deconditioned

Deconditioning is a decline in physical function that results from prolonged inactivity, illness, or immobilization. The term describes a state in which muscles lose strength and endurance, cardiovascular efficiency decreases, and overall energy levels are reduced compared with prior baseline. It is common after hospitalization, injury, surgery, or chronic diseases that limit activity, and it tends to occur more rapidly in older adults due to age-related changes in muscle mass and vascular function.

Causes and mechanisms include extended bed rest, sedentary behavior, poor nutrition, dehydration, and systemic illness. Physiological changes involve muscle atrophy, reduced mitochondrial density and capillary networks, lowered stroke volume and cardiac output, and a decreased VO2 max. These adaptations lead to increased fatigue with everyday activities and a lower threshold for exertion.

Signs and functional impact of deconditioning may include easily fatigued individuals, noticeable weakness, slower walking speed, reduced balance and coordination, decreased exercise tolerance, and orthostatic intolerance. Clinically, there may be measurable declines in muscle mass or strength and poorer performance on functional tests such as sit-to-stand or timed walks.

Management focuses on graded reconditioning. A tailored program combines resistance training to rebuild muscle strength with aerobic exercise to improve endurance, progressing gradually under supervision to minimize injury. Nutritional support, adequate hydration, and sufficient sleep are important, as are addressing comorbid conditions. Limiting unnecessary bed rest and incorporating physical therapy, occupational therapy, and daily activity reintroduction are common components.

Prevention emphasizes early mobilization during illness or hospitalization, regular physical activity, and attention to nutrition. For at-risk populations, structured home or community exercise programs, balance training, and fall-prevention strategies help reduce the likelihood of deconditioning. With appropriate rehabilitation, many individuals regain much of their functional capacity, though recovery can be slow and incomplete in some groups.