Go for a late-afternoon or early-evening run as your blood pressure, core body temperature, testosterone and cortisol ratio, joint flexibility, energy levels, and lung function hit a circadian peak. These improve your strength, endurance, and reflex. Contrary to popular opinion, the body is not primed for a morning run, but if you're comfortable with your timing, don't upset your body's rhythm by changing it.
Ever since running began emerging as a mass fitness activity in the United States in the 1960s, many people, irrespective of their age or gender, have adopted it into their daily routine. That’s hardly a wonder, given the benefits running offers—from reducing weight and the risk of cardiovascular diseases to alleviating depression and improving learning and memory—not to mention the ease with which one can embark on this fitness regimen.
When Should You Run?
Do you run as and when the mood strikes you, be it in the scorching midday or in the pitch-dark night? Or do you schedule it at a fixed hour every day? In that case, what’s your pick—morning, noon, evening, or night?
If you are a morning person, you’d most likely go for a jog first thing in the morning to give an active start to your day. But if you’re not, it’s highly unlikely that you’ll force yourself out of bed to run a mile at the crack of dawn. Even if you do, it might be counterproductive, even harmful, with your body remaining stiff and sluggish with sleep inertia.
It’s evident that other than practicalities like time available, road condition, and weather, the factor that most influences your choice of the time of day is your physical ability—not just the flexibility but also the alertness. Whether you are running because you love to run or because it’s part of your fitness regimen, you can optimize your performance by finding a time that best suits your body’s natural rhythm. For this, you need to leverage your circadian rhythms and your body temperature as these are the two most important factors influencing your performance.
Factors Influencing Your Performance
Most living beings perform most biological functions, whether physical, mental, or behavioral, in roughly 24-hour cycles. If you usually adhere to a routine, think of how you feel hungry, sleepy, or most energetic at certain fixed times every day. This is your circadian rhythm (CR), controlled by a group of nerve cells in your brain—the suprachiasmatic nucleus—and by external environmental factors like light and temperature.1 Following your circadian rhythm, your body has fixed times when it has optimum body temperature, blood pressure, hormone levels, and energy levels.
One study shows the majority of the components of sports performance like flexibility, muscle strength, and short-term high power output, vary with time of day in a sinusoidal manner and peak in the early evening close to the daily maximum in body temperature.2 Another maintains that diurnal variation of sports performance usually peaks in the late afternoon, coinciding with increased body temperature.3
Your core body temperature too shows a circadian rhythm, and as early as 1842, it was recorded that it peaks in the early evening and hits its minimum in the early morning with a difference of 0.9 °C.4 Research finds that it is dependent on your sleep-wake cycle—which again shows distinct CR—as sleep onset evokes a decrease of core body temperature5.
But the 0.9 °C gap can make all the difference. A study on rugby players showed that since the body temperature remains low in the morning due to a circadian low, this causes a low power output.6 The optimum body temperature can ease blood flow and enhance circulation to supply oxygen and other nutrients to the muscles, which boosts their endurance. Also, the joints release the synovial fluid that lubricates them and makes movement easier.
Even if you are an early bird and prefer a morning sprint, do a 15-minute warm-up to raise the temperature.
Common Times For Running
Mike Tyson used to run at 4am. But you could discount that as an exception. The common hours are early morning (6–7am), late afternoon (3pm–5pm), and evening (6–8pm). A 2014 statistics of 177 million runners across 30 countries show that on weekdays, 32 percent people run between 5 and 8 in the evening, as opposed to the 18 percent that run between 6 and 9 in the morning. On weekends, however, 8–11am is the peak time.7
Not many people prefer to run in the morning, but those who do cite several pros. Early morning ensures a cleaner and less-polluted environment. The roads are free from traffic and in the absence of a harsh sun, the run is enjoyable. Some people also report maximum energy in the morning, and they prefer kick-starting the day with exercise. A morning exercise also gives them plenty of time for muscle recovery.
Though the body temperature remains low during morning and it is commonly believed that people are most vulnerable to heart attacks and strokes in the morning8, a study proved otherwise. It showed a 10 percent drop in blood pressure during the day, 25 percent during night, and improvement in sleep in people who exercised at 7 in the morning. This was better than when the exercises were done in the evening. There was hardly any blood pressure or sleep improvement when exercise was done at 1 pm.9
But if you are not used to getting up early, you shouldn’t force yourself into a morning marathon. Your body’s circadian rhythm might remain sluggish due to disturbed sleep pattern, which would in turn affect your body temperature and blood pressure, making you vulnerable to injuries. Also, after almost 10 hours of fasting, the body usually remains low on energy. A mid-morning run, after a good warm-up and some light breakfast, might be a better option.
