| dysphagia incidence increases | — | oropharynx, oesophagus | Human | |
| Beta-amyloid protein deposition increases | — | brain | Human | |
| forced vital capacity decreases | — | lung | Human | |
| Increase in IgA | — | intestine | Human | |
| ventilatory rate at maximum exertion decreases | — | lung | Human | |
| increase in amplitude and duration of peristaltic pressure wave in hypopharyngeal sphincter | — | hypopharynx | Human | |
| Decreased ability to maintain body temperature when exposed to cold | — | whole body | Human | |
| Decrease in the 24-hour integrated concentration of GH | — | plasma | Human | |
| Parkinsonian signs | — | nervous system | Human | |
| Proportion of apoptotic cells may be increased | — | mesenchymal stem cell | Human | |
| Declining T-lymphocyte production in the thymus | — | thymus | Human | |
| neurofibrillary tangles and Lewy bodies in neurons | — | brain | Human | |
| Glomerular filtration rate declines | — | glomerulus | Human | |
| increase in follicle stimulating hormone (FSH) and luteinizing hormone (LH) preceding menopause | — | plasma | Human | |
| proliferation is reduced | — | lymphocytes | Human | |
| Body temperature decreases with age | — | whole body | Human | |
| circadian plasma melatonin flattened | — | plasma | Human | |
| Alterations in structural proteins and cell membranes in the lenses | — | lens | Human | |
| Changes in fat distribution | — | adipose tissue | Human | |
| vaccination antibody response is impaired | — | immune system | Human | |
| body temperature circadian rhythm flattens | — | whole body | Human | |
| postprandial serum bile acids decrease | — | alimentary system | Human | |
| prefrontal cortex activation during learning is reduced | — | brain | Human | |
| Circadian Rhythm | — | whole body | Human | |
| morning IGF1 decline | 51.0% Decrease Hormone Level | plasma | Human | |