Expansion
Progressive loss of muscle mass, strength and function with age
Expansion
Changes with age
- Muscle mass falls by about 1 per cent a year after 50; strength falls faster, at about 2 to 3 per cent
- Preferential loss of type II fibres, so power declines more than endurance
- Loss of motor units with reinnervation of orphaned fibres, giving larger, less finely controlled units
- Anabolic resistance: a given protein or exercise stimulus produces a smaller synthetic response
- Fat infiltration of muscle, reduced mitochondrial function, and low grade inflammation
Consequences: falls, fractures, reduced mobility and independence, insulin resistance, and poor reserve for illness or surgery.
Frailty is the broader syndrome of reduced physiological reserve across multiple systems, of which sarcopenia is a core component.
Interventions with evidence
- Progressive resistance training, which is effective even in the very old and in nursing home residents
- Adequate protein, about 1.0 to 1.2 g/kg/day in older adults, higher than the general recommendation because of anabolic resistance
- Vitamin D correction, and treating contributing illness
Prevention of immobility during hospital admission is one of the most effective practical measures.