Towards an Age-Differentiated Assessment of Physical Work Strain

In many developed countries, the workforce is rapidly aging. Occupational demands however, have not decreased despite the fact that workers see a decline in physical work capacity with age. The purpose of this review is to examine the physiological adaptations to aging, the impact of aging on performance and the benefits of physical fitness in improving functional work capacity in aging individuals. An extensive search of the scientific literature was performed, acquiring published articles which examined the physiological changes associated with age-related decrements in the physical work capacity of healthy aging adults. The databases accessed included AARP Ageline, AccessScience, Annual Reviews, CISTI, Cochrane Library, Clinical Evidence, Digital Dissertations (Proquest), Embase, HealthSTAR, Medline, PubMed, Scopus, and PASCAL and included relevant information sites obtained on the world wide web. While a great deal of variation exists, an average decline of 20% in physical work capacity has been reported between the ages of 40 and 60 years, due to decreases in aerobic and musculoskeletal capacity. These declines can contribute to decreased work capacity, and consequential increases in work-related injuries and illness. However, differences in habitual physical activity will greatly influence the variability seen in individual physical work capacity and its components. Well-organized, management-supported, work-site health interventions encouraging physical activity during work hours could potentially decrease the incidence of age-related injury and illness. Age-associated functional declines and the accompanying risk of work-related injury can be prevented or at least delayed by the practice of regular physical activity. Older workers could optimally pursue their careers until retirement if they continuously maintain their physical training.

Sixteen highly trained masters endurance athletes, 59 +/- 6 yr, were compared with 16 young athletes, with whom they were matched on the basis of their training regimens, and with 18 untrained middle-aged men. On echocardiographic evaluation, both groups of athletes had a significantly greater left ventricular volume and mass than the untrained men; their were no significant differences in percent fiber shortening or velocity of fiber shortening among the three groups. Maximum O2 uptake (VO2max) averaged 15% less in the masters than in the young athletes (58.7 vs. 69 ml.kg-1.min-1). When expressed in terms of lean body mass to correct for differences in body fat content, VO2max of the masters athletes was about 60% higher than that of the middle-aged untrained men. Maximum heart rate was 14% lower in the masters athletes than in the young athletes (169 vs. 197 beats/min). The O2 pulse during maximum exercise (i.e., VO2max/heart rate at VO2max) was identical in the masters and young athletes. This finding suggests that the major factor responsible for the lower VO2max of the masters athletes, compared with the young athletes, is their slower heart rate.