Hours of (Cycling) Power

An inside look at how the way you feel and ride can vary by time of day.

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What’s the best time of day for cycling? The smart alecky answer is “whenever you’ll do it”, but the truth is a bit more complicated. It depends, in part, on what your goals are and whether you’re naturally more of a morning person (a lark) or a night-lover (an owl).

We all have ups and downs in the way we feel and function throughout the day, and our physical performance is no exception. Our bodies’ circadian rhythms (our internal clocks) are influenced by exposure to light and dark, and they affect everything from our blood pressure and metabolism to our hormonal and body temperature fluctuations.

As a result of these physiological shifts, there are often predictable patterns to people’s pain tolerance (it’s higher in the early morning), alertness and reaction time (it rises in the mid-to-late morning), and muscle strength, short-term power output, and flexibility (they peak in the early evening). Here’s a look at specific hours of power for cycling:

It May Feel Easier Earlier in the Day

A 2014 study from the University of Cape Town in South Africa found that when trained cyclists who were self-professed morning types cycled at 60, 80, and 90 percent of their maximum heart rate at five different times of day (6 a.m., 10 a.m., 2 p.m., 6 p.m., and 10 p.m.), they reported higher ratings of perceived exertion when cycling at all three intensities in the evening (both 6 p.m. and 10 p.m.) than during the other exercise sessions. This perceived difference was despite the fact that there was no variability in their power output, speed, or cadence.

In other words, the same workload simply felt considerably harder to these larks (morning types) in the evening.

Meanwhile, a study published in the June 2006 issue of the International Journal of Sports Medicine had cyclists perform all-out sprints followed by brief recovery periods in the morning and in the evening on separate days; during the experiment, researchers measured various aspects of the riders’ effort (pedaling rate, power output, and the like) and physiological function (such as voluntary contraction of knee extensor muscles and neuromuscular efficiency in the legs).

While the patterns of fatigue were similar at both times of day, the cyclists were able to recover their neuromuscular function more quickly between sprints in the morning than the evening.

Pedaling Pace May Increase in the Afternoon

Research on whether the time of day affects cyclists’ performance on time trials has yielded mixed results. In one study involving competitive cyclists, researchers examined whether circadian rhythms affected their performance on 15-minute time trials at three different times of day—between 8 and 10 a.m., 2 and 4 p.m., and 8 and 10 p.m.—and found that power output was highest during the morning session and lowest during the afternoon session but the difference was minor. By contrast, another study found that when cyclists did a 16.1-km. time trial after a 25-minute warm-up (at 60 percent of their peak power) at 7:30 a.m. and 5:30 p.m., they were significantly faster in the late afternoon.

In another study, researchers from the U.K. had eight women cycle at a high-intensity aerobic effort to the point of exhaustion at 6:30 a.m. and 10 p.m. after completing a 5-minute warm-up.

They found that despite there being no difference in the riders’ level of perceived exertion, the women performed at a higher intensity in the evening. Another study found that cyclists’ oxygen uptake efficiency (a measure of cardiopulmonary function) was greater between 7 and 8:30 p.m. than it was between 7 and 8:30 a.m.

The Bottom Line

Given all these findings, it’s a bit of a draw as far as the optimal timing goes for cycling. As one aspect of performance goes up, another might come down. Even the potential peaks and valleys in performance may be slightly earlier or later in the day, depending on whether you’re naturally a lark or an owl. There are other factors to consider, too, such as when classes are available, when they’re most crowded, and what suits your schedule.

Some experts suggest that morning cyclists (and other exercisers) are more likely to stick with their routines than those who work out later in the day, and it makes sense if you think about it: After all, if you take a cycling class or do a solo ride first thing in the morning before your work-day starts, nothing has the chance to get in the way of your best-laid plans. Ultimately, your best bet is to synchronize your training program so it’s compatible with your biological clock and your life.

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