The 5 Most Terrifying Side Effects of Exercise

5 Running Makes You Poop Yourself

Congratulations -- you've decided to take up running! That'll get your ass in shape. So you lay your shoes and shorts by the bed, set the alarm to a time you've never seen on your clock before (there's a 5 A.M. now?) and prepare to embark on a journey of personal victory and a lifetime of rubbing your athletic prowess into the jerk faces of your seventh-grade gym class.

And to your surprise, you actually do it. You take off onto the dark, empty streets. All is great until suddenly, when your body detects that you are at the farthest possible point from a toilet, you realize that hitting up Bert's Taco Palace last night as a celebratory kickoff to your new life may have been a less-than-optimal decision. Welcome to runner's diarrhea.

Running is one of the more jiggly sports. Lots of impact. And the vibrations of your feet pounding on the ground over and over again hit resonance with your gastrointestinal system, causing it to, ahem, wake up. It's running's own brown note. And when it hits, you'll enter a race with Satan himself to find any amount of privacy -- if not from your own shame, then to avoid being arrested -- lest you face "the muddy walk home."

Just ask Paula Radcliffe.

Paula Radcliffe holds the world's record female marathon time at 2:15:25. And near the end of the 2005 world championship marathon, Paula straight ran herself into some problems: "I was losing time because I was having stomach cramps and I thought 'I just need to go and I'll be fine.' I didn't really want to resort to that in front of hundreds of thousands of people. Basically I needed to go. I started feeling it between 15 and 16 miles and probably carried on too long before stopping. I must have eaten too much beforehand."

She ducked behind a barrier and did what she had to do. The media, recognizing this as an unfortunate and shameful moment of internal distress, broadcast it live to the entire world.

Oh, yeah. She won that race. At 2:17:42.

That wasn't a freak accident. According to a Dutch study, 45 percent of all runners experience some form of GI discomfort on their runs. For the most part, this form of incontinence manifests itself in a sudden and undeniable urge to go now and will not necessarily explosively propel you along your running trail. With forethought and planning, you can reduce these urges and create a Boy Scout-like preparedness for when the unexpected attacks. Eat a low-fiber meal the night before, stay hydrated, plan your routes around public restrooms, wear extra-thick fluffy socks. But chances are, in time, this will affect you.

Of course, you could just take on a different form of exercise, like cycling. You know, like Greg LeMond, who won the 1986 Tour de France with a load in his shorts. Hmmm ... we would suggest trying swimming, but that brings to mind a particularly horrible image.

4 Constant, Endless Sweat

You've been doing well. Real well. You've increased your exercise time from 20 minutes a day a few days a week to an hour or more daily. You've run a 5K, a 10K. Maybe swam half a mile and stayed in the top 10 percent of the race. Hell, you bike the 10 miles to work and back daily. Your clothes became too loose to wear a while ago, leaving you with no choice but to buy a new wardrobe. A sexy, tight-fitting wardrobe with all the nipples cut out.

Things are good.

Except that you've noticed that when you go out with your (pathetically fatter, slower) friends, you're always covered in sheen of sweat while they're baby-powder dry. No, that's not exactly right. You're actively sweating. Profusely. In fact, you constantly look like you've just stepped out of the gym or perhaps a swimming pool. A swimming pool filled with armpit grease.

According to Lance Armstrong's coach, Chris Carmichael, as you become more fit you sweat sooner and you sweat more. In essence, as you increase your exercise intensity and duration, you condition your body to be better prepared for the athletic punishment you regularly put it through. This manifests itself in many ways: low body fat, increased muscle content, stronger bones, higher glycogen storage, lower heart rate. And you sweat like Patrick Ewing.

Your body knows that you're prone to taking off on 50-mile bike rides, and it has to be ready to cool you down. But it can't tell the difference between a pre-ride warm-up and a flight of stairs to your office. So to be on the safe side, it just turns the sweat faucets on and lets loose anytime your heart rate increases by an additional beat per minute.

3 Abuse to Your Feet, Nipples and "Scrotal Zone"

One of the best parts of getting and staying in shape is that it makes you sexy. And not in an artificial, plastic surgery way, but in a genuine, this-chick-can-shatter-billiard-balls-with-her-ass-muscles way.

That is, except for all the parts of your body you're now going to have to hide.

Like your feet. Your feet are gonna be ugly. People who run three miles a day three days a week or bike an astounding four-mile round trip to and from work do not have this problem. But once you step up your training and start pushing yourself to go faster and farther, you can forget about all your cute nail polishes and go ahead and burn your flip-flops. You're never wearing them again. Your feet are going to become gnarled, calloused, toenail-free hooves.

But that's feet. Except for a small group of people with a very particular fetish, most people don't find feet all that attractive. When naked time rolls around, you aren't thinking about feet -- you're thinking about more salacious things. Like nipples. Or more specifically, you're thinking about how nobody will ever be allowed to touch your nipples again.

