First of all, every pregnancy is different and unique. Some are vomiting all the time during the first trimester (or the whole pregnancy), others feel just great during all these nine months. I’ve read a blog telling the experience of running a half marathon (ca. 21 km) being 7 months pregnant and know a couple of stories when they had to stay in bed almost the whole period of pregnancy. Everybody is different and not every advice will help in your case.