The surprising secret to burning more calories while walking

In this sedentary society that so many of us now live in we have to replace olives with other, less tasty snacks to keep in shape and maybe even lose those extra kilos we have gained from our excesses. Nowadays it's all about climbing stairs, taking advantage of the five minutes after going to the toilet to do squats, stretching those calf muscles by going up and down on your heels and toes. However, not everyone likes to do these things. Most people like sport even less, wanting nothing to do with weights, running or even pilates. Still, there is another activity that can get results without the need for gym gear or doing anything out of the ordinary in order to exercise: walking.

We are not going to talk here about the general benefits of walking, there are hundreds of articles already on those. Here we will talk about a new study that shows that marathon exercise sessions are not necessary to see positive results, especially if our main motivation is to lose weight. It has already been made clear that the 10,000 steps a day mantra is relative to the individual body. In fact, researchers from the University of Sydney and the Charles Perkins Centre now suggest that 8,000 steps are more than enough. To this argument we must add results from another piece of research published in late October by the University of Milan, which focuses on how that walk should be done in order to burn more calories.

Strangely enough, the answer is something like 'less is more'. What the Italian researchers have shown is that our body consumes more resources when we start walking. So, if we stop and start on our daily walk, we will increase the number of calories consumed. "It's similar to what happens when we use the car for short distances," says Francesco Luciano, who leads the team of researchers at the university's department of pathophysiology (the study of changes in the human body as a result of disease).

To reach this conclusion Luciano and his fellow researchers - Luca Ruggiero, Alberto E. Minetti and Gaspare Parei - worked with two groups of ten people, each of whom were put on a treadmill or a stair machine under certain conditions, then the team analysed their physiological responses.

The first ones were put to walk in 10-second to 4-minute bursts at a speed of 1.39 metres per second. Between walks they rested for three minutes. The second group climbed stairs in sets of 10, 30, 60, 90 and 240 seconds with a 7-minute recovery period in between.

Why such short durations? Because, as Luciano explains, there has been a lot of research on "the metabolic cost of steady-state walking", but only walking for long periods, not for such short durations. When analysing the data the team realised that, when people walked for 10 or 30 seconds, they needed much more energy to complete each metre than for longer periods of time and distance.

"The example of the car illustrates it perfectly," says Iván Rodríguez, professor of Sports Science and Physiotherapy at the European University of Madrid. When it comes to training, we can train at "low intensity, where the main energy resource is fat" or at "high intensity, when we resort to other energy substrates, such as glucose or phosphagen."

In the first case, we need a long time to metabolise the 'fuel', but we can do it because the exercise is more gentle, so to speak. This is normally the case with walking. In the second case, we are talking about short bursts of exercise in which we give it our all, as with HIIT (high-intensity impact) training. Well, 'walking at intervals' would work in a similar way to HIIT.

"What we saw during the experiment is that, on shorter walks, we are less efficient at converting oxygen into chemical energy," explains Luciano. Their research goes deeper into how healthy walking could be, but it is even more interesting to note that these findings indicate the potential to be more inclusive with such an activity. How? By "understanding the energetic demands of short walks" we can help support "tailor-made" physical activity. For instance, if a person with obesity or mobility problems is unable to walk long distances, a plan based on this study's findings could be made so that they would not need to walk five kilometres in one go, just walk less or walk the five kilometres with more breaks to achieve similar results.