Science would suggest that late afternoon is the best time to run or for any kind of exercise. If you can space your lunch and your run judiciously, say by a couple of hours at least, a late afternoon run, 4pm onward, is the best time for you in terms of endurance, strength, and reaction time. This is because of optimum core body temperature and hormone levels. While both testosterone (T) and cortisol (C) levels are high in the morning, it is at this time that the ratio is optimum for performance, with less cortisol than testosterone, which aids in anabolism or destructive metabolism. So, if you are planning on weight loss, an afternoon run may be your best bet.10
At this time of the day, your muscles and joints are flexible, you have the energy to go for a long haul, and your lung function is at its peak.11
The cons of afternoon have nothing to do with your body. It could be the soaring temperature outside or it could be your inability to carve out an hour from your busy schedule. And while you need a break every now and then to clear your head, taking off into a completely different kind of physical activity might affect your task at hand. Mostly, it’s tough to get into the mood for a run in the middle of a busy day.
But if you do shake off the inertia and the excuses, make sure you are well-hydrated and get some warm-up before you get going.
Evening, too, is as good a time as afternoon. You have got the day’s work out of the way, your body is warmed up and the core temperature is at its best, and your energy levels are good enough to endure a sprint. A study on 600m and 1000m cyclists showed that the increased core temperature in the evening facilitates vasodilation and increased nerve conduction velocity. This ensures a better supply of nutrients and oxygen to the muscles and increased alertness and aids in substrate elimination. This in turn improves glycogenolysis and glycolysis to release more energy.12 An evening run is a good stress buster that leaves you perked up for other activities for the rest of the evening. It will even help you get a good, restful sleep. But if you find your energy levels are still too high to let you doze off, try pushing the run back by an hour.
The major deterrents to an evening run include high levels of pollutants in the environment, a rapidly cooling weather—adjusting to which might be difficult—safety concerns, vision problem, and traffic issues. You could avoid these by going on an early evening run. Any other excuse you come up with is probably just that—an excuse.
So, while you can conclude that running with a receding sun in the late afternoon is most effective, don’t switch jobs to make that happen. If you are comfortable with whatever hour you are running at, stick to that. It means your body has adjusted itself to that routine. But yes, it’s important that you fix an hour and don’t throw your body off kilter with runs at random times of day.
References [ + ]
|1.||↑||Circadian Rhythms Fact Sheet.|
|2.||↑||Atkinson, Greg, and Thomas Reilly. “Circadian variation in sports performance.” Sports medicine 21, no. 4 (1996): 292-312.|
|3.||↑||Hayes, Lawrence D., Gordon F. Bickerstaff, and Julien S. Baker. “Interactions of cortisol, testosterone, and resistance training: influence of circadian rhythms.” Chronobiology international 27, no. 4 (2010): 675-705.|
|4.||↑||Kräuchi, Kurt. “How is the circadian rhythm of core body temperature regulated?.” Clinical Autonomic Research 12, no. 3 (2002): 147-149.|
|5.||↑||Baker, Fiona C., Jonathan I. Waner, Elizabeth F. Vieira, Sheila R. Taylor, Helen S. Driver, and Duncan Mitchell. “Sleep and 24 hour body temperatures: a comparison in young men, naturally cycling women and women taking hormonal contraceptives.” The Journal of physiology 530, no. 3 (2001): 565-574.|
|6.||↑||West, Daniel J., Christian J. Cook, Martyn C. Beaven, and Liam P. Kilduff. “The influence of the time of day on core temperature and lower body power output in elite rugby union sevens players.” The Journal of Strength & Conditioning Research 28, no. 6 (2014): 1524-1528.|
|7.||↑||Reese, Robert James, Dan Fuehrer, and Christine Fennessy. What Time of Day Do People Run? Runner’s World. 26 August 2014. There are also enthusiasts who run during lunchtime and at night, but the number is comparatively less.|
|8.||↑||Morris, Christopher J., Jessica N. Yang, and Frank AJL Scheer. “The impact of the circadian timing system on cardiovascular and metabolic function.” Progress in brain research 199 (2012): 337.|
|9.||↑||Early morning exercise is best for reducing blood pressure and improving sleep. Appalachian State University.|
|10.||↑||Hloogeveen, A. R., and M. L. Zonderland. “Relationships between testosterone, cortisol and performance in professional cyclists.” International journal of sports medicine 17, no. 06 (1996): 423-428.|
|11.||↑||Medarov, Boris I., Valentin A. Pavlov, and Leonard Rossoff. “Diurnal variations in human pulmonary function.” Int J Clin Exp Med 1, no. 3 (2008): 267-273.|
|12.||↑||Fernandes, Alan Lins, João Paulo Lopes-Silva, Rômulo Bertuzzi, Dulce Elena Casarini, Danielle Yuri Arita, David John Bishop, and Adriano Eduardo Lima-Silva. “Effect of time of day on performance, hormonal and metabolic response during a 1000-M cycling time trial.” PloS one 9, no. 10 (2014): e109954.|