The way you sleep can affect how well and how long you sleep as certain sleeping positions might make you more likely to have bad dreams, according to Tom’s Guide. A study found that people who sleep on their left side may have more nightmares compared to those who sleep on their right side because sleeping on your left side puts more stress on the heart. What is more, sleeping on your back may also lead to more nightmares. Breathing issues like sleep apnea, which can be worse when sleeping on the back, might be a reason for bad dreams. “People who experience nocturnal breathing issues are mor…