Signs of Aging: How to Stop Time in Its Tracks

Birthdays add up, gravity kicks in -- it's inevitable -- time can take a toll on your body and mind. While genes play a huge role in how you age, there are lifestyle choices that can help slow the signs of aging.

How can you make the right choices now to reduce the effects of time later?

CBS News Medical Correspondent Dr. Jennifer Ashton said the most noticeable effects of aging start with your skin. She suggests starting with good skin care.

Video Series: Dr. Ashton's Health and Wellness

She said, "When you look at your skin -- as early as age 40 -- believe it or not, you can see signs that our skin is aging. What happens on a cellular level, there's less elastin, there's less collagen, so our skin loses volume. It loses kind of its firmness and its texture and the first thing that you can probably see with your naked eye is signs of sun damage. Eighty percent to 90 percent of the damage that occurs to our skin as we age is due to the sun."

"We all like to get that little glow," she continued. "The best thing you can do to prevent (skin damage) as early as age 20 is to start using a sun protection factor, SPF, every single day. Most people only think about it when we're going to the beach or in the summertime. Not so. In fact, when you just leave your house, go to your car, walk your dog, you're getting that sun damage. So you want to use an SPF of at least 30 every single day."

Vision can also be affected by age. Ashton suggests basic preventive measures, such as good health, good diet and not smoking.

She added, "You also want to get an official dilated eye exam starting at age 50, even earlier if there's any history or you're having any problems."

She also advised resting your eyes on a regular basis.

Ashton said, "It's not going to prevent things like glaucoma or macular degeneration, but for people who are reading all day long, looking at a computer screen, even watching monitors, just 20-20-20 rule. Every 20 minutes try to take a break for 20 seconds and focus your eyes about 20 feet away. It will make you feel better."

"Early Show" co-anchor Chris Wragge said, "I think it's affects so many people now. Because you do have the computer or the BlackBerry or the Kindle or the iPad, whatever the case may be. Your eyes are always transfixed on small writing."

Bone health is also an important factor as you age.

"People think of osteoporosis as only affecting women. Not so," Ashton said. "As we age it affects men and women. You want to do weight bearing exercise, starting again in your 20s, 30s, and 40s. And again, calcium intake very, very important. So the recommendations, the numbers you want to strive for, adults should get 1,000 milligrams a day of calcium. If you're a woman over the age of 51, you need about 1,200 milligrams a day. And everyone over the age of 71 also needs 1,200 milligrams a day. If you're not getting it in your diet in terms of yogurt, broccoli, kale, milk, you need to go for a supplement."

Also as you age, your metabolism slows. Ashton said it's "simple physics" that stop the flab from taking over.

"As you age to keep your metabolism revved, you need to eat less, exercise more, lifting weights very important. You'll burn more calories at rest."

Sleep, she added, is another important factor in limiting the effects of aging.

She said, "Seven to nine hours -- nonnegotiable."