Aging is not without its joys -- or surprises. While of course everyone's experience as they move into the middle years is different, here are a few universal truths that nobody tells you about.

1) You sweat less.
Actually, you just perspire differently. The need for underarm anti-perspirant diminishes and instead you likely will wish you could shower with a similarly purposed product after hot flashes. But speaking strictly to sticky armpits here, you can easily save money on deodorant. While your underarms may not stay dry as a bone, there is definitely less action occurring there. It's because as we age, our sweat (eccrine) glands shrink and become less sensitive.
A study in the Journal of Applied Physiology found that women aged 52 to 62 sweated less than those aged 20 to 30, which they attributed to "a diminished response of the sweat glands to central and/or peripheral stimuli" and "an age-related structural alteration in the eccrine glands or surrounding skin cells."

2) Your teeth are less sensitive.
No, it's not because you have fewer of them. If you have been suffering from teeth that are overly sensitive to hot or cold, the good news is that as you age, more dentin -- the inner hard tissue -- forms between your teeth enamel and nerves. This extra insulation results in diminished pain response, says the International Dental Journal. Of course, as your gums recede there may be more root exposure, but that's another problem for another day. For now, bring on the Ben & Jerry's.

3) You catch fewer colds.
Remember when everyone advised you to put your toddler in preschool so he could be exposed to all the other germy kids? Same idea here. By the time we reach middle age, we've been exposed to more cold viruses and have thus developed immunities to them so we get sick less. The American Lung Association says that the average adult catches a cold between two and four times a year, whereas young children get them six or eight times a year. Flu viruses are something else though. You still need flu shots every year because flu viruses mutate.

4) You may not get migraines anymore, at least if you are female.
One of the weird and wondrous side effects of menopause is that it chases away migraines in about 67 percent of the time for migraine sufferers, says the British support group, Migraine Action. That's because hormonal migraines usually stop after menopause, when hormone levels are consistently low. If you are a man, or if your migraines have a different cause, well, pass the caffeine and Excedrin.

5) Sun feels good but isn't really.
If you poured baby oil on your body when you were a teenager, please raise your hand. OK, will those folks kindly go make an appointment at your nearest dermatologist? Sun, whose heavenly rays warm our bones, soothe our sore muscles and lift our spirits, turns out to be not-so-good for us. While it's not so good for everybody, it is especially not so good for midlifers. Sun damage to our skin is cumulative. That means that the longer our exposure, the more damage we are causing. So the good news is that we can now lather up in SPF 4 billion and enjoy the beautiful beaches of the world from under a shade umbrella and wearing a head to toe coverup.

The easiest and least expensive way to keep your skin healthy and young looking is to stay out of the sun. Sunlight is a main cause of the skin changes we think of as aging — wrinkles, brown age spots, dryness. And then of course there is the risk of skin cancer -- the most common type of cancer in the United States. According to current NIH estimates, 40 to 50 percent of Americans who live to age 65 will have skin cancer at least once. Despite the baby oil beginnings, I'd like to be in the half who don't.

Earlier on HuffPost50:

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  • Exercise

    Exercising does more than improve your exterior. Several studies have found <a href="http://well.blogs.nytimes.com/2010/01/27/phys-ed-how-exercising-keeps-your-cells-young/" target="_hplink">an active lifestyle keeps your cells young</a>, according to <em>The New York Times.</em>

  • Eat Carrots, Pumpkin and Squash

    These orange veggies are chock full of the phytonutrient alpha-carotene, which <a href="http://www.latimes.com/health/boostershots/la-heb-alpha-carotene-112310,0,2855017.story" target="_hplink">lowered the risk of dying from cancer and cardiovascular diseases</a> in a study, according to <em>The Los Angeles Times</em>.

  • Avoid Too Much Sun

    Sun worshippers, take heed: Between <a href="http://www.who.int/uv/faq/skincancer/en/index1.html" target="_hplink">two and three million people are diagnosed with skin cancer</a> globally each year, according to the World Health Organization. With May being Skin Cancer Awareness Month, <a href="http://www.thirdage.com/skin/skin-cancer-awareness-month">Third Age has tips on how to avoid the "potentially fatal cancer."</a>

  • Have Sex

    A ring-a-ding-ding! Dr. Braverman of <em>The Doctors</em> suggests <a href="http://www.thedoctorstv.com/main/content/Anti_Aging" target="_hplink">having sex at least two times a week to help "reboot the brain</a>."

  • Take Your Omega-3s

    Studies suggest that foods rich in this fatty acid may reduce your risk of Alzheimer's.

  • The Computer-Exercise Combo

    <em>Huff/Post50</em> recently reported on a study that had subjects <a href="http://www.huffingtonpost.ca/2012/05/01/preventing-memory-loss_n_1465789.html?ref=fifty&ir=Fifty&just_reloaded=1">do moderate exercise and use a computer, which resulted in increased memory function</a>.

  • Up Your Glutathione Intake

    <a href="http://communities.washingtontimes.com/neighborhood/quality-life-concierge/2012/apr/16/glutathione-anti-aging-machine/">Glutathione is a rock-star antioxidant found in the body's cells</a> that "neutralizes harmful free radicals," and keeps cells running smoothly, <a href="http://www.webmd.com/food-recipes/features/glutathione-new-supplement-on-block" target="_hplink">according to WebMD</a>. To attain these benefits, eat a diet loaded with fruits and vegetables.

  • Own A Pet

    While there are conflicting reports on whether or not pets will add years to your life, it is confirmed that <a href="http://newoldage.blogs.nytimes.com/2012/03/30/rethinking-the-value-of-pets/" target="_hplink">pets can ease stress and lower blood pressure</a>, <em>The New York Times</em> reports.

  • Limit Sugar Intake

    A spoonful of sugar may make the medicine go down, but it also "<a href="http://www.ucsf.edu/news/2012/02/11437/societal-control-sugar-essential-ease-public-health-burden" target="_hplink">changes metabolism, raises blood pressure, critically alters the signaling of hormones and causes significant damage to the liver</a>," according to three doctors at the University of California at San Francisco. In a <a href="http://www.nature.com/nature/journal/v482/n7383/full/482027a.html" target="_hplink">recent issue of Nature</a>, they argued that the health hazards of sugar are similar to those related to drinking too much alcohol.