Some time ago I received an answer to the following question in the link: Present perfect progressive I have been doing
This question was about finding ways which grammar construction to use in Spanish for sentence in English "I have been doing something". In English this construction is used to express actions that began in the past, but are still continuing in the present. In the link above all grammar constructions in Spanish that are used require period of time to be specified (can be even vague, such as "for some time" - Llevo tiempo estudiando para aprender el idioma).
But what would be the best way in Spanish to say below?
I have been running to lose weight
In this case the meaning is that I was doing this and still continue doing it, AND at the same time period is not specified.
I bumped into the following structure when red the translation of lyrics of a song from English to Spanish (song is ATB - Let U Go):
I have been running like a sentence never begun - Estuve corriendo como una sentencia que nunca empezó
I never used construction "estuve + gerundio" and don't know if it is used frequently.
So, 2 questions: 1) How would you translate "I have been running to lose weight"? Please note, that we, of course, can say "I run to lose weight" or something similar, but I am asking about precisely construction "I have been -ing without time period specified" 2) In any case, what would be the difference in meaning between these 2 constructions mentioned?
He estado corriendo para perder un peso
Estuve corriendo que perder un peso
Also, which version would you use in daily life (if you had to say this exact English sentence in Spanish)? Maybe there are other constructions that can be used?
P.S. I would not use "Estaba corriendo", because it would mean "I was running", which means technically that I was running when something else happened AND the action is not continued anymore (I am not running anymore).