You have no interest in being 21 again. (Neither do we.) But, oh, wouldn't it be nice to feel 21 again: The energy! The metabolism! The sense of I-can-accomplish-anything-I-set-my-mind-to!
"It's totally possible to rediscover that zest and optimism you felt when you were younger," says Caroline Adams Miller, author of "Creating Your Best Life."
"In fact, recapturing those qualities is essential to leading a healthier, happier life in the long run."
Take these simple measures to turn back your internal clock and make the date on your driver's license feel like a big fat lie.

Turn in earlier
Getting your zzz's is the simplest way to feel younger right now.
"The only time your body can truly restore itself is when you're asleep," explains Henry Lodge, M.D., co-author of "Younger Next Year for Women."
"It helps build a more vibrant body and brain."
Chances are, you're not getting as much as you need. Make up for your sleep debt by turning in early enough to get eight hours of shut-eye for six weeks straight. (Skip "The Daily Show" and leave the dishes in the sink!)
After six weeks, the time it takes to form a lasting healthy snooze habit, you'll feel the difference (more energy, fewer dark circles).

Eat revitalizing food
While you're turning that sleep deficit into a surplus, age-proof your meals, too.
"Front-load the healthy stuff," Lodge advises. "Start every meal with a fruit or vegetable and a tall glass of water."
Loading up on the vitamins and antioxidants in fruits and veggies will make you feel refreshed, recharged, and reenergized. And no need to always skip dessert:
"As long as 90% of your food choices are healthy, allow yourself to indulge in that remaining 10%," Lodge says. "When you have an ice cream cone, really, truly enjoy it!" Just like you did when you were a kid.

Pump some iron
The right kind of strength-training can help you feel 10, 20, even 30 years younger, says Bob Greene, trainer and author of "20 Years Younger."
"When done properly, weight-training makes microtears in the muscles, which leads your body to generate thicker, stronger muscle fiber."
Strengthening your muscles in this way leaves you less vulnerable to injuries and builds your stamina. Greene advises focusing on your lower body and core:
Use a set of dumbbells and do a combination of squats, lunges, and calf-raises -- two to three sets of 10 reps two to three times a week. It won't be long before you'll be giving those 20-year-olds at the gym a run for their money.

Be (a little!) vain
True, getting nipped and tucked is not the golden ticket to eternal youth. But don't underestimate the power of taking care of your looks (covering your grays, buying a fancy face cream).
"There's a big difference between going crazy trying to look 10 years younger and trying to look your best at whatever age you are," says Vivian Diller, Ph.D., author of Face It. "Prolonging the vitality of your skin, your hair, and your body will make you feel more confident and youthful."
So enjoy that salon visit, guilt-free!

Mix it up
Even if you eat right, pump iron, and apply that fab face cream, doing these things in the same order every day is going to start feeling, well, old.
"The brain craves novelty," Miller says. "To feel younger, you have to stimulate it with new associations and new things."
Miller calls it electro­shock therapy for your behavior, but it's not as painful as it sounds. Just make little, out-of-the-ordinary changes like stopping at a different café for your morning latte or trying out a new running route in your nabe.

Step back in time
Did you love punk rock music in college? Load some Sex Pistols tracks on your iPod. You might think that being so nostalgic would make you feel ancient, but research shows it can have the opposite effect.
In one study at Harvard University, people who were placed in an environment that resembled their youth -- with movies, music, and memorabilia from the past -- experienced marked improvements in their memory, vision, happiness level, and overall health.
"It shows that our mind-set is what limits us," says lead researcher Ellen Langer, Ph.D., author of "Counterclockwise."
So do something that really takes you back (like re-reading your Anne Rice paperbacks!).

Play up the positive
It's natural to be a bit more gloomy than you were at 18, since time often exposes just how cruel (natural disasters, divorces, job losses) the world can be. That's why the final step to feeling younger is nixing your inner naysayer.
"The goal is not to deny the less-than-pleasant stuff that is happening, but rather to focus on what's going well," says Elizabeth Lombardo, Ph.D., author of "A Happy You."
If the flight for your romantic vacation gets delayed, remind yourself that you're on your way to a great destination with your mate.
"Cultivating a greater sense of optimism will provide you with more positive energy to motivate you to do youthful things," Lombardo explains.
You know, like sneaking kisses while you wait for that next flight.

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