Is It Better To Run In The Morning?
The morning versus evening run debate, which is as old as recreational running itself, is compelling on both sides of the argument. On one hand, no one can deny that extra sleep is important. On the other hand, there is no better feeling than knowing the hardest part of your day is complete. From a scientific perspective there are plenty of reasons why running first thing in the morning is both a great idea and a bad one. Discussed here is how the body differs physiologically in the morning versus other times of the day, the advantages and disadvantages of a morning running habit, and how to minimize associated risks.
Understanding Circadian Rhythms
Our bodies are controlled throughout the day by circadian rhythms1, which are physiological responses set on a 24-hour cycle that fluctuate based on time of day. Body temperature is one example, as it is lowest first thing in the morning and highest in the evening. Even a slight discrepancy in core body temperature can affect the relative feeling of fluidity in a runner’s muscles, which can drastically change the effort put forth on a run.
A second factor is lung function, which is also controlled via circadian rhythms. For people with asthma2 or other pulmonary disorders, early morning exercise may have a detrimental effect on symptoms such as coughing or wheezing. Other studies3 indicate pulmonary function is highest between 8:00 a.m. and 9:00 a.m. and lowest during lunch time. Finally, there are also implications on metabolism4 when running first thing in the morning.
When we disrupt the routines that our bodies find most comfortable (i.e. diurnal animals eating during the day and nocturnal animals eating at night) metabolic malfunction can occur, which is especially relevant for athletes who wake up prior to 5:00 a.m. to run on an empty stomach.
Benefits of Early Morning Running
• Mental Toughness
Exercising when our bodies are working against us is difficult, but it is also a great way to build mental toughness. Dragging ourselves away from our cozy beds in favor of braving the elements on a chilly morning teaches our bodies to perform no matter the conditions, and makes an 8:00 a.m. race feel like sleeping in.
• Jumpstart your Metabolism
Running on an empty stomach can increase the body’s metabolism, which is why early morning running is often recommended to athletes who are trying to lose weight. However, the metabolic boost also makes you feel hungrier after the run and for the hours following, which can lead to cravings and overeating later in the day.
• Cleaner Air
Running in the morning has the added advantage of cleaner air, thanks to fewer emissions from cars before the morning and evening commutes. For runners who suffer from asthma or other disorders where air quality is important, running when there are fewer toxins in the air can be beneficial.
• More Time During the Day / More Productivity
When you do your workouts in the morning you will reach peak performances during the day. It’s widely known that many CEOs, leaders and productivity experts exercise early in the morning. If you’re really busy and don’t know how to implement running in your over-saturated schedule, read this blogpost I wrote some time ago.
Disadvantages of Early Morning Running
• Increased Injury Risk
Besides having a cooler body temperature first thing in the morning, muscles and joints are more stiff, blood circulation is poor, and dehydration is likely. These factors all contribute to increased injury risk for morning runners, especially for those who are prone to tendonitis or muscle strains.
• Increased Relative Exertion
Simply put, running in the morning is going to feel a lot more difficult than running at lunch or in the evening. For people who colloquially “embrace the suck” this phenomenon is no big deal, but for athletes who are returning to running after a long break, are attempting workouts at prescribed paces, or simply do not like running much to begin with, it may be best to occasionally switch things up by running in the evening when relative exertion is lowest.
• Heart Attack and Stroke More Likely
Scientists have found that the risk of heart attack and stroke5 are more likely first thing in the morning. Thanks to the cycles of our circadian rhythms, the stress hormone, cortisol, is highest within the first 3 hours of awakening (this hormone can affect blood pressure), as is adrenaline, which affects both heart rate and blood pressure.
Additionally, blood is more likely to clot in the morning, and the process that the body undergoes to break up a clot, fibrinolysis, is hindered in the early hours of the day. While athletes – particularly runners – are far less likely to suffer either a heart attack or stroke relative the general population, those who are at risk may want to rethink their morning ritual.
• Improper Fueling
For morning runners, eating breakfast beforehand is rarely a priority. However, after an8 –12 hour fast, muscular glycogen stores are at their lowest which affects the body’s ability to recruit energy, leaving legs feel heavy or tired.
Tips for Morning Running
• Warm Up
Do not expect to begin running and immediately feel good from the get-go. A dynamic warm up is especially important first thing in the morning in order to raise the core body temperature, increase flexibility, and improve circulation. When lung function is low, a short warm up can also help open airways and improve respiration. In the warmer months, complete a warm up by going for a short jog followed by leg swings and skipping drills. If the weather is cold outside, opt to warm up your body and lungs indoors by performing leg swings, jumping jacks, or pushups inside. A proper warm up should be 7–10 minutes long.
• Focus on Effort instead of Pace
When running in the morning, the effort you normally put forth for 10:00 pace might produce an 11:00 mile instead. Resist the urge to beat yourself up over this discrepancy and instead plan to run your workouts based on effort instead of pace. For instance, on easy days simply run a pace for which you could easily hold a conversation if talking in short sentences.
On tempo days, aim for marathon effort. During intervals that are 800 m or below aim for 5k – 10k effort, while for longer speed sessions, half marathon – marathon effort may be more appropriate. A second strategy is to incorporate more hill work into your routine in order to avoid ascribed paces for your runs.
• Eat Breakfast
The top two reasons that runners avoid eating breakfast before running are lack of time and fear of suffering from gastrointestinal distress. However, putting carbohydrates into your body before you run is important, especially if you are running at least 6 miles or have a hard workout planned. If solid food does not sit well in your stomach consider alternatives such as baby food, energy gels or chews, or a carbohydrate-laden sports drink.
Running first thing in the morning will leave you energized for the entire day and boost your metabolism. On top of this, running first thing in the morning is more peaceful and quieter, with less annoyances, traffic and things that could disturb you. It’s generally cooler in the morning, thus less inflammation. Most races also take place in the morning, so if you’re training for such a race, your body and mind will be used to running at that time of the day.
1. Christina M. Spengler and Steven A. Shea “Endogenous Circadian Rhythm of Pulmonary Function in Healthy Humans”, American Journal of Respiratory and Critical Care Medicine, Vol. 162, No. 3 (2000), pp. 1038-1046. doi: 10.1164/ajrccm.162.3.9911107 Link
2. Richard J. Martin “Nocturnal Asthma: Circadian Rhythms and Therapeutic Interventions”, American Review of Respiratory Disease, Vol. 147, Supplement: Airway Diseases Update June 1993 (1993), pp. S25-S28.doi:10.1164/ajrccm/147.6_Pt_2.S25 Link
3. Medarov BI, Pavlov VA, Rossoff L. Diurnal Variations in Human Pulmonary Function. International Journal of Clinical and Experimental Medicine. 2008;1(3):267-273. Link
4. Eckel-Mahan K, Sassone-Corsi P. Metabolism and the Circadian Clock Converge. Physiological Reviews. 2013;93(1):107-135. doi:10.1152/physrev.00016.2012. Link
5. Shaw E, Tofler GH. Circadian rhythm and cardiovascular disease. Curr Atheroscler Rep. 2009;11(4):289–295. Link