At maximum effort, the treadmill burned about 2 more calories per minute than the stair climber in a small study of 30 men. The Conversation reviewed evidence comparing Treadmill Running with Stair Climbing. That included the small calorie study and other comparisons of fitness gains. The calorie result came from all-out exercise, not a typical easy gym session. It does not show that everyone will burn the same extra amount. Why might the treadmill burn more? The article suggests running uses more muscles across the body, including the arms. On a stair climber, the upper body does less work. Holding the handrails also leaves less room for arm movement. This is a possible explanation, not proof of the cause. Other comparisons add some useful context. At the same effort relative to each person's ability, stair climbers produced lower heart rates. People also used less oxygen, suggesting less demand on the heart and lungs. Yet another comparison found improved fitness and similar gains in running performance. A higher calorie burn does not tell the whole fitness story. For BioSocial members, this is a reason to compare more than one workout number. Logs of Active Calories Burned, session length, machine settings, and effort can help frame community discussions. Keeping easy sessions separate from all-out efforts makes those comparisons more useful. Changes in your running pace over time offer another way to track progress. If you use both machines, what differences have you noticed in your workout numbers and running progress?