Why Does Matt Walker Bike Facing the Morning Sun?

Matt Walker starts workouts around 7:45 or 8 in the morning on a spin bike facing an east window so exercise and daylight arrive together, even though the time he would rather exercise is around 1 in the afternoon. Daylight and exercise are both cues that align the circadian rhythm and reset it each day.

Walker is neither a strong morning type nor a strong evening type. His preference is a workout sometime in the middle of the day, around 1 in the afternoon. He still works out most days at a gym he chose for huge amounts of window exposure facing east, and he starts with cardio on a spin bike facing a window. In California, sunlight usually comes through. On a cloudy day the intensity of the light coming through is still splendid. He matches the session to circadian light exposure rather than to the hour he would pick just to crush a workout, because he also wants to get on with the working day.

The earlier hour stacks movement and morning light, two wakefulness cues, into one session.