Blanketed by darkness and zipping past streetlamps, night runners may feel as though their nocturnal hours award swifter speeds. But does logging midnight miles actually inspire greater speeds, or is the quickened pace merely a mind trick?

A Run on the Dark Side — Why It Matters

Donning sneakers at sunrise rarely seems more appealing than basking in bed — even for the most dedicated runners. And for some, nighttime running, if done safely, can be a more convenient cardio fix. Besides the less-crowded paths, cooler temperatures, and forgiving lighting of the moon (see ya, sweat stains and trouble spots!), late night escapades may prompt runners to feel as though they are running at a faster pace [1]. Move over, Mr. Bolt.

But, not so fast… Research suggests a runner’s perception of increased speed at night is just that: a perception [2]. The brain perceives the body’s speed based on incoming visual cues from its surroundings [3] [4]. One such speed cue is motion parallax (for example, when traveling in a car, nearby objects seem to fly by more quickly than objects further away) [5]. The same experience applies to running, biking, scootering, crab-walking, and other forms of linear motion (and also explains why you feel zippier when running on ground than on a treadmill) [6] [7].

The reason why? To assess speed, the brain compares the relative speed of objects in both extremes of distance (think: the planted flowers along the path versus the distant horizon or skyline). But at night, the darkness limits our vision making the “slower-moving” objects in the distance invisible [8]. So our only gauge for speed is the road sign or the shadowed trees we just blew by (or wait, was that the boogeyman?!).

Night Sweats — The Answer/Debate

While the piqued pace may be a nighttime illusion, some research suggests evening workouts are indeed more energy-efficient, powerful, and allow for higher endurance compared to morning workouts [9] [10]. But how? Studies chalk this up to circadian rhythms and the fact that our body’s metabolism, mood, appetite, and other functions peak at different times of day. For example, the average person’s core body temperature peaks in the evening, which loosens up muscles and makes them more ready for movement [11]. Similar research suggests that lung function, alertness, and flexibility are also enhanced in the evening [12] [13]. The result? The differences in a person’s AM to PM exercise capacity may be like night and day.

So are circadian rhythms likely to help shave off seconds from a mile time? Maybe, but only if the run falls within circadian rhythm peak hours, and for most people that aligns with the early evening (between 4 and 6pm) [14]. Even still, the change in performance is minimal. And a jog under the stars after the Nightly News likely won’t add that much speed either — except in our heads. But a confidence boost never hurts. And night owls can hit the snooze button feeling a little less guilty for skipping that morning run — the night awaits. 

The Takeaway

There is no evidence that proves running at night and/or in the dark directly improves speed. Instead, a visual illusion is likely responsible for the deceiving (yet confidence-boosting) sensation. 

This article has been read and approved by Greatist Experts Vicki Vara and Michael George.

Photo by Marissa Angell