If you're exercising to the point that you're out of breath, you're doing yourself a huge favor. They've increased the amount of cardio we should be getting each week, and this number alone is enough to knock the wind out of you.
More than a third of people will cut a workout short if they forgot something. Others will quit early because they ate a waffle first and shouldn't have. It turns out, there are a whole host of reasons for not finishing strong at the gym.