Unfortunately there is no one-size-fits-all answer of when you should have your workout.  In fact, according to the Living Research Institute, the answer to this age-old question (and reason for the on-going debate) is because the best time to workout really depends on your personality. While it is possible to retrain your body’s natural circadian rhythm, or internal clock, because of life obligations such as work, school or family, the ideal routine should, if possible, fit with your own internal clock. This will allow you to shape your workouts around your personality and not the other way around, resulting in a consistent schedule that you are more likely to stick to long term.

Since there are pros and cons to both, below is a list that compares the two most popular times to workout—early morning and early evening. Take a look and see which one will get you going:

A.M. Workout

• 90% of those who exercise consistently have a morning fitness routine – YAHOO’s Healthy Living
• Co-authors Tom Rath and Jim Harter found that those who workout in the morning have a higher level of well-being “in the social, career, financial, physical, and community elements of life.” – Wellbeing: The Five Essential Elements
• Studies show that a 20 minute workout produces endorphins to boost your mood for hours afterward, leading to a more positive outlook and productive work day – USNews.com
• You have more energy throughout the day, so you won’t be as likely to reach for that caffeinated, simple carb, or high trans-fat snack during the usual afternoon slump – YAHOO’s Healthy Living
• Research shows that strenuous exercise within two hours of sleep can hurt your ability to fall asleep – Living Research Institute
• “People that exercise in the morning are more likely to make it a habit, as there’s less chance of scheduling conflicts that get in the way of exercise.” —Julia Valentour, Exercise Physiologist and Program Coordinator at the American Council on Exercise
• Morning exercise “jump starts” the metabolism, helping to burn more calories during the day – Living Research Institute
• “Exercise improves brain functioning and our ability to concentrate; doing it in the mornings helps to prepare us for a busy day at work” – healthguidance.org
• With getting ready for work being a priority, you may have to work out within fixed time limits, and cannot exercise as long as you might want – Wellbeing: The Five Essential Elements
• Showering directly after morning workouts can leads to better hygiene and clearer skin – Cynthia Bailey, M.D, Dermatologist
• Gyms are often most crowded in the evenings, so you may not get the machine you want – Living Research Institute

P.M. Workout

• “If you’re not a morning person, it’s going to make it that much harder to get out and exercise, it’s going to be that much easier to put it off” – Julia Valentour, Exercise Physiologist and Program Coordinator at the American Council on Exercise
• Studies show that the most productive workouts occur when body temperature is highest, which is usually in late afternoon – American Council on Exercise
• There are endless studies of the health benefits of meditation; easing into your busy day with meditation and ending with a workout can be a great way to combat stress and feel balanced
• “In the mornings our energy levels are less than optimal, and our muscles are still stiff from sleep, which can lead to an increased risk of injuries” – Living Research Institute.
• Working out later in the day provides an often-needed break in one’s work day and clears the mind so that the body can transition and relax more easily for quality time with family – Living Research Institute
• With dinner and family obligations, you may have to work out within fixed time limits, and cannot exercise as long as we might want – Wellbeing: The Five Essential Elements
• You may not be able to shower right after, which could lead to hygiene concerns or breakouts – Cynthia Bailey, M.D, Dermatologist
• Studies on lung function, temperature, hormone levels, and body rhythms suggest that these factors are most conducive to exercise in the afternoon or early evening (around 6pm) – Living Research Institute.
• If you are constantly working to improve your athletic performance to reach a goal, afternoons are best for muscle strength
• “Afternoon or early-evening exercise tends to lower your appetite, and reduce the amount of food you feel like eating for dinner” – Living Research Institute.
• Exercising in the evening, as long as it’s not too close to the time you go to bed, can make it easier to fall asleep, plus lead to deeper, more restful sleep for some people – Today Show

At the end of the day (no pun intended), there are pros and cons to both. What matter most is that you make a goal and stay consistent with your routine in order to reap long-term benefits.  Weight Loss Expert, Denise Hall-Carter explains, “Remember, regardless of whether you choose to workout morning or at night, make sure you add it to your schedule so it’s like a conference call with your boss; the most important thing is showing up!”  Still not sure which is the best for you? Give both a try! Try working out in the mornings on Mondays, Wednesdays and Fridays and working out in the evenings on Tuesdays and Thursdays for 3 weeks. This will allow your body to get in the habit of both and notice which feels most natural. Keep a journal of how you feel before and after each workout and throughout the day. See what clicks and, more important, which routine you actually stick to. We all go through our motivational-ups and fatigued-downs in the workout world, so the routine that allows you to be as consistent as possible is likely your best bet.