Stephen arrived late for afternoon class and, while everyone else began to plough through the reading assessment, he managed two lines and then came to a stop. His head was down on one arm and his pen was poised over the paper. For a long time. Was he asleep?

Maybe not. Students’ writing positions are weird. The figure sprawled across an A4 pad, head touching the desk, face hidden by copy-proof encircling arms, can actually be churning out the work. So you wait to see if an A4 sheet pops out occasionally.

But Stephen? The pen dropping from his slack hand roused him and he wrote a line and stopped again. We had a word. He had been working all morning and was shattered.

Eddie is a mature student desperate to succeed. He missed a class because he slept in.

“But it’s an afternoon class,” I ventured.

“I slept till three o’clock,” he said. “That’s scary. I feel as if I lost a bit out of my life.” Eddie works when he is not attending college.

Later in the week there was Cheryl. She wasn’t asleep, she protested, “just resting her head on the mouse mat”. Her tearful story included a part-time job, a long journey every day and not sleeping at night. By the time she had finished, I was ready to say: “There, there. You go back to class and have a nice rest.”

Scientists have recently opined what mums have known for years, that teenagers are biologically programmed to go to bed late and sleep the day away. Getting into college on time and staying awake all day presents a serious challenge.

The problem isn’t confined to young students. A recent study has linked term-time working with poorer academic performance and limited job prospects. Not surprisingly, term-time working was more prevalent among students from poorer backgrounds. Results to file under “coulda told you that”. While the study was based on university students, it confirms what I suspect is happening in my classes. Part-time working is at the heart of this epidemic.

So what do we do? Sympathise? Provide pillows and duvets? Sometimes when the going gets tough, you just have to get on with it. When my three Rip Van Winkles do find employment, no doubt there will be other pressures and problems to face and I doubt if their employers will tolerate continued lateness or a propensity to snatch a few zeds when all is quiet. Since we are a vocational college, we must equip our learners for the workplace and that includes instilling the importance of - well, staying awake for starters.

Yet it is the most vulnerable students who suffer most. Learners choose to come to us and most start with the hope of doing well. But, when part-time jobs come first, when extra hours are accepted eagerly because of debt, college work suffers.

We are torn between a hard-line approach and a sympathetic response. Take the letters we send to naughty students on our programmes. Where should we stand on the attitude continuum? Be firm - “your absences have been noted, one strike and you’re out”. Or should we tread delicately, invite them for a chat any time they can manage and urge: “Please don’t be offended, we know you’re busy, and we’re sorry if the postie woke you delivering this letter.”

It’s not much fun teaching students who are tired all the time. But dealing with an epidemic of sleeping sickness - now that can keep you awake at night.

Dr Carol Gow lectures in media at Dundee College.