There were many takeaways for Chinese observing the 2016 US presidential election. One was the apparent energy exhibited by the three candidates Bernie Sanders, Donald Trump and Hillary Clinton on the campaign trail, all above or approaching the age of 70.

On the Nov 8 election day, Sanders was 75, Trump 70 and Clinton 69. With long and successful careers either in politics or business under their belts, the three - all grandparents - were not only not ready to retire, but were all eager to write a new chapter in their lives.

In the United States, there is no mandatory retirement age for most professions. There are ages when people can claim their full Social Security, Medicare and other benefits, but that doesn't mean they have to leave their jobs.

In stark contrast, retirement ages are mandatory in China. Under laws enacted in 1978, men retire at 60, while women retire at 55 if they are public servants or 50 if they are blue-collar workers. There are some exceptions for people with a certain standing in the hierarchy.

It is a huge waste of human resources considering that people aged 50 to 60 are usually the most experienced in their jobs. It is especially true given that the average life expectancy in China had increased to 76.3 by 2015, compared with only 67.9 in 1981. In Shanghai, it is now 83.

Just imagine someone graduating with a PhD at the age of 30 being forced to retire after just 30 years of work, or 25 if she is a woman and face discrimination in both age and gender.

China has been considering raising the retirement age. But the rationale has mostly been that it would cover the shortfall in pension funds in a rapidly aging population, rather than tap the human capital of its population.

The plan submitted last year was expected to be officially announced this year after public deliberation. The initial plan reportedly aims for implementation in 2022 after a five-year transitional period starting this year that will raise the retirement age by about six months each year.

But Yin Weimin, minister of human resources and social security, was quoted by Xinhua News Agency as saying on March 1 that due to heavy employment pressures, the government will take a more cautious approach in formulating the new policy.

While setting an age when people can claim their social security insurance makes as much sense in China as it does in the US, a mandatory retirement age is not appropriate for many professions. The current one-size-fits-all policy does not take into account the factor that each person is different. The mandatory age for women even makes less sense.

If the Chinese are impressed by the "still young" spirit displayed by the three US presidential candidates in the 2016 election, for years many have also been "surprised" to find that the flight attendants on many US airlines are not as young as those on Chinese airlines.

Two years ago, when Shanghai-based Spring Airlines announced it was raising the maximum age of new flight attendants to 40, it made headlines in China. Indeed, flight attendants in China are mostly in their 20s and 30s.

A story posted on the website of non-profit organization American Association of Retired Persons is entirely different: Barbara Beckett, in her early 70s, recently retired after 53 years on the job with American Airlines. Beckett recalled that when she graduated from stewardess school in the 1960s, flight attendants were required to be single and could be fired if they got married, exceeded a certain weight or reached the age of 32. But that age limit was abolished in 1970.

The 2016 US presidential candidates and flight attendants certainly challenge Chinese thinking about age and retirement.

The author is deputy editor of China Daily USA. chenweihua@chinadailyusa.com