Although 10,000 a day has long been touted as the number of steps to aim for to derive health benefits, the evidence for this number was scant until research from the University of Sydney was released earlier this year.
Published in British Journal of Sports Medicine, the research found that 10,000 steps a day can reduce risk of death by 39 per cent and cardiovascular disease by 21 per cent, even if the rest of the time is spent being sedentary.
Researchers used data on 72,174 individuals (average age 61 and 58 per cent female) from the UK Biobank study – a major biomedical database – who had worn an accelerometer device on their wrist for seven days. The daily step count and time spent being sedentary was calculated and then the health trajectory of the participants was followed up via hospitalisation data and death records.
The lowest step count of 2,200 steps a day was taken as the comparator for assessing the impact on death and CVD events of increasing step count.
Participants who were sedentary for less than 10.5 hours a day were classified as low sedentary time and those who were sedentary for more than 10.5 hours/day or more were considered to have high sedentary time.
Adjustments were made to eliminate biases, such as excluding participants with poor health, who were underweight, or had a health event within two years of follow-up. Researchers also took into account factors such as age, gender, ethnicity, education, smoking status, alcohol consumption, diet and parental history of CVD and cancer.
9,000 is the magic number
Over an average 6.9 years follow up, 1,633 deaths and 6,190 CVD events occurred. After taking account of other potential influences, the authors calculated that the optimal number of steps per day to counteract high sedentary time was between 9,000 to 10,000 steps. This activity lowered premature mortality risk by 39 per cent and incident CVD risk by 21 per cent. In both cases, 50 per cent of the benefit was achieved at between 4,000 and 4,500 steps a day.
Lead author and research fellow, Dr Matthew Ahmadi, says: “This is by no means a get out of jail free card for people who are sedentary for excessive periods of time, however, it does hold an important public health message that all movement matters and that people can, and should, try to offset the health consequences of unavoidable sedentary time by upping their daily step count.”
Senior author, Professor Emmanuel Stamatakis, says: “We hope this evidence will inform the first generation of device-based physical activity and sedentary behaviour guidelines, which should include key recommendations on daily stepping.”
The study had some limitations: it was observational so couldn’t establish direct cause and effect and other unmeasured factors may have affected the results.
However, researchers still conclude any amount of daily steps above 2,200 is associated with lower mortality and CVD risk, regardless of the amount of time spent being sedentary.
