The findings were independent of known cardiovascular risk factors, but strongest in women, the under 60s, those who weren’t obese, and those with pre-existing long term conditions.

Heart rhythm abnormalities (arrhythmias) are common, note the authors, with atrial fibrillation alone doubling in prevalence over the past 3 decades to reach nearly 60 million cases worldwide in 2019, read the University of Glasgow website.

As these abnormalities are associated with heightened risks of cardiovascular disease, sudden cardiac death, and disability, pinpointing modifiable risk factors is essential to stave off the toll taken on health, they add.

While walking pace is associated with lower risks of cardiovascular disease and death, few studies have looked at its potential impact on cardiac arrhythmias.

The researchers therefore looked at the potential impact of different walking speeds while exploring the potential influence of metabolic factors and inflammation, as well as accounting for cardiovascular risk factors, such as age, sex, obesity, smoking, alcohol intake, and pre-existing long term conditions.

They drew on 420,925 UK Biobank participants for whom walking speed data was available from questionnaire responses. The amount of time spent walking at different paces—derived from activity tracker readings—was available for 81,956 of them.

A slow pace was defined as less than 3 miles an hour; steady/average pace as 3–4 miles/hour; and a brisk pace more than 4 miles/hour.

The average age of the participants was 55; more than half (55%) were women and most (97%) were White.

Overall, 27,877 participants (just over 6.5%) reported a slow walking pace; 221,664 (53%) an average walking pace; and 171,384 (41%) a brisk walking pace.

During an average monitoring period of 13 years, 36,574 (9%) of participants developed cardiac arrhythmias: 23,526 atrial fibrillation; 19,093 other cardiac arrhythmias; 5678 abnormally slow heart rate; and 2168 ventricular arrhythmias (abnormal rhythms originating in the lower chambers of the heart).

Participants with a faster walking pace were more likely to be men, live in less deprived areas, and have healthier lifestyles. They also had smaller waists, weighed less, had better grip strength, and lower levels of metabolic risk factors, including blood fats and fasting glucose, as well as lower levels of inflammatory activity, and fewer long term conditions.

After accounting for potentially influential background demographic and lifestyle factors, average and brisk walking paces were associated with significantly lower (35% and 43%, respectively) risks of all heart rhythm abnormalities compared with a slow walking pace.

And they were associated with lower risks of atrial fibrillation (38% and 46%, respectively); and of other cardiac arrhythmias (21% and 39%, respectively) compared with those whose walking pace was slow.

Some 4117 of the participants with activity tracker data developed arrhythmias. Those who spent more time walking at a brisk pace were generally younger, more likely to be white and male, and less deprived. They had generally healthier lifestyles, and were healthier, overall.

While the amount of time spent walking at a slow pace wasn’t associated with the risk of developing heart rhythm abnormalities, but more time spent walking at an average or brisk pace was associated with a 27% lower risk.

Overall, around 36% of the association between walking pace and all heart rhythm abnormalities was influenced by metabolic and inflammatory factors.

The observed associations were independent of known cardiovascular risk factors, but were strongest in women, the under 60s, those who weren’t obese, those who had high blood pressure, and in those with 2 or more long term conditions.

This is an observational study, and as such no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that part of the study relied on self report while the study participants don’t reflect a broad spectrum of ages and ethnic backgrounds.

Professor Jill Pell said: “This study is the first to explore the pathways underpinning the association between walking pace and arrhythmias and to provide evidence that metabolic and inflammatory factors may have a role; walking faster decreased the risk of obesity and inflammation which in turn reduced the risk of arrhythmia.”

She added: “This finding is biologically plausible because cumulative epidemiological studies have shown that walking pace is inversely associated with metabolic factors, such as obesity, HbA1c [fasting glucose], diabetes, and [high blood pressure] which, in turn, are associated with the risk of arrhythmias.”