Even brief, functional bouts of aerobic activity, such as climbing stairs for 20 seconds, can ultimately improve one's cardiorespiratory fitness, according to a new study published in the Applied Physiology, Nutrition, and Metabolism journal.

"Do Stair Climbing Exercise 'Snacks' Improve Cardiorespiratory Fitness?" monitored 24 healthy but mostly sedentary college students at McMaster University in Ontario, Canada. The subjects were split into a non-exercise control group and an exercise test group.

Under observation, members of the test group swiftly ascended a three-flight, 60-step staircase three times a day—an exercise "snack," as described in the study. This 20-second activity was preceded by a warm-up of jumping-jacks, air squats and lunges, and was followed by a cooling-down walk.

After six weeks, the researchers found that VO2 max and peak power output were higher in the test group, equating to a 5 percent increase in overall aerobic fitness.

The study states: "The present work nonetheless shows that the stair climbing exercise snacking protocol was feasible, and well-tolerated by sedentary individuals, and improved functional performance."

The researchers suggest that future studies should investigate multiple snacking protocols with varying recovery time, as well as measure the protocol's effect on blood pressure and glycemic control.

Previous related studies were primarily conducted on stationary bikes in labs, and the McMaster University researchers wanted to take a more functional approach.

"We've been increasingly interested in translating this out of the lab and making this more practical and accessible to people," lead study author Dr. Martin Gibala told Insider. "We thought, well, stair climbing is a great way to apply this. Many of us work in an office tower or live in apartment complexes, so stairs are readily available."

Other recent studys have said that regular aerobic activity can improve the brain's functional age and help slow physical frailty later in life.