We all know that smoking, drinking and general overindulgence is bad for us. Such activities can lead to cancer, heart disease and hypertension — and the list goes on and on. How much can we reasonably get away with? It’s a question that a lot of guys have asked, especially when facing that age-old adage of “Everything in moderation.” So what is a moderate amount of alcohol? Or cigarettes? Or even caffeine?

These are tricky questions, but we'll do our best to answer them and let you know the acceptable vice intakes.

Alcohol

Slurp down a few shots or guzzle a couple of beers and the bar is buzzing. Slam a few more and the world spins like a top. Gulp another pint and you might do something you’ll regret. Drink way too much and you’ll end up in the hospital. How much can you safely imbibe in the long run before your liver screams uncle?

Well, here’s the thing: Nobody really knows for sure. Studies on alcohol consumption are spotty and even long-standing guidelines, like the ones published by the British government more than 20 years ago, are being questioned. Some studies have shown that moderate drinkers (people who have one drink a day) have lower mortality rates than teetotalers. Others suggest that guys would have to drink twice that amount before they felt ill effects.

The general consensus is that, for most people, moderate drinking is probably safe as far as acceptable vice intakes go. Not a definitive answer, but it can give you some comfort if you’re used to a snifter of brandy or a can of brew every night. If, like some guys, you have trouble having just one, you should probably steer clear of the stuff.

Cigarettes

Smoking is lethal in the long run and is a poisonous habit that almost always leads to nasty things like cancer, heart disease and lung disease. A few smokes now and again, however, can’t hurt, right? We’ve all heard stories of guys who quit after 15 or 20 years of sucking smoke. They brag about how pink and mucous-free their lungs are and how lung tissue almost always regenerates. Sorry to say, but they’re wrong. According to the American Cancer Society, studies have shown that smoking between one and four cigarettes a day can have serious effects on your health. You can probably get away with a cigarette every few months, but why take the chance? Even second-hand smoke can be lethal over time, so just put the pack down and seek help to kick the addiction. It’ll be good for you. Trust us. Where acceptable vice intakes are concerned, smoking is not one of them.

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Caffeine

Most of us drink a lot of caffeine. It’s in everything: our sweets, snacks, soft drinks, and, of course, our coffee. Many doctors will tell you to watch your caffeine consumption. Why? Let’s do a little experiment: Suck down a 20-ounce venti of the strongest java the mermaid has to offer and you’ll feel like the space shuttle 10 seconds before liftoff. Guzzle a few more before an hour is up and you could be facing caffeine intoxication, a state of extreme amped-ness that triggers restlessness, nervousness, excitement, insomnia, flushing of the face, increased urination, gastrointestinal disturbance, muscle twitching, a rambling flow of thought and speech, irritability, irregular or rapid heartbeat, and psychomotor agitation. Sounds a bit familiar, doesn’t it?

A regular, non-venti-size cup of coffee contains about 140 milligrams of caffeine. To reach the super amped-out state described above, you need to swallow about 500 milligrams. And just to give you an idea, you’d need to guzzle between 80 and 100 cups of coffee to get enough caffeine to kill yourself, or about 150 milligrams to 200 milligrams of caffeine per kilo of body mass. A 175-pound guy would need to take in about 16,000 milligrams (16 grams) of caffeine to do himself in. Not an easy task, but your local barista might be up for the challenge.

The bottom line: Have a cup of coffee in the morning, and maybe two on Thursdays (we all know what Thursdays feel like). Try not to guzzle it all day. A steady stream of caffeine can cause irritability, shortened attention spans and even hypertension.

Sleep Deprivation

If you’re the college type, you’ve likely pulled an all-nighter. Same thing’s true if you’re a night- or swing-shift worker. So you know the zombie-like feeling of intense sleep deprivation — that dreamy, fuzzy state of reluctant consciousness. Well imagine sticking it out until, well, death. It can happen, you know. Go long enough without a nap and you’ll keel over — at least theoretically. Scientists have observed the phenomenon in rats, and torturers at various gulags, prisons and hell holes have inflicted it upon humans. It seems that a person can go about 11 days without sleep before things get nasty. Beyond that you’re looking at brain damage and possibly death.

What if you’re used to getting, say, five to six hours of sleep a night? You’re not going for a world record or heading for death by sleep deprivation, but you’re pretty damn tired all the time. Studies have shown that sleep deprivation of this sort can lead to all kinds of health issues. At least, we think so. Common sense and science tells us that sleep helps with cognitive ability, memory, healing, and general sanity. There’s a difference between feeling tired and getting a life-threatening illness, however. Now, we're the last people to tell you to put off a good night’s sleep, but if you have to run on fumes for a few days, it probably won’t kill you. Then again, many men have died asleep at the steering wheel. Pay close attention to your body and mind. When you’re fatigued beyond hope, hit the hay.

Get Out of Those Vice Grips

As humans, we’re prone to overdoing things. But intentionally pushing the limits with any vice is very unwise. Moderation or abstinence (in the case of cigarettes) is the best course of action. It may be fun reading about drinking enough booze or coffee to kill an ox, but it’s no fun actually doing it.