THERE IS AN LINK BETWEEN ROAD TRAFFIC NOISE and high blood pressure (hypertension). This association remains after controlling for air pollution. Those are the findings of a new thought-provoking study using data from the United Kingdom Biobank.

I very much enjoy walking outdoors, preferably around trees. I prescribe physical activity (such as ambulation) to my patients. Movement helps reduce the risk of everything from heart attack and stroke to early mortality.

Stanford University (USA) researchers discovered that individuals walking 90 minutes in a natural area (compared with subjects who walked in a high-traffic urban setting) had lower activity in a brain region associated with depression.

I Prescribe Nature to My Patients

I OFTEN PRESCRIBE NATURE TO MY PATIENTS, as exposure to the natural world has been associated with improvements in well-being. Read more here:

Many others have opined on the subject.

“Her pleasure in the walk must arise from the exercise and the day, from the view of the last smiles of the year upon the tawny leaves and withered hedges, and from repeating to herself some few of the thousand poetical descriptions extant of autumn — that season of peculiar and inexhaustible influence on the mind of taste and tenderness — that season which has drawn from every poet worthy of being read some attempt at description, or some lines of feeling.”
― Jane Austen, Persuasion

Sir Noël Peirce Coward (16 December 1899–26 March 1973) was an English singer, actor, composer, and playwright known for his wit, flamboyance, and what Time magazine called “a sense of personal style, a combination of cheek and chic, pose and poise.” Here is his witty take on walking:

“I like long walks, especialy when they are taken by people who annoy me.”
― Noel Coward

Last week, I logged nearly 25,000 steps walking in New York City in one day. But are there downsides to my practice of walking? What are the negative effects of road traffic and air pollution?

Road noise and high blood pressure

Today, I want to share with you the results of the first large prospective study directly analyzing the effect of road traffic noise on the incidence of newly-diagnosed high blood pressure (hypertension).

Let’s cut to the takeaway message:

The study offers a higher level of evidence that we should modify road traffic noise and pollution from the individual and societal levels to improve cardiovascular health.

To better understand the association between long-term road traffic noise exposure and a new diagnosis of high blood pressure, researchers conducted a prospective population-based analysis in UK Biobank.

First, they estimated road traffic noise at a baseline residential address. Second, the researchers used medical records to find incident hypertension. Finally, they estimated high blood pressure risk for 240,000 subjects free of hypertension at baseline, adjusting for potentially confounding factors.

After a median of 8.1 years, the researchers discovered a dose-response relationship: The higher the noise exposure, the greater the risk of having a diagnosis of hypertension.

For every 10 decibel increase (in average 24-hour road traffic noise level), there was a 1.07 times rise in the chances of having high blood pressure. The researchers adjusted the data for fine particles (PM2.5) and nitrogen dioxide (NO2) exposure.

Exposure to air pollution and traffic noise exposure led to the highest high blood pressure risk.

Summary — Road noise and high blood pressure

Chronic exposure to road traffic noise appeared to be associated with a higher risk of receiving a hypertension diagnosis. The effect estimates were stronger in the presence of higher air pollution.

Study author Jing Huang says that “they were a little surprised that the association between road traffic noise and hypertension was robust even after adjustment for air pollution.”

I will stay indoors during higher pollution times unless I can head into one of the many forested areas in Seattle.