I've heard this type of experience referred to as a "flow state". Wikipedia lists some typical characteristics of flow:
- High challenge, high skill level
- Concentration and focus
- Loss of self-awareness
- Time becomes irrelevant
- You are in control
- Intrinsically rewarding activity (and so can be perceived as "addictive")
- You forget to eat and sleep
Playing is an interesting word to be used for both music and sport, isn't it, because small children when engaged in play can appear to be in a very similar sort of state to what we call a flow state. Playing is the major way that kids learn new skills, and it seems to be also that the play they are drawn to reflects whatever skill they need to work on at the time.
I think that the ability to enter the flow state, whichever activity we choose as a way in, is necessary for us all. It quietens the endless low-level chatter of the conscious mind. All very well, but why might this predict success in other areas of life? Perhaps because the sort of person who achieves a flow state has the sort of personality to stick at something, practising over and over until they achieve a high skill level. Or perhaps it's also that the flow state itself brings direct benefits, similar to those brought about by meditation, such as reduction in anxiety and stress, as well as a reduction in blood pressure and improvement in vascular health. Or perhaps the suppression of the chatter actually helps important ideas "rise out" of the subconscious and stimulates creative problem-solving and lateral thinking.
So there you are. Playing - whether creative pursuits, sport or music - could be good for your mental and physical health and maybe even help you achieve in other areas of your life too. Especially if you practice, get really good at it, and keep challenging yourself.