It turns out that the advice to walk 10,000 steps a day was originally a marketing tool and didn’t originate from science. The number originated as a means of promoting the first commercial pedometer! Min-Lee an epidemiologist at Harvard University found that mortality rates decrease up to 7,500 steps a day, beyond which no additional mortality benefits was observed.
Tessa Strain at the University of Cambridge studies the epidemiology of physical activity and reminds us that step counts are really a rough proxy for energy expenditure, so not all steps are equal. If you have done a few thousand steps but they were brisk and uphill, there is no need to be averaging anywhere near as many steps. In short, walking each day will lengthen your life but there is no need to set yourself a specific target and remember that 10,000 steps was just a marketing ploy designed to sell pedometers.