Endorphine, a morphine-like substance that works in the brain, this substance has a calming and diminishing gloomy feelings. This substance is produced in an expanded manner, especially with a calm endurance load (running). Every runner knows the feeling after running. Tired but satisfied.
Adrenaline, this is the substance that “shoots” through us in the event of a shock, stress or excitement. This can be a pleasant feeling if the sensation is desired (rock climbing), but undesirable in, for example, an exam. Relaxed exercise reduces the production of adrenaline, so exercising reduces anxiety. A desirable increase in dangerous sports. The adrenaline makes us more alert. Every substance has its positive and negative effects.
Testosterone, the male hormone, present in men in high concentration, in women in low concentration. Exercise has a positive influence on the production of this substance. An increased concentration gives a good feeling. Serotonin, is a substance that gives negative feelings with an increase in dosage. It is known that with extreme efforts the dosage increases and can therefore give negative feelings, a kind of brain fatigue. With lighter efforts, this brain fatigue probably also occurs, but then gives a feeling of relaxation.