Exercise is a natural high for some people, while others feel like they have to drag themselves through it. Dopamine plays a key role in all of this. It is a chemical, which can be released following exercise and is associated with increased feelings of motivation, pleasure and wellbeing. Unfortunately, it seems that some may not receive this chemical because of genes that interfere with its release.
A study on 3000 adults, found that the motivation to exercise may be hard-wired. An inherited gene may cause you to seek out physical activity or choose a more sedentary lifestyle. This gene provides a good explanation on why some people just experience that high from exercise. An important note however, is that nothing is set in stone and anyone can change. According to the researchers, although this research presents a challenge for some people, anyone can rewrite their brain so that exercise becomes pleasurable and rewarding.
Key to this, is to find a space that you find comfortable and you can relax and enjoy the experience of exercise.
Dishman, Peterson, Arud (American Physiological Society meeting) 3/11/2016