and dementia, possible precursors to Alzheimer’s.

The results showed that walking a mile a day was associated with higher grey brain matter at the 9 year point. There was no significant difference in other brain parameters.

Simplifying greatly, grey matter is where the brain ‘calculates’, while white matter is the communication network connecting the grey matter areas.

Walking more than a mile per day, going as high as four times this, did not show any more grey matter than the one mile walk.

Those with more grey matter were found to half the risk of cognitive impairment compared to those without.

The study simply links walking, grey matter and cognitive impairment, but does not prove cause and effect. For example, a recent study in mice found those with cognitive impairment explored less than those without. However,  other studies have also found activity is linked to a reduced risk of cognitive impairment and Alzheimer’s.

October 15, 2010 Posted by | Activity, Aging, Alzheimer's, Brain, Dementia, Exercise, Health, Kirk I Erickson, Success, Walking | Leave a comment

Neighbourhood choice test.

Pretend that you are going to move soon. Rate the desirability of the following two characteristics for your new neighbourhood, from not important at all to very important –
– ease of walkability
– close to outdoor recreation facilities.

Dr Tanya R Berry examined the relationship between a number of reasons for choosing a neighbourhood and weight change in nearly 1,800 Canadians over a period of 6 years, and found some odd results.

Weight and body mass index (BMI) tend to increase with age, so the question was who would gain the most or gain the least.

A number of desires relating to neighbourhood choice made no difference to weight gain, but walkability and close to outdoor recreation did.

Those who rated walkability highly gained less than those who did not care about it.

But those who rated nearness to outdoor recreation highly gained more than those who did not care about this, a finding that the researchers could not explain in this study.

September 25, 2010 Posted by | Activity, BMI - body mass index, Success, Tanya R Berry, Walking, Weight management | Leave a comment

The dog diet?

Dr Christopher Owen found that 9 and 10 year-old children who owned a dog were more active and less sedentary than those who didn’t.

Over 2,000 children in 3 major cities in the UK were fitted with accelerometers to measure their activity levels over a period of a week.

Those with a dog were found to be around 4% more active than those without, which in the children’s case equated to about 360 more steps per day (plus increases at all activity levels and a decrease in down-time).

Although the study didn’t test whether getting a dog made kids more active or more active kids got a dog, this issue has been tested in adults. In the case of adults, getting a dog led to increases of activity.

And the increase in activity for adults is much larger, around 25%, equating to an extra 1,700 steps per day for walkies.

The difference in extra steps of adults and 10 year-old suggests the kids extra activity comes from playing with the dog, rather than going walkies with it.

Whether 10 year-old or adult, think thin, think active, get a dog!

September 22, 2010 Posted by | Activity, Child Health, Christopher Owen, Health, Success, Walking, Weight management | Leave a comment

Euro teens less active at weekends.

A study of 3,300 teenagers in 10 cities across Europe has found that they are less active at weekends, with more time spent on sedentary activities including TV, games consoles and home computers.

According to Juan P Rey-López of the University of Zaragoza “During the week, one-third of teenagers said they watched more than two hours of television per day. At weekends, this figure exceeds 60%”.

While the latest annual survey of health habits among the young population of the community of Madrid found 20% of boys and 10% of girls aged 15 to 16 are overweight or obese. In girls, this figure has almost doubled since the survey started 15 years ago.

Over this period the eating pattern of the teens has not improved, but it has not worsened either, so experts point to an increasingly inactive lifestyle as the reason.

El Pais quoted Clotilde Vázquez, head of clinical nutrition at the Ramon y Cajal hospital, as saying “We must focus on the promotion of daily physical activity. Not sport, but to move, walk or take a bike. Do not get carried from one place to another.”

September 19, 2010 Posted by | Activity, Diet, Exercise, Obesity, Success, Television, Walking, Weight management | Leave a comment

Walking v stress & heart disease.

A study of exercise v stress in adolescents has found that walking cuts the impact of stress directly, and so may cut the risk of later heart disease.

Dr James Roemmich tested 40 girls and boys aged 10-14. Half were given a simulated ride to school. Half took a 1 mile simulated walk, using a treadmill.

After a further 20 minutes, both groups took a standard stress test.

Compared to active commuters, passive commuters reported twice as much stress, the increase in their systolic blood pressure was 3 times larger, and their heartbeat increased by 11 beats per minute, nearly 4 times that of the walkers.

The team does not know how long the protective effect lasts.

Roemmich said until this was known, several activity breaks during the day would seem to be best to protect against stress.

August 14, 2010 Posted by | Activity, Child Health, CVD - cardiovascular disease, Exercise, Health, James Roemmich, Stress, Success, Walking | Leave a comment

BMI and convenience stores.

Prof Samina Raja and team published an exploratory study on women’s body mass index (BMI) and the neighbourhood in Erie County, New York.

BMI was higher the greater the number of restaurants within a 5 minute walk from home.

BMI was lower where there were more supermarkets and grocery stores (full range) than convenience stores (limited range).

This preliminary study did not test whether the women used the convenience stores, nor whether the restaurants were fast food or slow food.

The attempt here was simply to explain the paradox of high BMI rates among women living in highly walkable inner city neighbourhoods.

July 4, 2010 Posted by | BMI - body mass index, Diet, Samina Raja, Success, Walking, Weight management | Leave a comment

Skinny steps, healthy steps.

Dr Peter T  Katzmarzyk fitted an accelerometer to over 1400 people to record the number of steps walked per day.  500 had metabolic syndrome (abdominal fat, high triglycerides, low good cholesterol, high blood pressure, high fasting glucose level) and 900 didn’t.

The people were split into 3 groups on steps walked per day – low (under 5,000), medium, and high (10,000 or more).

Compared to the low group, the odds of having metabolic syndrome dropped 40% in the medium group and 72% in the high group.

Each additional 1,000 steps/day led to an 8%-13% reduction in the odds of high waist circumference, low good cholesterol and high triglycerides. The benefits were somewhat higher in women than in men.

May 8, 2010 Posted by | Accelerometer, Activity, Cholesterol, Exercise, Gender, Health, High blood pressure, Metabolic syndrome, Peter T Katzmarzyk, Success, Walking | Leave a comment

Women walkers cut stroke risk.

A 12 year study of 40,000 US women aged 45+ found that those who walked as a leisure activity cut their risk of stroke significantly.

The study ignored house and work activity.

The research looked at vigorous activities such as sports, running, cycling and swimming, but found no link. The study authors suggest this may be due to insufficient number of women carrying out these activities.

Compared to those who didn’t walk, women who walked briskly (3 mph or more) and those who walked for 2 hours or more per week showed big improvements.

Women who walked briskly cut their total risk by 37%. Those in the 2 hours per week category cut total risk by 30%.

For hemorrhagic stroke (bleeding) the cuts were 68% and 57% respectively. For ischemic stroke (clots), the cuts were 25% and 21% respectively.

The study was reported by Dr I-Min Lee and others in the journal Stroke.

In previous studies in males, the relation between walking and stroke risk has been inconsistent.

April 8, 2010 Posted by | Activity, Exercise, Health, I-Min Lee, Stroke, Success, Walking | Leave a comment