What does it mean that exercise chains?

The sequence from trigger to warm-up to workout to cooldown benefits from chaining.

Example: Two people both want to exercise at 6 a.m. before work. The first wakes up, lies in bed weighing whether today is a gym day or a run day, checks the weather, scrolls through a workout app comparing options, realizes fifteen minutes have passed, feels the window closing, and decides tomorrow will be better. The second wakes up, and her feet hit the floor next to the running shoes she placed there last night. She puts them on — that is the only decision. Shoes trigger standing, standing triggers walking to the door, the door triggers the three-block warm-up walk, the walk triggers the run, the run triggers the cooldown stretch on the porch, the stretch triggers the glass of water waiting on the counter. She is back inside, showered, and drinking coffee before the first person has closed the workout app. The difference is not motivation. It is that the second person removed every decision except the first one and let the chain carry the rest.

Try this: Map your current exercise behavior as a chain. Write each step from the moment you first think about exercising to the moment you finish and transition to the next activity. Circle every point where you currently make a decision — what to do, where to go, how long, how hard. For each decision point, write a pre-committed default that eliminates the decision. Then identify the first physical action in the chain (the one that, if it happens, makes the rest dramatically more likely) and engineer a trigger for it: lay out the clothes, place the shoes, set the bag by the door. Test the redesigned chain three times this week and note where it flows and where it stalls.