It has been proven, time and time again, that being generally fit is great for your health! For example, this study shows that improved fitness can increase longevity, decrease risk of coronary heart disease, cardiovascular disease, stroke, and colon cancer. It even shows that simple activity, not just fitness, can produce these benefits. One must be careful, however, when pregnancy comes into play. It's easy to want to be careful not to overexert yourself, but that doesn't mean to be completely sedentary! This study shows that exercise during pregnancy improved aerobic fitness, muscular strength, created a healthier postpartum, fewer cesarian deliveries, and good delivery outcomes. However, don't work out too much toward the beginning of your pregnancy - take it easy and slowly - because complications can occur. This study, for example, shows that too much physical activity in early pregnancy can negatively affect placental growth and function. It's great to work out when you're pregnant, but be sure to go over your fitness regimen carefully with your doctor. Too much and too little can both be dangerous!