Just like we are anatomically designed to breathe through our nose, the design of our bodies favours us to lie on our left when resting and sleeping. Here are some reasons why.
There are two lung lobes on your left side and three on the right. When you are lying on your left side, the two lobes will be slightly compressed with less air exchanged. When you rest, less CO2 is produced and respiration reduces. The three right lung lobes are then on the upper side and can effectively breathe for you satisfying all requirements. If you are sleeping on your right hand side, three lobes are compressed and there is a chance your breathing volume will increase if the two left lobes can’t effectively satisfy air exchange requirements.
The aorta exits the heart on the left hand side. Resting on the left side means that your heart works with gravity to pump the blood to the lower part of the body. Resting on the right side means the heart has to pump blood uphill and naturally this places a greater strain on the heart.
The stomach is shaped and aligned so that when you rest on your left hand side, the gastric juices are contained within and the stomach can churn effectively, releasing its contents slowly into the small intestine. Sleeping on the right hand side can make it easier for gastric juices to flow upwards potentially creating heart burn.
The lymphatic system is responsible for removal of toxins and all other waste products. In order to work it needs physical movement. At night when you are immobile the lymphatic system is largely stagnant. However, sleeping on the left hand side means gravity will aid in lymphatic flow towards the spleen – a major lymphatic organ.