Ask any body builder and everyone will say they will feel light headed, nauseous and even sometimes even puke when they train big muscle groups with exercises such as squats and dead lifts. Some great bodybuilders even take pride that they puke after an intensive bout of weightlifting as an indication that they have had a fantastic workout. But to many, these symptoms are unpleasant, disruptive and could be even be dangerous and cause injuries. Perhaps, you may also have experienced these symptoms as well. What happened? Well, there could be several causes. • First of all, you may have eaten or drunk too much before your gym workout. So you blood is channeled to your digestive organs for your digestive process. But when you begin to exercise intensively especially on big muscle groups, a lot of blood is channeled away from your digestive organs to the muscles. When that happens, food is now in your digestive system left unattended and therefore undigested and thus causing you to feel nauseous. • Your blood sugar level may be low. This could happen when you are on a low carbohydrate caloric restriction diet or have not eaten for sometime and is now lifting heavy weights. You will feel giddy, tired and may even develop a headache and suffering muscular weakness. It simply boils down to a decreased of energy level for not having enough energy nutrients prior to your workout. • The most common cause of nausea when weight lifting is low blood pressure. It could be inherent that you have low blood pressure and if not, it is caused by change of body position. Have you ever felt giddy when you are sitting stationary for sometime then suddenly gotten up and stretch? Well, if you have had that experience, then the same logic and science applies. The sudden fall of blood pressure happens when you are in a squatting position and then suddenly bursting upwards to a standing position with the blood pooled in your lower body and not sending the blood fast enough to your upper body and your brain. These are some of the reasons why many of us will experience giddiness, nausea and even puke when we do exercises like squats and dead lifts with heavy weights and when working on big muscle groups. Now that we know the reasons, we can avoid these unpleasant symptoms by taking necessary precautions during our gym workout on heavy weight days.