Tanzania, Aug. 13 -- Dar es Salaam. Reaching the age of 40 or above is associated with experience, confidence and professional maturity but for some workers, those years are increasingly becoming a source of anxiety in the workplace.

Concerns over age discrimination are emerging as some employees and younger colleagues associate older workers with resistance to technology, limited adaptability and declining productivity.

For workers affected, the discrimination is not always expressed through formal policies. Sometimes it comes in casual remarks, jokes or assumptions about what people in their 40s and above can or cannot do.

Paul Jonas, 44, an employee at a bank whose name he asked to be withheld, experienced such first-hand during a s...