In the study, a high-fat diet, which creates diabetes-like changes to blood sugar metabolism, was administered to both the control group and the test mice.  Typically, engaging in exercise has the ability to prevent metabolic blood sugar abnormalities, even in the presence of a high-fat diet.  The University of Texas Southwest Medical Centre researchers found that the mice that were unable to respond to exercise by increasing autophagy did not experience the benefits exercise provides on blood sugar metabolism.

The findings of the research team suggest not only that exercise is able to reduce or reverse changes in blood sugar due to a high fat diet among those with normal autophagy function, but also that autophagy is a key process that protects against diabetes by improving glucose metabolism.

In additition, the study raises the prospect that activating the autophagy process could play a key role in other exercise benefits, like reducing cancer risk, according to the senior author who leads the Centre for Autophagy Research.

Sources: Zeenews.com, 21 January 2012; He et al., Nature 481: 511-15, 18 January 2012.

Researchers recorded changes in BMI and physical fitness over six years among these men, 90 per cent of whom were overweight or of normal weight to begin with, but not obese.  Appropriate measures were taken to ensure that intervening variables, such as diabetes status, family history of cardiac disease, and lifestyle factors were accounted for. After more than 11 years of follow-up study they drew conclusions around the relative risks of mortality for men who had lost, gained or maintained fitness during these six years.

Though some individuals are physically active, they nonetheless do not lose weight or change BMI. The results of this study gives help to these people, says Dr Duck-chul Lee, an a physical activity epidemiologist in the Arnold School’s Department of Exercise Science and one of the authors of the study.

Results suggest that a reduction in fitness levels is associated with a higher risk of death from all causes and that for each unit of increased fitness a 19 per cent lower risk of heart disease and stroke-related deaths and a 15 per cent lower risk of death from any cause. As this study focused on normal or overweight men, it remains unclear whether these findings would apply to women or obese men.

How much physical activity is enough? Read more here >>

Sources: ‘Physical activity trumps body weight in reducing death risks’, University of South Carolina press release, 5 December 2011; ‘Long-term effects of changes in cardiorespiratory fitness and body mass index on all-cause and cardiovascular disease mortality in men: The Aerobics Center Longitudinal Study’, Circulation: Journal of the American Heart Association, December 2011;  WHO factsheet on physical activity, click here >>

There are now some signs that environmentalists and health professionals are beginning to take note of the synergies available in tackling climate change and human health. The Climate and Health Council (here >>) is a network of health professionals interested in this area (around 5,000 of whom, from over 70 countries, have signed a Pledge to protect health and call for a framework to control carbon emissions). The first ever Global Climate and Health Summit Summit (co-organised by the World Federation of Public Health Associations, the Climate and Health Council, Health Care Without Harm and the Nelson R. Mandela School of Medicine at the University of KwaZulu Natal, in partnership with the World Health Organization, the World Medical Association and the International Council of Nurses, among others) is being held on 4 December to coincide with COP17 (more information will be available here >>).

For tweets on health from COP17, follow Climate Health Connect on Twitter (here >>).

The voice of health professionals has been largely silent in the discussions to date, despite the substantial role that the sector can play in reducing carbon emissions – not only by saving money by reducing the environmental footprint of health facilities, but by promoting the clear win–wins for human health when working to mitigate climate change, with many of these potential gains relating to the major risk factors for NCDs:

• Transport is a major contributor to CO₂ emissions. Reducing the number of miles driven – substituting walking and cycling – is an obvious way in which human health could benefit from what appears to be a primarily environmental intervention. This will reduce air pollution (which contributes to the risk of CVD, COPD and lung cancer) and traffic accidents – each of which cause over 1 million deaths a year: mortality in cities with high levels of pollution exceeds that of relatively cleaner cities by 15–20%. And replacing car use with walking and cycling will also work to reduce levels of overweight and obesity.
• Diet also impacts both on our health and the environment. Meat and dairy production currently accounts for about a fifth of greenhouse gas emissions worldwide – and consumption may double by 2050 if current trends continue. Diets that are high in red meat are also unhealthy – consumption of red meat has been linked to many cancers (including bowel and breast cancer), and meat is high in saturated fats, which can contribute to other NCDs such as heart disease.
• Indoor air pollution, largely caused by open fires or traditional stoves, is not only an environmental hazard: it is responsible for around 2 million deaths annually, mostly in developing countries. It increases the risk of acute lower respiratory infections among young children, and is a major risk factor for COPD and lung cancer in adults, especially women. Finding less environmentally damaging options could also save millions of lives.

COP17 represents a huge opportunity that must not be squandered. ‘What is good for the planet is good for health’ is a message that has the potential to be a powerful political lever for policy-makers, bringing home the real impact that climate change will have on many billions of people.

The increased demands we face on our ‘neurocognitive resources as well as their overuse and/or impairment may facilitate impulses to over-eat, contributing to weight gain and obesity’. However, the study shows that the drive to overeat can be counteracted by taking exercise – this enhances neurocognitive resources for executive functions and goal-oriented behaviour – helping both in the short term (increased sensitivity to physiological signs of fullness) and long term (behaviour change).

As one of the authors, Miguel Alonso Alonso, from Harvard, commented: ‘in time, exercise produces a potentiating effect of executive functions including the ability for inhibitory control, which can help us to resist the many temptations that we are faced with every day in a society where food, especially hypercaloric food, is more and more omnipresent’.

Sources: Stone Hearth News, 23 November 2011; R.J. Joseph et al., ‘The neurocognitive connection between physical activity and eating behaviour’, Obesity Reviews 12(10): 800–12.

