I used to run for 1hr 6 days a week and do 30-45mins weights. I got really bored of the hour running so a trainer at my gym suggested I cut it back to 30mins but add on a fitness class. So now I do a fitness class everyday..however I've found that if I run first I am tired in the class and if I do the class I am tired when running and don't run as fast as I could! Is it ok to maybe run for 15...fitness class then run for 15 after? I always do weights in the evening so could even maybe run for 10-fitness class run for 10...then a few hours break and do my final 10 before I do weights in the evening to make it up to 30minutes. Will it still be effective if I do short runs 3x a day or should I just stick it out and do 30mins at a time?