Air pollution cancels positive health effects of exercise in older adults

December 05, 2017

DURHAM, N.C. -- Exposure to air pollution on city streets is enough to counter the beneficial health effects of exercise in adults over 60, according to a new study led by scientists at Imperial College London and Duke University.

The findings, published Dec. 5 in The Lancet, show that short-term exposure to traffic exhaust on a busy street can cancel out the positive effects a two-hour stroll would otherwise have on older adults' heart and lungs.

This is the first study to document these negative effects on healthy people as well as those with pre-existing cardiorespiratory conditions such as chronic obstructive pulmonary disease (COPD) or coronary heart disease.

"This adds to the growing body of evidence showing the negative cardiovascular and respiratory impacts of even a short, two-hour exposure to motor traffic pollution," said Junfeng "Jim" Zhang, professor of global and environmental health at Duke. "It highlights the need for stricter air quality limits and better traffic-control measures in our cities."

"Combined with evidence from other recent studies, our findings underscore that we can't really tolerate the levels of air pollution that we currently find on our busy streets," said Fan Chung, professor of respiratory medicine and head of experimental studies medicine at the National Heart & Lung Institute at Imperial College.

Because the research also showed that volunteers who walked for two hours in a large city park -- away from direct exposure to street-side traffic fumes -- experienced significant improvements in lung and vascular functions, "we call for greater access to urban green spaces for people to exercise," Zhang added.

To conduct the study, the researchers recruited 119 volunteers over the age of 60 who were either healthy, had stable COPD, or stable ischemic heart disease. Volunteers walked for two hours midday at one of two London locations: in a relatively quiet part of Hyde Park or along a busy section of Oxford Street, where pollution -- including black carbon, nitrogen dioxide and fine particulate matter from diesel exhaust fumes -- regularly exceeds air quality limits set by the World Health Organization. Physical measurements taken before and after the walks revealed the effects activity had on each volunteer's cardiopulmonary health, including lung capacity, blood pressure, blood flow and arterial stiffness.

Following a stroll in Hyde Park, volunteers' lung capacity improved significantly within the first hour and this improvement lasted for more than 24 hours in many cases. By comparison, a walk along Oxford Street led to a smaller increase during the first hours and no increase later.

Walking in Hyde Park reduced arterial stiffness by more than 24 percent in healthy and COPD volunteers and more than 19 percent in heart disease patients. Walks along Oxford Street yielded much smaller gains. Healthy volunteers experienced a maximum reduction in arterial stiffness of just 4.6 percent; COPD patients saw a 16 percent reduction; and those with heart disease saw an 8.6 percent reduction.

The researchers noted that stress could account for some of the physiological differences seen between the two settings, with the increased noise and activity of Oxford Street having an effect. They also noted that patients with heart disease who took medication to improve their cardiovascular health experienced less severe effects following exposure to the pollution. The medication had a stabilizing effect.

"For many people, such as the elderly or those with chronic disease, the only exercise they very often can do is to walk," Chung said. "Our study suggests that we might advise these people to walk in green spaces, away from built-up areas and pollution from traffic. But for those living in inner cities, this may be difficult to do, and there may be a cost associated with it as they have to travel further away from where they live or work."

"We need to reduce pollution so that everyone can enjoy the benefits of physical activity in any urban environment," he said.

Chung and Zhang conducted the study with colleagues at the MRC-PHE Centre for Environment and Health at Imperial College London; the NIHR Biomedical Research Unit, Royal Brompton & Harefield National Health Service Trust; Peking University; Duke Kunshan University; the MRC-PHE Centre for Environment and Health at King's College London; and Rutgers, the State University of New Jersey. Funding came from the British Heart Foundation.

Zhang holds faculty appointments at Duke's Nicholas School of the Environment and the Duke Global Health Institute, as well as Duke Kunshan University in China. Co-lead author Jicheng Gong was a postdoctoral fellow of Zhang's at Duke when the study was conducted.
-end-
CITATION: "Cardio-pulmonary Responses to Walking on a Traffic-Polluted Roadside in 'Over-60's' Healthy, Pulmonary and Cardiac Participants," Rudy Sinharay, Jicheng Gong, Benjamin Barratt, Pamela Ohman-Strickland, Sabine Ernst, Frank Kelly, Junfeng (Jim) Zhang, Peter Collins, Paul Cullinan and Kian Fan Chung; The Lancet, Dec. 5, 2017. DOI: http://dx.doi.org/10.1016/ S0140-6736(17)32643-0.

Duke University

Related Heart Disease Articles from Brightsurf:

Cellular pathway of genetic heart disease similar to neurodegenerative disease
Research on a genetic heart disease has uncovered a new and unexpected mechanism for heart failure.

Mechanism linking gum disease to heart disease, other inflammatory conditions discovered
The link between periodontal (gum) disease and other inflammatory conditions such as heart disease and diabetes has long been established, but the mechanism behind that association has, until now, remained a mystery.

New 'atlas' of human heart cells first step toward precision treatments for heart disease
Scientists have for the first time documented all of the different cell types and genes expressed in the healthy human heart, in research published in the journal Nature.

With a heavy heart: How men and women develop heart disease differently
A new study by researchers from McGill University has uncovered that minerals causing aortic heart valve blockage in men and women are different, a discovery that could change how heart disease is diagnosed and treated.

Heart-healthy diets are naturally low in dietary cholesterol and can help to reduce the risk of heart disease and stroke
Eating a heart-healthy dietary pattern rich in vegetables, fruits, whole grains, low-fat dairy products, poultry, fish, legumes, vegetable oils and nuts, which is also limits salt, red and processed meats, refined-carbohydrates and added sugars, is relatively low in dietary cholesterol and supports healthy levels of artery-clogging LDL cholesterol.

Pacemakers can improve heart function in patients with chemotherapy-induced heart disease
Research has shown that treating chemotherapy-induced cardiomyopathy with commercially available cardiac resynchronization therapy (CRT) delivered through a surgically implanted defibrillator or pacemaker can significantly improve patient outcomes.

Arsenic in drinking water may change heart structure raising risk of heart disease
Drinking water that is contaminated with arsenic may lead to thickening of the heart's main pumping chamber in young adults, according to a new study by researchers at Columbia University Mailman School of Public Health.

New health calculator can help predict heart disease risk, estimate heart age
A new online health calculator can help people determine their risk of heart disease, as well as their heart age, accounting for sociodemographic factors such as ethnicity, sense of belonging and education, as well as health status and lifestyle behaviors.

Wide variation in rate of death between VA hospitals for patients with heart disease, heart failure
Death rates for veterans with ischemic heart disease and chronic heart failure varied widely across the Veterans Affairs (VA) health care system from 2010 to 2014, which could suggest differences in the quality of cardiovascular health care provided by VA medical centers.

Heart failure: The Alzheimer's disease of the heart?
Similar to how protein clumps build up in the brain in people with some neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, protein clumps appear to accumulate in the diseased hearts of mice and people with heart failure, according to a team led by Johns Hopkins University researchers.

Read More: Heart Disease News and Heart Disease Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.