The problem of setting the training at a certain moment in the day is more serious than it appears to be. The choice of the period when we train depends on more factors.
More exactly, people should train when their stomach is empty, but the level of glycemia must be constant. Considering a normal awake – asleep rhythm, there are two favorable moments when we can set fitness programs and training in general: one in the morning, between 10-12, and the other one in the afternoon, between 16-19.
Current practice in most of the sports confirms these periods as best for training.
Another argument for choosing one of these intervals for training is the body temperature, which now gets to its maximum. The second period (16-19) is even better than the first one from this point of view, because the temperature is higher and this enhances sport performance.
It is not advisable to train very early in the morning, right after waking up and before breakfast. However, there are authors who support the idea of having the training in this period. The reserves of glycogen are limited after the lack of food during sleeping and this is a reason for using the adipose tissue earlier in training than in other cases.
Unfortunately, at the same time, the stress hormones (cortisone) are secreted abundantly, so besides the adipose tissue, there is the risk of losing precious muscular tissue.
Another argument against this is the fact that body temperature is very low in the hours of morning, so no motion parameters (force, resistance, speed, mobility, skill) can be fully activated. Thus, a prolonged and tiring warming up would be necessary, hindering the actual training.
Everybody agrees that training before bedtime is not advisable at all, because they delay sleep a few hours, given growth of cortical activity and of body temperature.
This schedule can be adapted to any biorhythm and time zone and once automatism installed, effectiveness of training will definitely increase.