I just started morning cardio again and my HR is at about 110-120 BPS for about 20 minutes then it climbs to about 130 BPS until I am done at the 45 minute mark. Should I get the HR up faster then stick it there for a while or let it get there on its own. I am trying not to use any muscle activity at all when doing the cardio. In the past I tend to go overborad and end up losing muscle so I thjought I would take it slower this time around. I am 31 years old.