Elderly people, especially those who are frail, are at a greater risk of lung damage from respiratory infections. Most do not breathe very deeply. Rather, they take shallow breaths and tend to breathe through their mouths. In addition, many sit for long periods in positions that further impair movement of air in and out of their lungs.

My friend Dr. Gerald Lemole is an expert on the lymphatic circulatory system, a frequently ignored part of the body’s circulation. The lymphatics are thin-walled vessels that remove harmful compounds that accumulate outside our cells. These harmful compounds are composed of dangerous metabolic products, cell fragments, fragments of dead bacteria, viruses, and mycoplasma — all of which, if not removed, will eventually poison cells, tissues, and organs.

The lymphatic system is not connected directly to the heart, and therefore depends on the contraction of muscles to move lymph fluid through these vessels. One of the major benefits of regular exercise is that it keeps this fluid moving, thus helping remove dangerous compounds from the body.

The lymphatics are also connected to our lymph nodes, which contain an assortment of immune cells called macrophages and neutrophils that further clean tissue fluids.

Unfortunately, if people become “couch potatoes,” their weak muscles cannot keep lymph flowing. As a result, toxins accumulate in tissues and organs, making them sick, weak, and progressively frail. It also makes them much more likely to suffer from an infection.

Dr. Lemole emphasizes that lymphatics also play a critical role in the health of organs — especially the lungs and the heart. His book, “Lymph & Longevity: The Untapped Secret to Health,” explains the lymphatic system in an easy-to-understand manner that includes advice about foods that benefit lymphatic flow, as well as special exercises to improve lymph circulation.

In this book, Dr. Lemole also explains that deep breathing is the most effective way to improve lymphatic circulation in the lungs and heart. He advises that people take at least 10 deep breaths every 30 minutes. Furthermore, Dr. Lemole describes studies that show lymphatic draining of inflammatory fats from the walls of arteries plays a major role in preventing atherosclerosis (hardening of the arteries).

Enhancement of lymphatic flow in the heart and lungs may be another mechanism by which vigorous exercise helps prevent heart disease. Physical effort makes us take deep breaths until we once again regain our proper oxygen saturation.