Age-related Physiologic Changes

Over time, the body gradually goes through normal age-related physiologic changes. As the nurse, you’ll recognize how these changes impact the body systems in older adults and consider conditions that can develop as a result.

Starting with age-related changes of the cardiovascular system, the heart’s muscle loses tone and becomes stiffer. To compensate, muscle mass increases, but is a less effective pump. This decreases cardiac output and increases the risk of heart failure. The heart valves become thicker and calcified, which can lead to valve disease and murmurs. Additionally, the conduction system, including the sinoatrial node, known as the pacemaker of the heart, loses cells, decreasing heart rate and increasing risk for arrythmias.

Also, blood vessels become stiffer, decreasing venous return from the periphery and contributing to dependent edema and varicosities; and the build-up of atherosclerotic plaque within the vessels can lead to coronary artery disease, peripheral artery disease, and hypertension.

Lastly, an impaired baroreflex, which helps maintain blood pressure by adjusting heart rate, cardiac output, and peripheral vascular resistance during position changes, can result in orthostatic hypotension and an increased risk of falls.

Okay, moving on to changes to the respiratory system. There are certain age-related changes that increase the risk of respiratory infections like pneumonia and influenza. These include fewer cilia, that trap and remove inhaled microbes and debris; fewer pulmonary macrophages, which are the first line of defense against inhaled pathogens; and a decreased cough reflex, which is needed to help expel inhaled pathogens and clear secretions.

Other changes include thoracic muscle weakness and calcifications of rib cartilage, which can limit lung expansion, increase the work of breathing, and decrease the ability to take deep breaths. Lastly, loss of alveolar elasticity, decreased alveolar surface area, and fewer pulmonary capillaries result in reduced gas exchange, which impairs oxygenation.

Next up, in the gastrointestinal system, receding gums and loose or missing teeth can decrease the ability to bite and chew, potentially impairing nutrition. Nutrition can also be affected by dysphagia, or difficulty swallowing, due to reduced esophageal motility; decreased gastric secretions needed for digestion; and increased gastric pH that can alter the absorption of nutrients.

Additionally, aging leads to decreased liver size and enzyme production, which can impair drug metabolism, increasing the risk of medication toxicity. Older adults also typically have diminished thirst perception, which can result in dehydration and constipation, and is further compounded by slowed gastric motility. Lastly, the lower esophageal sphincter loses tone over time, increasing the incidence of gastroesophageal reflux disease, or GERD.