Encourage clients to move at every chance they get, not only during scheduled workouts. Why? Researchers from the University of Texas at Austin found that if overall daily activity levels are too low—even if you exercise during the day—the body becomes less efficient at “burning” (i.e., metabolizing) fat, causing more of it to be stored. This phenomenon is called “exercise resistance.” What this means is that too much inactivity hampers the normal improvement in fat oxidation that occurs after exercise.

Investigators wanted to know what range of daily step counts stimulates the exercise resistance effect. They found that after 2 days of step reduction to approximately 2,500–5,000 steps per day, young, healthy individuals “displayed a 16%–19% decrease in fat oxidation and a 22%–23% increase [in post-meal blood triglyceride levels] the next day.” Study authors concluded that this “suggests that ‘exercise resistance’ occurs in individuals taking approximately 5,000 or fewer steps per day, whereas 8,500 steps per day protects against exercise resistance in fat metabolism.” Future research will examine what the best timing for those steps should be throughout the day.

An important insight is that inactivity influences fat metabolism more powerfully than exercise does. In other words, prolonged sitting blunts the benefits of exercise. Fitness professionals can help by encouraging clients and participants to move more throughout the day and avoid inactivity, in addition to promoting planned physical activity.

The study is available in Medicine & Science in Sports & Exercise (2021; 53 [2], 333–40).

See also: Addressing Exercise Barriers