The skin on your nipples, unlike the skin on the rest of your body, is incapable of becoming calloused. Sweat leaves behind a layer of salt. Rough, sandpaper-like salt. This plus nipples rubbing against a shirt equates to bloody nipples.

No shower has ever hurt the way a shower with a nipple that has been slowly shaved off hurts. This largely affects men, because women usually wear tight-fitting sports bras that wick away sweat and cut down on the fabric-to-nipple molestation.

OK. Feet and nipples are out. But you can still bump uglies. You're just going to have to coat your body in Vaseline like Burt Reynolds in Striptease. Moving produces friction, and no matter how fit you are, there are areas of your body where lots of bits and parts all come into close proximity to each other and spend the duration of your workout squishing and sweating and basically acting like an Abercrombie & Fitch modeling session.

This will leave you with a nice, baboon-ass red rash that looks like something you'd pick up on a "business trip" to Thailand. Plenty of products help offset chub-rub -- you just have to deal with the reality of having a can of Swamp Ass in your bathroom.

2 Swimming Can Kill You in Endless Creative Ways

We hinted earlier that if you're going to shit yourself while exercising, you might as well be in the water, where nobody would ever notice and the entire pool acts as your personal bidet. Plus, nothing bad ever happens to swimmers. Drowning? Surely a myth perpetrated by radical anti-transnatationists, right? No, swimming is perfect.

That is, unless you get brain amoebas.

Now, this is not a problem for your local swimming pool. But what can beat the ocean -- or even a lake or pond -- for swimming? And once you advance to hard-core long-distance swimming like the swimming portion of a triathlon, you'll train in open water. Doing a mile in a 50-meter pool is repetitive and involves a lot of turning and stopping. Practicing out in a river or lake prepares you for the reality of not having a floor to stand on or an edge to grab and what to do when the inevitable tentacles wrap around your leg.

As long as it isn't too warm and the lake water too cold. There are nasties living in those depths, and not just alligator gars.

We speak of ancient horrors that have existed since before time, that lie dead and dreaming. And they'll infect and eat your brain. It's an amoeba called Naegleria fowleri, and it simply drifts into your nose and latches onto your olfactory nerve. Then onto your brain. It was thought to be exceptionally rare (with only a few hundred cases worldwide since it was discovered), and then all of a sudden in 2007, six people in the U.S. died from it. The amoeba needs warm water to live, and it's thought that its sudden growth is due to, you guessed it, global warming.

Not that warm water is great for swimming anyway, despite how awesome it feels. For instance, let's talk about sweat again. You sweat while you swim, just as with any other activity, but it does nothing. It's the evaporation of your sweat that cools you under normal circumstances. That doesn't happen while you're in water, but usually that's OK, because water is a giant radiator -- the heat of your body simply washes away. Unless the water is too warm.

In which case not only is your sweating ineffective, the water isn't cooling you. We're not talking hot-tub hot, just warm. In fact, any water above 80 degrees is probably too dangerous to exercise in.

1 Your Junk Disappears

For you men out there, let's say you've decided to get even more manly by lifting heavy, manly objects and then placing them down again. Over and over, pumping those weights until your muscles fill with blood, your biceps swell, and you can see the visage of a young Schwarzenegger in your own face. After breaking a strong, manly sweat and staring at your sleek, chiseled form in the mirror, perhaps playing the tempo to the 1812 Overture with your pecs, you step into a manly shower to scrub the manly funk off your body. And it's in this shower that you discover you no longer have any balls. In fact, you've become a Ken doll.

Whether you're a runner, a cyclist, a swimmer or some parkour jackass testing the patience of gravity, you'll soon discover that extended bouts of sustained physical effort cause your genitals to shrink. And by shrink, we mean literally tuck up into your body. Thankfully, one's genitals return to normal within an hour or so. Though it probably seems like longer.

As for the ladies, well, all you need to worry about is the female athlete triad, a condition that combines poor body image, eating disorders and menstrual irregularities. This particularly strikes women who engage in sports that reward lower-mass bodies -- like running, swimming and cycling, where less mass means less to move, which means greater performance.

The low body weight along with low caloric intake leads to brittle bones and amenorrhea, the loss of one's menstrual cycle for three or more months. Depending on the sport you participate in, you can expect a 3.6 percent to 66 percent chance of developing this, compared with the 2 percent to 5 percent chance experienced by the general public.

Though we suppose that being skinny, brittle and currently unable to become pregnant makes a woman the dream girl of the male douchebag. So you, uh, have that to look forward to.

For more ways to better yourself that are a total crock, check out 6 Fitness Tips Everyone's Heard (That Don't Work at All) and 8 Health Foods That Are Bad For Your Health.