Sleeping on Your Left Side: Health Benefits Backed by Research and the Wisdom of the Rambam

A good night’s sleep, free from discomfort or interruptions, is well-known to benefit both our physical and emotional health. In a series of international studies, researchers examined whether the position in which we sleep has any impact on the quality of our sleep. The findings were surprising: almost unanimously, experts concluded that sleeping on the left side throughout the night is the most beneficial position — helping protect the back and neck and reducing the risk of sleep apnea.

According to the researchers, sleeping on the left side is recommended for everyone. Even when simply lying down rather than sleeping, they advise choosing the left side. They claim that sleeping on the right side may contribute to a variety of health problems, including digestive issues, irreversible back damage, breathing difficulties, and even asthma that may develop as a result of prolonged right-side sleeping.

By contrast, sleeping on the left side offers many important health advantages, which the researchers listed as follows:

1. Improves digestion and prevents excess stomach acid from rising into the esophagus, thereby reducing heartburn.

2. Supports efficient blood flow from and back to the heart.

3. Aids in the body’s natural detoxification processes through the digestive and urinary systems.

4. Promotes the drainage of fluids into the bloodstream by allowing them to move naturally toward the spleen and other essential organs of the lymphatic system.

5. Helps maintain the health and stability of the spine.

6. During pregnancy, left-side sleeping encourages better blood circulation, benefiting both mother and baby.

(Photo: shutterstock)

The Torah perspective

In Rambam’s Hilchot De’ot, within the chapters on health (chapter 4), it is written: “A person should not sleep on his face or on his back, but on his side. At the beginning of the night — on the left side; and toward the end of the night — on the right side.”

According to the great Jewish physician and scholar Rabbi Moshe ben Maimon (Maimonides), the reason is connected to the stages of digestion in the body. Digestion occurs in three phases — in the stomach (through digestive juices), in the liver, and then throughout the organs of the body. At the beginning of sleep, it is best to lie on the left side, as this supports the digestive process in the stomach. Later in the night, the liver — located on the right side of the body, benefits when we switch to the right side, which further assists digestion at that stage.