Many physical changes associated with aging can affect productivity. Those that have been investigated include decreased cardiorespiratory functioning, reduced muscle strength and sensory deterioration. A decrease in cardiorespiratory functioning often leads to increased fatigue, according to a 1995 study. This can reduce productivity in older workers, who may be relegated to more physically demanding tasks if they lack technical skills for more cognitive tasks.
Deterioration of muscular strength has been implicated in the decline in productive work performance of industrial workers who must repeatedly lift heavy objects. Muscular endurance, however, has proven more difficult to assess. A 1991 study found that 80 percent of workers on disability in Holland were older than age 50, with nearly a third of cases due to musculoskeletal disorders. It is not surprising, therefore, that as workers employed for heavy physical labor get significantly older, their productivity declines.
Although some studies now show that improved ergonomic designs in the workplace can ease problems accompanying decreased muscular strength, the most that can be offered at this time are proactive health and strength measures to delay the onset of decreased productivity.
Another common age-related loss is sensory deterioration, such as vision, hearing and balance. The changes often progress subtly, countered by compensatory mechanisms that offset productivity declines until the very last stages of life. A 1988 study found that bus drivers who were 60-64 years old had better safety records and fewer accidents per year than any other age group.
Much overlooked and little understood is the impact of social changes related to aging, such as becoming a caregiver to a spouse or parent while employed. According to a 1989 study, the proportion of older people who act as providers and/or caregivers for disabled family members increases after age 45, affecting 20 percent of the population by age 75. It is often cited as a major reason for retirement or decreased hours worked per year, especially for older women. Familial caregiving responsibilities place a heavy burden of stress on the caregiver. Research has also found that chronic stress can reduce productivity on the job, requiring more days off, late arrivals, early departures and increased absenteeism.
Based on the research findings presented above, and on many others, there is a consensus on four factors associated with work productivity and aging.
1. Knowledge: Factual procedural knowledge relevant to the performance of one's job appears to remain stable with age.
2. Skills: Physical or cognitive procedures acquired through experience are relevant to the performance of specific jobs and not adequately measured within standard laboratory assessments.
3. Abilities: General physical or cognitive abilities that set limits on the acquisition of knowledge or skills are relevant to functioning in novel situations.