In today’s age of smartwatches and Fitbits, it’s hard to go for more than a few hours without taking a sneaky peak at your daily step count. Whether it’s the endorphin rush from the celebratory ping to inform you that you’ve hit 10,000 steps, or the nagging sense of shame that comes with the realisation you’ve done less than 2,000 – as happens on some of my busier days glued to my desk – step counts have become part of our lives.

But they’re not just a gimmick. Research is increasingly showing that your daily step count, especially when averaged out across months and years, makes a huge difference to your disease risk and how long you can expect to live. And the case for not moving more makes for sober reading: according to the Government’s official statistics, physical inactivity is responsible for one in six otherwise preventable deaths.

Monitoring step counts makes it easier to track whether we’re being active or not. But while 10,000 is often seen as the magic number, it originates from a Japanese marketing campaign ahead of the 1964 Tokyo Olympics, rather than hard science.

So how can increasing your step count make a difference to your health and how do different thresholds reduce your disease risk? And, perhaps more importantly, what really is the optimal number you should be aiming to hit a day?

Walk 2,000-3,000 to reduce your risk of heart disease

Two years ago, an international scientific collaboration published one of the largest studies so far to examine the long-term relationship between step count and health. Combining data from more than 111,000 individuals from various electronic health records, it indicated that the lower limit for health benefits lies in the range of 2,000 to 3,000 steps per day. This equates to just over a mile of total walking from the moment you wake up to when you go to sleep.

The benefits appear most acute when it comes to heart health. Published in the Journal of The American College of Cardiology, it suggested that between 2,517 and 2,735 steps per day already reduces risk of cardiovascular disease by 11 per cent compared to those who did just 2,000 steps.

Similar findings emerged from another study published last year by researchers at the University of Sydney. Based on data from more than 72,000 British people in their early 60s, it showed that anything beyond 2,200 steps per day will already make some difference to your heart health and even your short-term risk of dying from another cause.

“We ideally would want 8,000 to 10,000 steps a day, but for people who are inactive, that amount may seem like a mountain and unachievable,” says Matthew Ahmadi, a researcher at the University of Sydney. “It’s about setting initial targets that are achievable, and then gradually working your way up to more daily steps as you build up your capacity to handle more activity.”

Walk 4,000 steps to reduce your risk of dementia

Hitting 4,000 steps a day, based on the Sydney research, can reduce your risk of a premature death from any chronic disease by 20 per cent, particularly if you’re middle aged. But one of the most crucial things about reaching the 4,000-5,000 daily step count is that it starts to reduce your risk of cognitive decline.

Three years ago, a study of more than 78,000 Britons aged 40 to 79, who were regular smartwatch or Fitbit wearers, showed that 3,800 steps appears to be the minimum daily dose of exercise required to preserve your mental faculties. People who averaged this number of steps each day were found to have a 25 per cent lower risk of dementia compared with those who did less.

“This step count equates to roughly 35-45 minutes of light to moderate intensity walking per day, depending on your pace, which aligns well with [public health] guidelines,” says Dr Borja del Pozo Cruz, a scientist at the European University of Madrid, who carried out the study. “This is likely because of improved blood flow to the brain, reduced brain inflammation, better metabolism of glucose in the brain, and an increase in beneficial brain chemicals which stimulate neuron growth.”

Walk 7,000 steps to lower your risk of depression

This seems to be the threshold at which the benefits become even more significant. 7,000 steps are equivalent to just over three miles of walking, and it seems to be highly relevant for mental wellbeing.

A new study published in December – which collated research from 33 different studies, comprising around 100,000 people – found that those who take 7,000 steps per day have a 31 per cent lower risk of depression. “7,000 steps is starting to be considered a more active lifestyle, while less than 5,000 steps is a sedentary lifestyle,” says Dr Bruno Bizzozero Peroni, a researcher at the University of Castilla-La Mancha who authored the study. “It definitely seems that somewhere between 7,000 and 10,000 steps has a protective effect against depression, while at the moment there doesn’t appear to be any evidence of additional benefits for mental health of doing more than 10,000 steps.”

An average of 7,126 steps per day has also been shown to reduce risk of cardiovascular disease by 51 per cent, compared with people who did just 2,000 steps.

So do you really need to reach 10,000 steps per day?

This target which equates to around five miles of walking, or an hour and 40 minutes, if you were going to do the full amount of steps in one go can seem somewhat daunting. But as so often is the case in health and medicine, the answer is somewhat complex.

Around 9,800 steps per day has been found in some studies to be the ‘optimal dose’ of exercise to lower risk of dementia. But as with depression, it appears that you can still substantially reduce your risk of various chronic diseases, with a little less.

For example, some have found that approximately 8,800 steps per day reduces risk of premature death from a whole range of diseases by 60 per cent.

“More steps means better blood vessel function, less inflammation, and enhanced brain plasticity – the formation of new connections in the brain – which are crucial for cognition,” says Dr Del Pozo Cruz.

All this means is that 10,000 steps is not necessarily the magic number after all. It appears that 9,000 is more than sufficient.

How many steps should I do a day to lose weight?

Losing weight requires you to be in calorie deficit, so Dr Ahmadi points out that steps alone aren’t sufficient, you also need to cut down on the amount you’re consuming. “However, what we do know is that activity can improve our cardiometabolic health even if you don’t lose weight,” he says.

While research has shown that reaching 10,000 steps per day will increase your chances of losing weight, the more important aspect with weight loss is the intensity of exercise, not the number of steps. Researchers advise more vigorous intensity exercise but it doesn’t have to be jogging or playing sport.

“You can get to vigorous intensity, just with brisk walking,” says Catrine Tudor-Locke, a professor at the University of North Carolina at Charlotte. “It doesn’t have to be running.”

Does walking burn a lot of calories?

This largely depends on your weight, as the more body fat you’re carrying, the more calories you’re likely to burn, as the body uses up more energy when it comes to moving additional weight stored in the form of fat tissue.

However, the below represents a rough guide. For example, 50 calories represents approximately two cups of cherry tomatoes, a chunk (or 50 grams) of cheddar cheese comes to 200 calories, and a Greek salad is 400 calories.