Synopsis :
As children, our curiosity about what to expect as our bodies change is met with knowledge and patience. But when we're 50 or 60, our bodies undergo other dramatic (and often just as startling) changes - yet there's no one to prepare us, educate us, or provide guidance on what's "normal." From superficial concerns and everyday aches and pains to more serious medical problems, Dr. John Whyte, chief medical expert for the Discovery Channel, cuts through the confusion. In "Is This Normal?" he answers a broad range of questions about the physical effects of aging, such as: How much weight gain is normal as we age - and why is it so hard to lose? Is it normal to sleep less at night and nap more during the day? And, what are the signs of Alzheimer's versus normal memory loss? With compassion, reassurance, and friendly guidance, Dr. Whyte provides both male and female readers with cutting-edge advice for the effects of aging they face every day, from hormones and libido to cancer risk and cardiovascular health. "Is This Normal?" arms readers with the essential knowledge and preventive strategies they need stay healthy and vital for decades to come.
Extrait:
Chapter 1
ON THE OUTSIDE
|True or False | |There's nothing you can do to improve the look of wrinkles. |____ | |As you age, you don't sweat as much. |____ | |You don't need sunscreen as you get older. |____ | |Everybody loses some hair with age. |____ | |(Answers at end of chapter) |
What do you know about your skin? I bet you didn't know it is the body's largest organ! (I'll let you in on a secret: Medical school professors always ask medical students, "What's the body's largest organ?" There's always a lot of giggling and even some blushing until they hear the answer.) On one level, the role of skin is pretty simple: It helps protect your internal organs from the outside environment. It also allows you to handle many things that are dirty or dangerous--like a baby's soiled diaper or that scary container in the back of the fridge--without worrying that germs will get into your bloodstream.
There's a lot more to your skin, though, than just keeping the germs out. For instance, skin helps you maintain your body temperature. It contains your sweat glands, which cool you down in the summer and keep heat in on a chilly winter day. Your skin plays a big part in maintaining fluid balance, too. You might have heard that burn victims need huge amounts of fluid to keep them alive; that's because their skin has become so damaged that it can't keep enough water inside their bodies to maintain organ function.
Skin also alerts us to what's going on in the outside world. You might not have eyes in the back of your head, but I bet you know when someone is standing behind you and literally breathing down your neck. The nerve endings in your skin also warn you when the stove is hot, let you know that your drink needs ice even before you taste it, and tell you when it has just started to rain.
As you age, your skin undergoes a lot of changes. Some of these changes are inevitable, but others are preventable or can at least be delayed for a while. When it comes to age-related skin changes, wrinkles are the first issue that comes to mind for most people. But wrinkles are only one effect of our skin's aging process; as we approach middle age and beyond, our skin will undergo changes in texture, strength, and resilience. You're going to see some new spots and bumps. Some of these are more bothersome than dangerous, while others should send you right to the doctor. In other words, some changes are a normal part of aging, and some are not.
Don't panic. While wrinkles may be inevitable, getting older doesn't have to be a disaster for your skin. Knowing what to expect can help you take steps to protect your skin and keep it healthy as it ages with you.
STRUCTURE OF THE SKIN
Your skin is made up of three layers:
. Epidermis . Dermis . Hypodermis
Knowing a little bit about the functions of these layers and what they contain will help you understand the normal changes that come with aging as well as what you can do to keep your skin looking and feeling healthy.
Epidermis
The epidermis is the top layer--the one you see every day. The cells in this layer are renewed constantly, with the whole cycle of renewal taking about a month. That's right--you basically get a whole new layer of skin every month. Most of the cells in your epidermis are keratinocytes, which are largely dedicated to protecting the more sensitive, deeper layers of skin. These cells create a barrier against the elements, holding in fluids and protecting us against dangerous bacteria and viruses. The epidermis also contains melanocytes, the cells that give your skin its color.
Cross section of the human skin.
Dermis
The next layer is the dermis. It holds blood vessels that feed the skin and nerves that carry sensations from it. Pressure, pain, and temperature are all recognized here. It also contains your oil glands and hair follicles. The dermis contains an important molecule called hyaluronic acid, which holds on to water to keep skin looking full and even. (We'll come back to hyaluronic acid in a little while.)
The dermis also contains collagen and elastin, two molecules that are essential to the appearance of your skin.
. Collagen allows skin to withstand physical stress without breaking or tearing. It also makes up most of the skin's mass. Without collagen, your skin would be a lot thinner and more easily damaged. . Elastin does what it sounds like: It contributes elasticity to the skin. It lets skin "bounce back" from pressure and from everyday bumps and collisions. Think of elastin as a new crisp, tight rubber band.
Hypodermis
Underneath the dermis is the hypodermis. "Hypo" is derived from Greek and usually means "low" or "insufficient." But in anatomical terms, "hypo" means "below" or "under." Therefore the hypo-dermis is below the dermis. This layer contains a lot of fat cells to help cushion your skin and protect you from injury. These cells also serve as insulation, to help keep your body warm.
Why Wrinkles?
When it comes to wrinkles, everyone's different. Your genetic background has a big impact on how your skin will age. If your parents and grandparents had wrinkles in their fifties and sixties, chances are you will as well. I know America is all about fairness, but some people are just genetically gifted!
Genes aren't the only reason you get wrinkles, though. One of the biggest factors for premature aging is the amount of time you've spent in the sun over the years. When we were younger, of course, we thought a suntan made us look healthy and sexy. But as we get older, we pay a price for that mistaken belief. Sun-related aging, which doctors call photoaging, is superimposed on top of your natural aging process. So if you spent a lot of time at the beach working on your tan in your younger years, you will develop wrinkles sooner than your friends who stayed in the shade.
