Source: MayoClinic.com

Looked in the mirror lately only to find a few more wrinkles and gray hairs? Those are just a few of the changes you're likely to notice as you get older. But what exactly is going on with your body? Here's what you can expect as you age.

Natural changes with age
Regardless of how long you live, time takes a toll on the organs and systems in your body. How and when this occurs is unique to you. Some typical changes to expect as you age include:

Cardiovascular system
Over time, your heart muscle becomes a less efficient pump, working harder to pump the same amount of blood through your body. Also, your blood vessels become less elastic. Hardened fatty deposits may form on the walls of your arteries (atherosclerosis), narrowing the passageway through the vessels. The natural loss of elasticity, in combination with atherosclerosis, makes your arteries stiffer, causing your heart to work even harder to pump blood through them. This can lead to high blood pressure (hypertension).

Bones, muscles and joints
Your bones reach their maximum mass between ages 25 and 35. As you age, your bones shrink in size and density. One consequence is that you might become shorter. Gradual loss of density weakens your bones and makes them more susceptible to fracture. Muscles, tendons and joints generally lose some strength and flexibility as you age.

Digestive system
Swallowing and the motions that automatically move digested food through your intestines slow down as you get older. The amount of surface area within your intestines diminishes slightly. The flow of secretions from your stomach, liver, pancreas and small intestine may decrease. These changes generally don't disrupt your digestive process, so you may never notice them. But you might notice more constipation.

Kidneys, bladder and urinary tract
With age, your kidneys become less efficient in removing waste from your bloodstream. Chronic conditions, such as diabetes or high blood pressure, and some medications can damage your kidneys further.

About 30 percent of people age 65 and older experience a loss of bladder control (urinary incontinence). Incontinence can be caused by a number of health problems, such as obesity, frequent constipation and chronic cough.

Women are more likely than men to have incontinence. Women who've been through menopause might experience stress incontinence as the muscles around the opening of the bladder (the sphincter muscles) lose strength and bladder reflexes change. As estrogen levels decline, the tissue lining the tube through which urine passes (urethra) becomes thinner. Pelvic muscles become weaker, reducing bladder support.

In older men, incontinence is sometimes caused by an enlarged prostate, which can block the urethra. This makes it difficult to empty your bladder and can cause small amounts of urine to leak.

Brain and nervous system
The number of cells (neurons) in your brain decreases with age, and your memory becomes less efficient. However, in some areas of your brain, the number of connections between the cells increases, perhaps helping to compensate for the aging neurons and maintain brain function. Your reflexes tend to become slower. You also tend to become less coordinated.

Eyes
With age, your eyes are less able to produce tears, your retinas thin, and your lenses gradually turn yellow and become less clear. In your 40s, focusing on objects that are close up may become more difficult. Later, the colored portions of your eyes (irises) stiffen, making your pupils less responsive. This can make it more difficult to adapt to different levels of light. Other changes to your lenses can make you sensitive to glare, which presents a problem when driving at night. Cataracts, glaucoma and macular degeneration are the most common problems of aging eyes.

Ears
Hearing loss is one of the most common conditions affecting adults who are middle-aged and older. One in three people older than 60 and half of all people older than 85 have significant hearing loss. Over the years, sounds and noise can damage the hair cells of your inner ears.

Also, the walls of your auditory canals thin, and your eardrums thicken. You may have difficulty hearing high frequencies. Some people find it difficult to follow a conversation in a crowded room. Changes in the inner ear or in the nerves attached to it, earwax buildup and various diseases can all affect your hearing.

Teeth
How your teeth and gums respond to age depends on how well you've cared for them over the years. But even if you're meticulous about brushing and flossing, you may notice that your mouth feels drier and your gums have pulled back (receded). Your teeth may darken slightly and become more brittle and easier to break.

Most adults can keep their natural teeth all of their lives. But with less saliva to wash away bacteria, your teeth and gums become slightly more vulnerable to decay and infection. If you've lost most or all of your natural teeth, you might use dentures or dental implants as a replacement.

Some older adults experience dry mouth (xerostomia), which can lead to tooth decay and infection. Dry mouth can also make speaking, swallowing and tasting difficult. Oral cancer is more common among older adults. Your dentist checks for oral cancer when you go for regular cleanings and checkups.

Skin, nails and hair
With age, your skin thins and becomes less elastic and more fragile. You'll likely notice that you bruise more easily. Decreased production of natural oils may make your skin drier and more wrinkled. Age spots can occur, and skin tags are more common. Your nails grow at about half the pace they once did. Your hair may gray and thin. In addition, you likely perspire less — making it harder to stay cool in high temperatures and putting you at increased risk of heat exhaustion and heat stroke.

How fast your skin ages depends on many factors. The most significant factor is sun exposure over the years. The more sun your skin has been exposed to, the more damage you may attain. Smoking adds to skin damage, such as wrinkles. Skin cancer also is a concern as you age. You have a 40 percent to 50 percent chance of getting skin cancer at least once by the time you reach 65.

Sleep
Sleep needs change little throughout adulthood. If you need six hours of sleep nightly, chances are you'll always need six hours — give or take 30 minutes. However, as you age, you'll likely find that you sleep less soundly, meaning you'll need to spend more time in bed to get the same amount of sleep. By age 75, some people find that they're waking up several times each night.

How long can you live?
The longest documented human life span is 122 years. Though a life span that long is rare, improvements in medicine, science and technology during the last century have helped more people live longer, healthier lives. If you were born in the early 1900s in the United States, your life expectancy was only about 50 years. Today it's around 77.

And if you're sure you've already done too much damage to yourself to hope for a long life, think again. Researchers say it's never too late to adopt a healthy lifestyle. For example, if you quit smoking now, your risk of heart disease begins to fall almost immediately. Living a healthy lifestyle can improve how you age. Eating a variety of fruits and vegetables and getting out for a daily walk are ways you can begin preparing now for your later years.