What happens when you don't sleep enough, skip breakfast, don't exercise, or hold grudges? Find out how these behaviors are harming your health.
What happens when I only sleep five hours?
The inside story: No one knows for sure why sleep is necessary, but there's no doubt that getting too little throws a wrench into your body's works. For example, studies show that a sleep debt lowers levels of the hormone leptin, which helps keep your appetite under control. Implication: Sleep too little, and there's a good chance you'll be soon overeating. Sleep deprivation also boosts levels of stress hormones, which prompt your body to send more glucose into your bloodstream. Too little sleep also makes your body less sensitive to insulin.
But that's just the beginning. Research shows that sleeping too little shuts down production of certain chemicals in the immune system that defend your body against germs. Shortchange yourself on shut-eye and you may want to have a box of tissues and cough medicine handy: A 2009 study found that people who sleep less than seven hours a night are up to three times more likely to develop a cold.
Other studies show that even modest sleep deprivation - cutting back from your usual eight hours a night to six hours, for instance - can turn up levels of chronic inflammation, which increases the risk for many conditions, including heart attacks, strokes, and osteoporosis.
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Then, there are the immediate effects. When the alarm clock blares you out of a deep sleep, you're apt to start the day in a sour mood. As the day passes, you're also likely to feel dull witted and foggy. Some neurologists believe that one purpose of sleep is to give your brain a chance to build and strengthen the wiring between neurons. Studies show that well-rested people learn new information faster and have sharper memories. Short sleep reduces your reaction time, too, making you at risk for car accidents and other mishaps.
BOTTOM LINE: While some people can get by on relatively little sleep, most of us need seven to eight hours a night. Experts say one sign that you're getting adequate sleep is that you can wake up on time every day without using an alarm clock.
What happens when I skip breakfast?
The inside story: When you wake up after a long night's rest, your body has gone as much as 12 hours without a meal. That means one thing: You need fuel. More precisely, it means there's probably a shortage of glucose in your bloodstream. If you don't eat breakfast and head out the door with low blood sugar, one organ in particular won't be operating at full speed: your brain, which requires a steady flow of blood sugar to run effectively. And even a mild case of low blood sugar can leave you queasy and jittery. You may also feel less sharp-witted. Studies of school children have shown repeatedly that kids who eat breakfast have better memories and learn more than their classmates who don't.
What's more, blowing off breakfast is a set-up for pigging out later on. "Breakfast is important for keeping your appetite under control the rest of the day," says endocrinologist Suma Dronavalli, MD, of the University of Chicago Medical Center. In other words, skip breakfast and by noontime your groaning stomach will convince you to skip the salad and order a Dagwood-size sandwich, instead. Most people more than compensate for the calories they miss at breakfast by overeating at lunch and dinner - especially foods high in saturated fat, the kind that plugs arteries.
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Meanwhile, breakfast skippers are also more likely to snack on junk food between meals. One study found that women who usually nixed breakfast were able to take off four pounds - simply by adding a nutritious meal in the morning. Eat breakfast regularly and you'll not only lose weight, but your blood sugar should shape up, too.
BOTTOM LINE: More than three quarters of people who lose weight and keep it off eat breakfast. Sitting down for the morning meal may also make you up to 50 percent less likely to develop insulin resistance, the problem that causes type 2 diabetes.
What happens when I spend the day sitting around?
The inside story: Remember that old saying "the devil finds work for idle hands"? Spending a lazy day on the sofa may not seem evil to you, but your body finds plenty of ways to make trouble with the sugar, or glucose idling in your bloodstream. Taking a walk or getting any other type of physical activity forces muscle cells to soak up glucose, which it uses to produce energy. On a day when you don't give your muscles enough work to do, glucose goes unused. Over time, a sit-around lifestyle encourages two major problems:
* Your body converts some unused sugar to fat. Build up too much and your butt, thighs, and belly will expand. The latter flab depository is the most worrisome; research shows that fat cells around the waistline produce chemicals that cause insulin resistance and low-grade inflammation, which promotes heart disease and other conditions.
* Having lots of glucose lingering in the blood increases levels of dangerous compounds called AGEs that damage nerves and blood cells. That's why high blood sugar causes diabetes complications such as blindness and kidney disease.
Getting up off the sofa and heading out the door for a walk can help you to avoid these fates, of course. Exercise is a reliable fat burner and research shows that physical activity lowers levels of AGEs, too - among many other benefits.
BOTTOM LINE: Sitting around all day may help you get caught up on your favorite cable shows, but it is also a set-up for bad blood sugar, weight gain, and all the problems they can cause.
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What happens when I spend the day really angry?
The inside story: There's nothing wrong with getting angry - it's perfectly natural and healthy to get ticked off now and then. Staying angry is another matter altogether: It's terrible for you. Apart from wrecking your mood and alienating others, fuming all day can make it much harder to manage diabetes. Anger is a form of emotional stress, which causes your body to release adrenaline and other related hormones. One effect of these "stress" hormones is to raise blood sugar. Also, stress may make you indulge in bad habits, such as eating junk food, which can make matters worse.
There's more. Letting your anger boil all day can damage your heart. Do you get irked and annoyed now and then, but you're able to shrug it off? No big deal. But scientists now know that clinging to anger raises blood pressure. While that's not a big surprise, a recent Yale study found that people who tend to let their anger stew also have high levels of a substance called endothelin, which is known to trigger heart attacks by causing plaques in the arteries (clumps of fat, cholesterol, and other gunk) to burst open and form blood clots. Other research has found that intense, sustained anger can actually cause an arrhythmia, or irregular heartbeat, which can stop your ticker from ticking - permanently.
BOTTOM LINE: Day-long anger can be toxic, so find a way to let it go. Write down your rage in a journal. If a friend or family member made you mad, tell 'em. Or just go outside and scream - whatever helps you blow off steam.