Does walking build muscle, burn fat, or both?

Yes, yes, walking isn’t a new fitness craze, but everybody’s doing it. It’s low impact, accessible, and free – but from a fitness perspective does walking build muscle?

In a study on global participation rates in sport, walking was found to be the most popular physical activity among adults in four of six regions including the Americas, Eastern Mediterranean, Southeast Asia and the western Pacific – which is great but is it actually any use to us, beyond getting away from your desk for a few mins?

What happens to our bodies when we walk?

“From a physiological perspective, walking is a whole body activity,” says Professor Brian Carson, exercise physiologist at the University of Limerick, and head of science at Whole Supp. “When we walk we use our muscles to propel us which increases our energy expenditure, thus increasing the metabolic demands placed on our muscles and the body as a whole.”

As with any exercise, our breathing speeds up in order to deliver more oxygen to our muscles. But, because walking is relatively steady state – i.e. not too taxing – we’re unlikely to get out of breath unless there’s an added stressor, like when we’re walking uphill, or at a faster pace.

There’s also a neurological effect. “Our brain and nervous system become more active as we take in and process sensory information from the environment around us and from the movement itself, while at the same time providing stimulatory output to the muscles in a coordinated sequence to help us move fluently,” says Carson.

In fact, a 2014 Stanford University study determined that walking provides a significant boost to creative thinking during and after the activity, with an 81% increase in creativity measured in a divergent thinking test compared to when sitting down. Walking outside promoted the highest levels of creativity.

And, while all of this is happening our body is taking nutrients from our muscle, fat and liver tissues in order to convert them into energy.

Getting from A to B aside, how else does walking help?

Unless you’re dragging a petulant dog after you, walking is generally considered a good way to unwind. This is because when we walk at a comfortable pace, our parasympathetic nervous system is activated, triggering a reduction in cortisol, the stress hormone.

As well as clearing our heads, walking can help our brains grow. A 2011 study involving 120 older adults found that regular aerobic exercise, such as walking, increased the size of the hippocampus and raised levels of brain-derived neurotrophic factor, or BDNF. “This is like fertiliser for your brain, helping brain cells to grow, strengthen and communicate more effectively with each other,” explains Abigail Ireland, peak performance strategist at Understanding Performance.

What’s more, in a meta analysis carried out at the University of Limerick, Carson’s colleagues found that one of the key benefits of walking is to interrupt sedentary behaviours such as sitting.

“Interestingly, the speed at which we walk has an influence, with faster walking resulting in better health outcomes such as predictors of all cause and cardiovascular mortality,” Carson adds.

So, does walking build muscle or not?

Gym lore goes that cardio kills gains as our bodies metabolise our muscles for energy. But can walking actually build size?

It turns out, not really – although Carson points out that in a study where step counts were reduced to below 1500 steps per day, participants saw significant reductions in leg lean mass and muscle protein synthesis was reduced by 28%, even after a high protein meal. That said, another study found some walking was better than sitting all day. Ireland points to a third study which found that walking combined with resistance training is much more effective in maintaining muscle mass.