You might have noticed that people with naturally dark skin often seem to have fewer wrinkles than those with fair skin. That's because high levels of pigment protect their skin from sun damage. Naturally dark skin, however, is not the same as dark skin from tanning.
Did you ever wonder why your face seems to be the main place wrinkles appear? It feels like a cruel joke, but there's a reason your face ages first: Your facial muscles move your skin around a lot, causing folds and creases to appear and disappear. All of that folding and creasing puts stress on your skin, and eventually those temporary creases become permanent (so your mother was right--if you make "that expression," your face really will freeze that way). Aging and sun damage contribute to the process by decreasing the skin's ability to rebound. Most other muscles in your body serve to move your bones, like when you bend your knees or pick something up with your hands.
Though we all worry about gaining fat, as we get older, we actually lose fat in the hypodermis. Along with changes to collagen and elastin, this loss of fat contributes to the sagging of skin that used to look smooth and resilient.
THE SURFACE OF THE SKIN
In addition to gaining a few wrinkles, the look and feel of your skin changes as you age. Aging skin contains less water and lipids than younger skin. Lipids consist of fats, oils, waxes, and similar substances produced in your body. Without them, your epidermis could not do its job as a barrier to the outside world. As we get older, we have fewer lipids in the outermost layer of our skin, which means we cannot hold on to water as well, and therefore we develop drier skin. Certain lipids in the top layer of the epidermis help prevent unwanted bacteria from multiplying.
Our skin also produces less sebum as we age--the stuff that clogged your pores as a teenager and caused you to break out. At the same time, the renewal of skin cells in your epidermis no longer works as smoothly as it used to. All these factors combine to make skin drier and rougher as you get older.
Have you ever noticed that your or an elderly family member's skin appears thinner or even translucent? That's also a normal part of aging, and it's made more noticeable because the blood vessels beneath the skin's surface are becoming more visible.
Our skin becomes more delicate as we age. A scrape or bump that would lead to a minor scratch on younger skin can actually cause older skin to tear, almost like a piece of tissue paper. That's because the epidermis and dermis have become more fragile, and loss of elastin decreases the skin's ability to bounce back from impact. That once fresh, tight rubber band begins to get a little stretched out over the years.
Have you noticed that you seem to sweat less these days? That's a skin change, too. As we age, the output from our sweat glands declines; this may be one reason why older adults tend to be at a higher risk of heat stroke in the summer than younger folks. When we don't sweat as much, our bodies can overheat easily. It's important for older adults to drink plenty of fluids when they're exposed to extreme heat to prevent overheating.
SUN EXPOSURE AND SMOKING
My generation didn't think much about sunscreen when we were kids, and I'm sure we're paying for it now. I wouldn't be surprised if today's children, who get slathered with SPF 50 before setting foot on the beach, have different experiences with their skin as they age. But for those of us who had a suntan every summer for most of our younger lives, sun damage is a big deal.
One of the things that happens when you get a suntan is that ultraviolet (UV) radiation from the sun causes molecules called free radicals to form in your skin. Free radicals interact readily with other molecules in your body, altering their structures. Reactions caused by free radicals damage collagen and elastin, and slow down the production of new collagen. Damage from free radicals is part of normal aging, so there's no way to avoid it completely. But staying out of the sun and wearing sunscreen when you do go outside will definitely help protect you from the worst effects of UV rays.
The sun produces two types of radiation that you need protection from: ultraviolet A and ultraviolet B rays. They're abbreviated UVA and UVB, and that's what you'll see on your sunscreen label. (There's actually a UVC as well, but the ozone layer blocks most of it out.) UVB radiation, which is mostly absorbed in the epidermis, is the main cause of sunburns. Exposure to UVB radiation also contributes to aging and can cause skin cancer. UVA light penetrates more easily into the dermis. It also ages your skin. Both UVA and UVB light can cause lasting damage, so look for sunscreens with UVA and UVB protection and a sun protection factor (SPF) of at least 15. Higher SPF numbers provide more protection but not typically much more. I recommend SPF 15 because it protects against about 93 percent of UVB rays; SPF 30 protects against 97 percent. I often see people buying sunscreen with a high SPF like 60, mistakenly thinking that it will protect them enough to stay outside all day. It won't. SPF 60 is not twice as powerful as SPF 30.
And when the sunscreen bottle says to reapply after 2 hours? Do it. It's not a marketing ploy to get you to buy more sunscreen. Sunscreen does wear off, especially when you sweat. And some of the ingredients may actually become less effective the longer they're exposed to sunlight.
I get a lot of questions nowadays about vitamin D and sunscreen. Your body makes vitamin D when your skin is exposed to UVB light. And we need vitamin D for all kinds of things: It helps keep our bones strong, our immune systems working, and our kidneys, liver, and thyroid gland functioning properly. The logical next question is if we're limiting our exposure to the sun by using sunscreen, should we take vitamin D supplements? The reality is that you probably don't need more than half an hour of exposure to the midday sun, a couple of times a week, in order for your body to make enough vitamin D.1 You can also get vitamin D from the foods you eat-- common grocery items such as milk and cereal are fortified with vitamin D, and fish such as tuna and mackerel are natural sources of the vitamin. If you do choose to take a daily supplement, I usually recommend a dosage of 400 to 600 IU per day. Don't go much above this; higher doses can be dangerous.
If you're considering taking a vitamin D supplement, be aware of your local climate: If you live in the northern United States, winter sunlight might not be strong enough to trigger vitamin D production. Dark-skinned individuals may also need some supplementation.
In addition to sun exposure, smoking is another lifestyle choice that can affect your skin. In fact, premature skin aging due to smoking even has a name: it's called smokers' wrinkles.2
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