Most people start their day with a cup of coffee, a shower, a good stretch. Beth Akins rolls over, grabs her iPhone and fires up "Shake & Spell," her favorite iPhone app game.

"I usually play before I even get out of bed," says Akins, 54, of Louisville, who says a day without "Shake & Spell" leaves her with feelings of withdrawal. "I play every day."

Apps (short for computer maker Apple's applications) refers to the scores of games and services that iPhone and iPod Touch owners can download and use. There are 85,000 apps for Akins and the other 50 million users around the world.

BRAIN BUZZ

Some users can be seen strolling down work hallways and streets "apping" and bumping into others as they do.

"Clearly, the reward circuitry in the brain is getting something out of it," says Marina Picciotto, a professor of psychiatry, neurobiology and pharmacology at Yale University.

"Obviously, what it's doing to our health, it's too early to tell. There are a few parallels we can make from other addictions, like compulsive shopping. The consequences can be bad — credit debt, time lost."

One attraction: Apps are cheap (sometimes free), and the payback is fast.

There are apps that help you avoid traffic jams, one that walks you through the steps of making a perfect latte, and another that tracks flu outbreaks. There are sports apps and games galore.

Anish Acharya, 30, co-founder of socialDeck, the company that invented Akin's beloved "Shake & Spell," a Boggle-like game in which the goal is to shake up 16 little squares with letters and then spell as many words as possible in three minutes, says the draw can be a combination of social and competitive rewards.

"For some people it's just about winning and getting to the top of the leader board. For others it's an interaction with a stranger," he says. "And for others, it's just about killing 10 minutes in the line at the butcher's shop."

For Akins, her app keeps her connected with her sister, who is homebound in Athens, Ga., waiting for a lung transplant. "She can't travel, so I bought her an iPhone so she could play with me," Akins says.

USING YOUR TIME

Though some research suggests playing brain games can boost cognitive power, the downside of app overuse can include the time it takes away from family, friends, tasks such as getting your children to school on time, and health needs such as sleeping, Picciotto says.

Users should keep tabs on whether apps are taking over their lives, says Hilarie Cash, a psychotherapist and co-founder of reStart, a Fall City, Wash.-based Internet-addiction recovery center that opened this summer.

"If you are spending two hours or more a day engaged with your digital equipment and it's not for work- or homework-related reasons, then you've got cause for alarm," Cash says.

Jim Sun, 47, a father of four from Anaheim, Calif., has downloaded about 60 apps to his iPod Touch. They've replaced TV and some family time, Sun says, "and definitely sleep."

Over-apping may overwhelm the brain, says Gary Small, author of "iBrain" and a professor of psychiatry and biobehavioral sciences at UCLA's medical school.

"When we're constantly scanning the environment, waiting for the next bit of info from our devices, I think it puts our brain into a stressful state, and stress is not good for the brain," Small says.

THE BODY'S IN PLAY

App abuse can have purely physical repercussions, too, such as carpal tunnel syndrome from repetitive hand movements, Picciotto says. Akins says her neck aches after too many games in a row.

And what happens to app addicts when an iPhone falls into a puddle or is accidentally left behind?

Small says withdrawal feelings suggest that dopamine receptors in the brain aren't getting their fix.