London’s air pollution problem means that for the city’s older adults exercise counts for nothing

A study has concluded that even short-term exposure to air pollution in built up areas like London’s Oxford Street can negate the beneficial health effects of exercise in older adults.

The research by Imperial College London and Duke University, and published in The Lancet, adds to the growing body of evidence showing the negative impacts of urban air pollution on cardiovascular and respiratory health, and highlights the need for stricter air quality limits and greater access to green spaces.

“It’s possible that studies such as this could support new air quality limits, it shows that we can’t really tolerate the levels of air pollution that we currently find on our busy streets,” said senior author Fan Chung, Professor of Respiratory Medicine and Head of Experimental Studies Medicine at National Heart & Lung Institute at Imperial College London.

Image courtesy of Ron Porter

For the study, funded by the British Heart Foundation, researchers recruited 119 volunteers, aged over 60, who were either healthy, had stable Chronic Obstructive Pulmonary Disease (COPD) or had stable heart disease.

The volunteers were then split into two groups. One of the groups walked for two hours in a relatively serene part of Hyde Park, while the second group walked along a busy stretch of Oxford Street – which has regularly breached air quality limits set by the World Health Organization.

Physical measurements were taken before and after the walks to show the effects of the exercise on cardiovascular health, including measurements of lung volume exhaled, blood pressure and the degree to which the blood vessels could expand.

Environmental measurements were also collected, to track pollution levels and volunteers’ exposure.

Image courtesy of David Holt

Analysis revealed that all participants benefitted from a stroll in the park, with lung capacity improving within the first hour and a significant lasting increase for more than 24 hours in many cases.

By comparison, a walk along Oxford Street led to only a small increase in lung capacity in participants, far lower than recorded in the park.

Blood flow also increased after exercise, with decreases in blood pressure and an increase in heart rate. Arteries became less stiff in those walking in Hyde Park with a maximum change from baseline of more than 24% in healthy and COPD volunteers, and more than 19% in heart disease patients.

This effect was drastically reduced when walking along Oxford Street, however, with a maximum change in arterial stiffness of just 4.6% for healthy volunteers, 16% for those with COPD and 8.6% for heart disease.

“These findings are important as for many people, such as the elderly or those with chronic disease, very often the only exercise they can do is to walk,” said Chung.

“Our research suggests that we might advise older adults to walk in green spaces, away from built-up areas and pollution from traffic.”

Bitcoin Now the Sixth Most Valuable Currency in the World

The cryptocurrency Bitcoin has risen to become the sixth most valuable currency in the world by the amount in circulation, after a series of surges saw it rise to a value over $11,000 a coin.

As a result, the total value of all Bitcoins in circulation is considerably more than the equivalent of several major currencies.

According to a report by, the current value of all Bitcoins is currently approximately $180bn. By contrast, all the UK Pound Sterling banknotes and coins in circulation currently total only $103bn, while the total value of all Canadian and Australian currency in circulation now is $59bn and $55bn respectively.

As a result, 54% of the world’s population lives in countries with in-circulation currencies lower than the total value of Bitcoin.

2017 has seen Bitcoin undergo a dramatic surge in price. At the very start of the year, the cryptocurrency was worth just under $1,000 a coin, and rose relatively steadily over the next few months to reach $3,000 in June.

However, the last few months has seen more marked growth, it hitting $5,000 for the first time in October, $8,000 in November and $10,000 in December.

If it continues its current pace of growth it will hit $15,000 within a month, which would make it the fifth most valuable currency in the world, ahead of India’s Rupee.

Climbing much higher than that, however, will be a challenge. To beat the Euro to second place, Bitcoin will need to rise to an incredible $72,300, and to knock the US Dollar off the top spot, Bitcoin will need to reach $85,160.

While there are other cryptocurrencies attracting investment, none of the others have reached the giddy heights of Bitcoin, with just Ethereum and Bitcoin Cash reaching the top 20 world currencies.

Ethereum has a current total value of $44bn, making it the 17th most valuable currency in the world, while Bitcoin Cash is at the 20th place with a current total in-circulation value of $24bn.

Lesser known cryptocurrency Ripple follows in 21st place, with a value of $10bn, making it worth more than all Swedish Krona ($9bn) and all South African Rand ($6bn).