The ideal time to exercise is in the morning. However, a good time to exercise is whenever you can find time to do it, as long as it is not too close to mealtime time and preferably not when the sun is down. We all know that exercise helps prevent cognitive decline. So getting exercise in whenever you can is a good idea. But of course, do not over-do.
But try to avoid strenuous exercise at least one hour before and after meals. Strenuous exercise temporarily can open up the tight junctions in the gut causing increase intestinal permeability (also known as leaky gut). While not a often a problem for the healthy, for those with autoimmune conditions, this may mean that undigested food particle molecules can leak into the bloodstream triggering an immune reaction. [reference]
Best to not exercise when sun is down. Exercising in the evening when the sun is down often means exercising too close to bedtime. And for some, this can be too simulating, causing difficulty sleeping. Exercise also causes production of cortisol. Afterall, it is a bit of a stressor. High cortisol at night can also make it difficult to sleep.
The natural cycle of cortisol is high in the morning and low at night. And we should honor that. Since cortisol is already high in the morning, it is an good time for exercise. But not too early in the cold right out of bed. Give you body a little time to warm up. You don’t want do exercise with tight muscles and stiff joints. Do some light warm ups first.
Exercise during the day also help support our circadian rhythm. We are not nocturnal animals. We are meant to be active during the day and not at night.
Article on Greatest.com writes…
“one study showed that working out at 7 a.m. (compared to 1 p.m. or 7 p.m.) may help people sleep more soundly at night.”
and that afternoon workout have the advantage of …
“the body produces more testosterone during late afternoon resistance training than it does during morning workouts”
“people can burn up to 20 percent more body fat exercising on an empty stomach”
So if one of your aims is to loose weight, exercising on an empty stomach is much easier to do after waking up and before breakfast.
Some people find better motivation when exercise is in the morning because in the evening people are drained from the day and don’t have the energy to exercise.