By Bob Martin

If work is life's best educator, then the mandatory courses for graduation ought to be manual labor, national service, caregiving and volunteer work.

I've done all four and agree with the proposition that they are the foundations for good citizenship and human understanding. Now I'd like to add a fifth: Working nonstandard hours, otherwise known as the swing shift (4 p.m. to midnight) and the graveyard shift (midnight to 8 a.m.).

Two things bring these work shifts into focus these days. The first is a forthcoming report from the International Agency for Research on Cancer that will say that the graveyard shift is a probable cancer-causing agent. The theory is that the body normally produces the tumor-fighting hormone melatonin at night while we're sleeping in the dark, but if we're working under the lights, the production process can be interrupted.

The second is the fact that every holiday season not only pulls more workers into nonstandard hours (consider Black Friday) but also sharply defines the division between 9-to-5 workers and the night crew, be it the swing or graveyard shift.

I worked the swing shift at this newspaper for more than four years. Though it was two decades ago, I well remember the feeling that set in around Thanksgiving and hung around into early January. It wasn't quite self-pity or jealousy, and it certainly wasn't shame.

Rather, it was the invisibility, the notion that you were being taken for granted. It wasn't as noticeable in the months of less activity. But when you were a no-show at the holiday parties, the Christmas Eve gathering, the Christmas dinner and the New Year's Eve bash - all because you had to work - you tended to think of yourself as out of sight and out of mind, both at and away from work.

Upon working nonstandard hours, I found that I had been guilty of the same mindset when I had been in the daytime workforce. I hadn't been concerned about the hardship or disruption endured by the nurse, police officer, night foreman, retail worker, custodial crew or waitress - nearly all of whom tended to serve the rest of us in our leisure hours. Once you work their hours, though, you quickly realize how out of step you are with the rhythms of everyday life. And with your own biological clock.

Normally one eats just before, in the middle of, and at the end of the work day. If you do that on the swing shift, though, you'll sit down to dinner at midnight - almost certainly alone. And if you're used to having several hours to unwind before going to bed, prepare to tuck yourself in at 4 a.m. On your days off, often in midweek, you'll be confused, as are your daughter's friends, who ask, "Does your daddy work?" And the probing Peco repairman, who asked me one morning, "Are you on disability?"

Such comments aren't born of malice but rather misunderstanding. Likewise, the attitudes you encounter ("People working the night shift are probably happy that they have a job" and "They chose this life, so they can unchoose it if they wish") aren't intentionally condescending but rather conveniently shortsighted. It isn't that the work is bad or the morale is low. In many cases, the late shifts create an esprit de corps. It's just that you seem forever out of whack with the flow of life. And you wish all those other people, the ones with undisturbed circadian rhythms, would be more aware of the rest of the workplace world - and lifestyle and culture.

So this holiday season I choose to remember the nightsiders. They don't want pity or patronizing. What they deserve is recognition for the essential work they do, the sacrifices they make, and the difficulties built into their daily routines. The gesture may take the form of a larger tip to a waiter on New Year's Eve, but more typically it's just eye contact, a smile, maybe a handshake - and a sincere thank you for what they do and when they do it.

Bob Martin (Inkwire86@verizon.net) is a former Inquirer editor and writer. He lives in Haverford Township.