What is better, morning or evening exercise?

For most people daily exercise is dictated by when they can fit it in during their busy schedules. We all know that physical activity has many health benefits and doing the recommended minimum has a better outcome than being inactive. Some people are adamant that morning sweat is the best way to start their days while other cannot imagine breaking a sweat before noon.

So what is the optimal time to workout - A.M or P.M?

For the high performance athlete the time of day you chose to train might make a difference. A recent study comparing morning and evening training concluded that maximal oxygen uptake, anaerobic capacity and oxygen uptake kinetics were higher in the evening than in the morning allowing for longer performance.

Researchers have also found that body temperatures are higher in the afternoon than in the morning. In a study done on competitive swimmers looking at the difference between morning and afternoon warm ups, concluded swimmers had to warm up longer in the morning in order to raise their body temperature to match those of the afternoon. Even with equal body temperatures after a long warm up, the swimmers performed better in the afternoon as compared to the morning.

People who exercise in the morning are more likely to keep up with an exercise routine and minimize scheduling conflicts. There is also evidence to suggest that working out in the morning improves quality of sleep and reduces blood pressure as presented by a study done at Appalachian State University.

When to exercise:

• When you can fit into your schedule – Adults 18-64 years should focus on moderate to vigorous aerobic activity for at least 150 minutes a week in bouts of 10 minutes or more. Add resistance training at least twice a week. 
• Anaerobic and speed workouts – To get the best results at such intensities the afternoon might be the ideal time. 
• When weather permits – When exercising outside, be aware of the weather. In hot and humid days avoid mid-day workouts. In the winter be wary of the wind-chill factor. 
• Competitions - For those competing at a specific time of day, working out at the assigned competition time might be wise for adaptation. 

Overall, the best time to exercise is one that works best for your schedule and also allows you to be consistent with your workout routine.

References from the SIRC Collection:

1. Aldemir H, Atkinson G, Cable T, Edwards B, Waterhouse J, Reilly T. A COMPARISON OF THE IMMEDIATE EFFECTS OF MODERATE EXERCISE IN THE EARLY MORNING AND LATE AFTERNOON ON CORE TEMPERATURE AND CUTANEOUS THERMOREGULATORY MECHANISMS. Chronobiology International: The Journal Of Biological & Medical Rhythm Research. March 2000;17(2):197.

2. Brisswalter J, Bieuzen F, Giacomoni M, Tricot V, Falgairette G. Morning-to-Evening Differences in Oxygen Uptake Kinetics in Short-Duration Cycling Exercise. Chronobiology International: The Journal Of Biological & Medical Rhythm Research. May 2007;24(3):495-506.

 3. Hill D. Morning-evening differences in response to exhaustive severe-intensity exercise. Applied Physiology, Nutrition & Metabolism. February 2014;39(2):248-254.

 4. Racinais S. Different effects of heat exposure upon exercise performance in the morning and afternoon. Scandinavian Journal Of Medicine & Science In Sports. October 3, 2010;20:80-89.

 5. Rowland T, Unnithan V, Barker P, Lindley M, Roche D, Garrard M. Time-of-Day Effect on Cardiac Responses to Progressive Exercise. Chronobiology International: The Journal Of Biological & Medical Rhythm Research. August 2011;28(7):611-616.

 6. Schaal S, Peter M, Randler C. MORNINGNESS-EVENINGNESS AND PHYSICAL ACTIVITY IN ADOLESCENTS. International Journal Of Sport & Exercise Psychology. June 2010;8(2):147-159.