According to recent research conducted in Taiwan and published in the Lancet, the minimum exercise required to have an impact on health is 15 minutes daily.  This prospective cohort study, conducted between 1996 and 2008, evaluated hazard ratios of mortality for participating men and women based on self-administered questionnaires.  The 416,000 people who participated in the study were grouped based on exercise levels, which ranged from inactive to very high.

The findings of this study also show that each additional increment of 15 minutes of physical activity beyond the 15-minute minimum yields an additional statistically significant reduction in mortality by all causes across age, gender, and includes individuals with cardiovascular disease risk. Individuals who were inactive had a significant increase in all-cause mortality.

Thirty minutes of exercise five times a week is the usual recommendation for good health. During the summer, the UK government revised its published physical activity guidelines, acknowledging that adults can take a more flexible approach to physical activity, advising that adults can take benefit from being active in just 10 minutes a session, and that people may want to be active each day to achieve at least 150 minutes of physical activity weekly. Some may want to be active for half an hour five times each week; others may prefer several bursts of high-exertion activity.  These recommendations for weekly physical activity are intended to be more flexible to accommodate today’s often busy lives.

For more information on the benefits of physical activity for health, download C3’s report The Benefits of Physical Activity for Health and Well-being here >>.

Sources: Wen et al., ‘Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study’, The Lancet, volume 37, 1 October 2011; Yahoo Sports, 14 November 2011.

Maria Glymour, of Harvard School of Public Health, noted that the analysis in the latest study ‘seems very convincing’, but points out that it is not understood whether depression causes the increased risk, or if the two conditions share underlying causes. She told Reuters Health, ‘we know that depression affects the behaviour that influences your stroke risk, such as diet, physical activity, adherence to health advice. Those things take a certain amount of energy, and being depressed might affect your ability to do them.’

Sources: Reuters Health, 21 September and 2 November 2011; An Pan et al., ‘Depression and Risk of Stroke Morbidity and mortality: a meta-analysis and systematic review’, JAMA ; and Jia-Yi Dong et al., ‘Depression and risk of stroke: a meta-analysis of prospective studies’, Stroke, 20 October 2011.

In particular, obesity unduly stresses the endoplasmic reticulum, the physiologic structure where proteins in a cell are collected and sent off to do various duties for the cells.  This type of stress harms the body’s ability to manage appropriate glucose levels, which is in large part responsible for the link between obesity and diabetes.

Two proteins involved in regulating blood sugar levels are actually activated via inflammation pathways and research conducted by the Children’s Hospital, Boston, shows that activating this inflammation process in mice may actually provide a positive influence on blood sugar levels.

The Children’s Hospital research identifies another protein reaction developed from the Inflammation process which is beneficial in maintaining glucose levels – and that by stimulating this key protein in laboratory mice glucose tolerance can be improved. Further research, of course, is needed to determine whether this will be the case for humans.

Sources: Nature Medicine, 4 September 2011 (online), Science Daily, 5 September 2011.

A recent correlative descriptive study published in the International Journal of Nursing Practice and widely reported in the media, describes the crucial link between the belief nurses have in the overall benefit of physical activity and their likelihood of recommending and teaching exercise as a health behaviour.  The purpose of the study was to investigate key relationships between individual exercise behaviours, beliefs about exercise, and patient recommendations.

Using Pender’s Theory of Health Promotion, which defines health promotion as a multi-dimensional effort to improve patient well-being, this study looks at beliefs, behaviours and recommendations, and affirms previous research showing that nurses who believe in the benefits of exercise and personally model positive exercise behaviours are more likely to share and teach positive behaviours around exercise.  The results of this small study of 112 nurses in a 1000/bed hospital in New York, compares to previous research in this area.  The majority of practicing registered nurses in the US are overweight or obese, as are almost half of the registered nurses at this hospital.  The study found that both nurses and patients benefit from support and encouragement in developing healthy behaviours and that nurses who confront personal challenges with overweight help patients by sharing their own struggles with weight-related issues.

Nurses can be vital role models for positive patient behaviour, but also require support and positive reinforcement.

Sources: International Journal of Nursing Practice, 2011, and Science Daily, 4 September 2011.

People in the ‘low’ activity group (exercising an average of 92 minutes a week – 15 minutes a day) were found to have a 14 per cent reduced risk of all-cause mortality, and a three-year longer life expectancy. Beyond this, every additional 15 minutes daily further reduced all-cause mortality by 4 per cent, and all-cancer mortality by 1 per cent.  These benefits applied to both sexes and across all age groups, and included those with CVD risks.

Prof Stuart Biddle, an expert in exercise psychologist at Loughborough University, commented that ‘You can get good gains with relatively small amounts of physical activity. More is always better, but less is a good place to start.’

Sources: BBC news online, 16 August 2011 and The Lancet (online), 16 August 2011 (C.P Wen et al., ‘Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study’)

The benefits can be striking: research has indicated that this amount of exercise can reduce the risk of breast cancer recurring by 40 per cent, and reduce the risk of dying from prostate cancer by up to 30 per cent. Among bowel cancer patients, taking more exercise – around six hours a week – can reduce the risk of dying by around 50 per cent. Taking exercise will also help to overcome tiredness and weight gain, and protect against cardiovascular disease and osteoporosis.

Jane Maher, chief medical officer of Macmillan Cancer Support and a clinical oncologist noted: ‘The advice that I would have previously given to one of my patients would have been to “take it easy”. This has now changed significantly because of the recognition that if physical exercise were a drug, it would be hitting the headlines.’

C3 Collaborating for Health has produced a report on the benefits of physical activity on health, which can be downloaded here >>

Source: BBC News online, 8 August 2011.