 Working out too much can actually be bad for your health. If you're working out strictly for health benefits, two and a half to three hours a week will do. When you get to over five hours a week of moderate to vigorous exercise, you may enter the realm of performance training, which requires recovery time and not recovering properly can lead to overtraining syndrome, which causes symptoms like trouble sleeping, chronic fatigue, decreased immunity, injuries, and even weight gain. Overtraining can also lead to loss of motivation and could be the reason your regular workout feels more challenging, which could explain why you never use that new gym membership.