Sometimes, within the first 30 seconds or so when you start exercising, you feel slow, and almost winded. But, as you ease into the workout, the movements become more comfortable. Ever wonder “Why Do the First Few Moments of Working Out Feel So Hard?”
University of Utah researchers found that as your body goes from standing still (or walking) to running (or engaging in other high intensity exercise), it takes a few moments for your body and cells to adapt to what your body is doing. It’s almost the equivalent of going from 0-60 in your car. If you did that, it would take a few seconds for your car’s rpms to level off and for the car to run smoothly. Your body goes through a similar conversion period because there is simply not enough energy at first.
Essentially, as you take off running, your body relies on substrates from glucose metabolism for energy (it also uses stored ATP, but this diminishes quickly). Yet, your body hasn’t fully adapted to the demands of moving your arms and legs, so it takes longer to process the substrates. In this article from Runner’s World, writer Alex Hutchinson calls the time it takes “the metabolic reactions within the muscle cells that produce aerobic energy to get up to speed” “metabolic inertia.” This is why as you ease into the workout, your body adapts to the demands for exercise and it becomes easier…at least for a little while.
You can improve the time it takes for your body to overcome the “metabolic inertia” period by exercising more. As you train, your body becomes more efficient at creating and storing energy and this in turn reduces that sluggish period so you start to dread those first few moments less and less.