Winter Training: Navigating Indoor and Outdoor Cardio Environments
Taking your cardio indoors this winter? Explore how the setting can change pacing, effort, and enjoyment on your runs and rides.
Moving a run or ride indoors changes the setting in which you judge your effort. Three studies illustrate different parts of that change: perceived running speed, cycling power variability, and enjoyment. They do not establish a single conversion between indoor and outdoor workouts.
Perceived speed on a treadmill
A 2012 study of 21 participants compared three-minute track runs with a treadmill run. With the treadmill speed display hidden, participants adjusted its speed until it seemed to match their preceding, self-selected track speed. They selected a significantly slower speed on the treadmill than on either track run.
The researchers suggested a mismatch between observed and expected visual flow as a likely explanation authors' interpretation. This was a perceived-speed matching task. It did not test whether matching an outdoor pace produces the same perceived effort or physiological intensity indoors, and it does not supply a universal treadmill-speed adjustment.
Cycling power varies with the setting
In a 2019 study, twenty competitive male cyclists completed maximal 20-minute time trials on an outdoor racing circuit and an indoor laboratory ergometer, seven days apart in randomized order. The same bicycles and power meters were used in both conditions.
The researchers detected no significant difference in mean power output: 280 watts indoors and 284 watts outdoors. That result does not prove the conditions were equivalent. Within-person power variability, measured as a standard deviation, was greater outdoors: 69 watts compared with 33 watts indoors power-output results.
The authors suggested that external constraints contribute to the greater fluctuations outdoors. The study did not isolate the individual effects of wind, terrain, or balance. Its results describe these specific time trials in competitive male cyclists, rather than every recreational ride or indoor setup.
Enjoyment and intentions after a brief ride
A 2024 randomized crossover trial compared brief outdoor cycling with indoor cycling using virtual reality and enhanced reality in 31 healthy young adults. After each condition, researchers assessed enjoyment, intrinsic motivation, intention to perform green exercise, and heart rate.
Outdoor sessions received higher enjoyment, intrinsic-motivation, and green-exercise-intention scores than either indoor condition trial results. These were immediate responses and stated intentions. The trial did not measure long-term exercise adherence or establish that everyone should prioritize outdoor training. Nor did it compare the technology-assisted sessions with a basic indoor session without that technology.
The useful distinction is between the outcomes being measured. Perceived speed is not physiological intensity; average power is not power variability; and enjoying one brief session is not the same as maintaining a routine over months. These studies help explain why the indoor and outdoor experience may differ, while leaving individual scheduling decisions and long-term outcomes unresolved.