hi,just a quick questiona.i'm a 17 yeas old teenager,healthy,used to exercice 5 days a week 1 hour each day at home(cardio workout) but recently i've joined a local gym and i've been hitting the weights plus cardio for only 3 times a week,i don't have any health issues,but my problem is that sometimes i suffer from low sperm count and like many days pass i don't get an erection and if i do it lasts for like only a minute and goes away.what could be causing that and thanks:)