Researches show that carbohydrate intake during exercise blocks the production of growth hormone whose secretion is particularly active during workout process. Peak hormone emission is being phased out within 60 minutes of active exercise (one of the reasons, by the way, why is not recommended to train for a longer period of time).
However, this is a very narrow view of the human hormonal balance. Specialists studied a variety of sources and literature regarding the necessity of reception of carbohydrates during training. Most of studies show that the intake have certain benefits and the information that carbohydrates block the hormone is erroneous. The truth is that somatotropin itself is a weak anabolic and is not directly involved in muscle building process.
Much more important in these sense are various growth factors and other hormones. For example, the secretion of IGF-1 is associated with the release of insulin, for which, by the way, we require carbohydrates. In addition, energy will allow us to spend a lot more intense workout and prevent muscle catabolism, which is much more important than some portion of somatotropin. Besides, this hormone is released during the night, and the body does not remain deprived of it. However, if there is a goal to increase growth hormone in the blood, it is known that hypoglycemia (decrease in blood sugar) promotes the release of this hormone. In this case it is enough to enter into the daily schedule small aerobic exercise (exercise bike, jogging) up to 30 minutes a day, which represent another good incentive to increase levels of the hormone.