This is how it starts. At 2:20 a.m., 23-year-old Aisha Marcelina tiptoes quietly to the bathroom so she doesn't wake her family. She lays out her uniform, gets dressed, has a quick breakfast, then she gets on a bus and travels almost two hours to start work at 6 a.m. For free.

"Before I started volunteering here, I used to sleep in until really late," she says. "But now I'm getting more into the habit."

Marcelina had planned on buying tickets to the Olympics. Now as a volunteer, she's here four days a week, though she doesn't get to watch a single event. Her job is to chauffeur officials and athletes around the city. Shortly after 6 a.m. she punches in and grabs the keys to the black car covered in Rio 2016 decals. Marcelina says she's enjoying the cultural exchange, even learning some new words.

The IOC says about 30 per cent of the volunteers aren't showing up, which means those who do face longer shifts. (Kim Brunhuber/CBC)

"Xie xie, arigato," she says from behind the wheel, and laughs as she tries out "thank you" in Mandarin and Japanese.

She's a cog in the engine that drives the Games‚ among the more than 50,000 volunteers who have come here, on their own dime, from around the world. It can be a boring, often thankless job. And, Marcelina says, problems have started cropping up.

"They ask us to come to work really early and then hold us back when it's time to go home," she says.

That's because Olympic organizers are scrambling to fill holes now that about 30 per cent of the volunteers aren't showing up.

Rio 2016 spokesmann Mario Andrada says they're 'fine-tuning' some of the issues affecting the volunteers. (Olympic Broadcasting Services)

Outside the volleyball venue at Copacabana Beach, Luis Moreira is waiting for the night session to start. Last week, he might have been the one holding the neon stick waving ticket-holders in. He had volunteered for these Games to be part of history‚ but his work schedules were always jumbled and there wasn't enough food. So he quit.

"Many volunteers had to quit because they had to work two weeks in a row, schedules were messed up, lots of people quit because of the food: they were told to work eight, nine hours and were only provided with a little snack," Moreira says.

"I don't think the organizing committee had enough consideration for people's lives and welfare. It was as though the organizing committee was doing us a favour. The committee uses the volunteers to make money, uses us for free labour."

The IOC has made more than $5.6 billion US in the last four years. But paying workers, they say, is against the spirit of the Games — even though, critics point out, IOC executives in Rio are getting a $900-a-day per diem.

'Backbone of the Games'

"Volunteers are the backbone of the Games," says IOC director of communications Mark Adams. "We could do it a different way. But I think volunteers are something we really do appreciate."

Rio 2016 spokesman Mario Andrada says they're trying to fix the problems.

"We've got a task force we are working on for volunteers, and in the same way we are now fully focused to fine-tune the volunteer programs," Andrada says.

But with all the complaints, organizers now seem to be clamping down on what volunteers can say.

Thamiris Francisco is one of about 56,000 Olympic volunteers. (Kim Brunhuber/CBC)

Volunteer Thamiris Francisco, 24, spends her days in the hot sun on top of what looks like a lifeguard chair, helping ticket-holders find their venues.

She would love to tell you herself that, yes her shifts are getting longer, yes there's not always enough food, but the sacrifice for a chance to mingle with the world has totally been worth it.

But she can't, explains her supervisor. She's not allowed.