I do all of my exercising (running, cycling, swimming) in the evening, after work. Several people have told me that I should be exercising in the morning. They say you get more benefit from the workout in the morning, I’m cheating myself by working out at night. One person even went so far as to say I might as well not exercise at all. I don’t see why it matters. After all, you’re doing the same amount of work. So, does it make any difference, or is it a myth?
IANAExercise physiologist.
IMO, they don’t know what they are talking about. Exercise is always good. It burns calories and raises your metabolism.
If you work out in the morning before eating, you are raising your metabolism at the time of day when it already raised, and using calories when you are already low on available calories. This can get stored fat to be converted to calories. Frankly, I would get sick if I did this, not to mention that I would never exercise if I only did it in the morning.
If you work out in the evenings, you are using calories and raising your metabolism when you have the most calories available (if you are like most people and have your heavy meal at suppertime) This means that you are going to use the calories before they get stored, and raise your metabolism when it is going to be at it’s lowest point. Some people find it hard to sleep when they exercise late in the evening, I find it helps me sleep better.
One of the recommendations for losing weight is to get the majority of your calories earlier in the day, when they can be burned off rather than stored. In my totally unsupported opinion, this implies that the later you can burn calories in the day, the more weight you will lose as well. But I prefer to exercise in the evening, so I might be prejudiced. 
As far as exercising in the evening being no better than not exercising at all? I don’t think so
The most important thing is to exercise, period. Do it when it works for you and ignore people who try to tell you that that is the wrong way to do things.
Precisely.
We could talk about ideals in terms of your metabolism, burning fat vs. muscle, etc. But the reality is this: a lot of us have busy schedules or personal preferences to when we start/end our days. We may not always be able to haul our butts out of bed at 5 a.m. to exercise, or we may find millions of excuses why we can’t stop at the gym on the way home.
If you find an exercise routine that fits into your lifestyle and pleases you, you’re more likely to stick with it. Getting up at 5 to jump start your metabolism 1 day, followed by 4 more days of battling with the snooze button is far less effective (physically AND mentally) than actually making it out there and exercising 4-5 days on the way home from work.
There are so many of us in this world who don’t do exercise of any sort, that it seems we should be thankful that there are those who try and attempt an active lifestyle. And perhaps even support that effort, rather than throwing out holier-than-thou advice on how it’s not the “best way to do things.”
Harumph. If it feels good, do it.
Yes, exercise whenever you can, but there’s a reason that morning exercise is better for some people.
My personal trainer recommended I work out in the mornings because I tend to eat large portions of food throughout the day. If I eat before I work out, I will eat until my stomach sticks out of my pants.
If I eat after I work out, I control myself because I feel good (thinner and more in shape) and have enough endorphins in my system to seriously watch what I eat. I also don’t get hungry during the day because it feels like my body is still “working”.
If you notice yourself eating too much during the day, try working out one morning to see if you eat less. Works for me anyway.
Don’t get me wrong, I’m not planning on changing my exercise routine. I am not a morning person, I don’t get up at 5 am for anything. 
I was just wondering if there’s any physiological reason that working out at one particular time is better than another. If it helps, I don’t need to lose weight, I exercise to improve performance. I run 5k-10k races, and an occasional triathlon.