The value of interval training and changing up routines has been substantiated for more demanding exercise programs, so why couldn’t the concept also apply to simply walking? It does, say researchers, who also found that an individual’s naturally “preferred” walking speed varies depending on how far he or she has to walk.
According to a small-scale study published in the September issue of Biology Letters, walking at varying speeds requires a 6% to 20% higher metabolic cost than walking at a constant rate, and the acts of starting and stopping alone could account for between 4% and 8% of the caloric costs of a walking episode. They assert that those starts, stops, and fluctuations aren’t always considered when calculating the caloric burn associated with walking.
The findings are based on research involving 16 healthy young adults (average age—23) who were asked to walk on a treadmill set to a constant speed, and then instructed to increase or decrease their pace—to walk toward the front or allow themselves to slow to the back of the treadmill—at varying intervals. Researchers used 2 models to evaluate energy consumption—one based on kinetic energy fluctuations and the other the inverted pendulum model—and were able to identify metabolic rate increases through both.