For me, this is related to the anxiety and excitement that betting causes; mixing coffee, energy drinks, or other drugs will only intensify the effect of these sensations. Personally, I have a set schedule for my activities; I rarely spend more than two hours betting. Using the example given for a sports bet, I simply place the bet and wait for the result; following the game won't make it go my way. Of course, I enjoy watching the matches and bet more on the local championship; I don't have to force myself to stay up late at night, for example.
Yes, it's directly related to anxiety and excitement levels. Similar effects can be experienced when you are triggered by a videogame, especially when there are grinding mechanisms involved. Achievements or rewards are directly connected to feeling pleasure. The more rewards we get, more pleasure we feel, through dopamine being released in our brains.
Drugs can enhance that effect, but aren't necessary. Even without drinking or using other drugs, we can still feel triggered by gambling in high proportions, leading as consequence to lack of sleep and increasement of brain activity.