As the referee blew his whistle to signal halftime, Bob left the soccer field and dug into his bag to find his inhaler. Sometimes playing soccer really made his asthma flare up, and he needed to catch his breath.

Meanwhile, George sat on the bench next to Bob, eating an apple. He wasn't really hungry, but the game had started late and dinner was a long way off. He knew he needed to keep up his blood sugar to beat this other team. His doctor warned him that he had to control his diabetes if he wanted to play sports. John, another teammate of Bob and George, pulled on his sweatshirt. He had already had 2 cups of water, but he knew he'd need to drink some more before going back out onto the field. His sickle cell anemia made his legs hurt if he was cold or he didn't drink enough water.

Besides being on the same soccer team, do you know what these three boys all have in common? They all have chronic illnesses. Chances are, you know someone with a chronic illness, too.

What Does Chronic Illness Mean?

A chronic illness isn't the name of just one illness. It's a word used to describe a group of health conditions that last a long time. In fact, the root word of chronic is "chronos," which refers to time.

There are many kinds of chronic illnesses - Bob, George, and John all have very different kinds of chronic illnesses. Some illnesses (like a cold or the chicken pox) only last a short time and go away on their own, but sometimes an illness doesn't go away. Don't worry, most chronic illnesses are not contagious - you usually don't catch them from someone else. But chronic illnesses can be genetic, meaning that parents can pass the tendency to get them on to their children before they are born through genes. If a person has a chronic illness, he needs to take care of his condition for months or years.

"In a nutshell, it's a problem or condition that may limit what a person can do, that doesn't always go away," says Marisha Madrigal, a social worker who works with sick kids in California.

Does that mean a person with a chronic illness will always be sick? Not necessarily. There are hundreds of chronic illnesses - from asthma and diabetes to lupus and lung disease - and each one affects the body differently. For instance, babies born with lung disease often outgrow their illness. Kids with scoliosis often wear a brace to get better by the time they finish growing. And though some people with a chronic illness may never get rid of their condition altogether, they will definitely learn ways to manage it. They may also have to do special things to stay healthy that other people don't have to do. Some may even go into remission, a fancy way of saying somebody gets a break from being sick.

How Does a Chronic Illness Affect Someone?

Because there are so many chronic illnesses, it's difficult to say exactly what to expect. Some people with chronic illnesses aren't able to function as well as they'd like. Some illnesses might cause a person to tire easily or miss a lot of school. Other chronic illnesses may make it necessary to have to use a wheelchair or to carry around some special foods or medication.

But whatever a person uses to get through the day, chances are he's going to feel different because of it. If you know someone with a chronic illness, it's important for you to deal with the person and the situation as best as you can. This means that although it may be uncomfortable to mention someone's special needs, it would be downright silly to ignore them. No doubt, an offer to help or a few questions from you about how he feels would help you understand what's going on and how to best handle it. Best of all, it will pave the way so you two can focus on the things that make that person who he is - not just a person who has a health problem, but a person who likes soccer, loves movies, and hates math, and who just happens to have a medical condition.

How Can a Chronic Illness Affect You?

Although chronic illnesses are managed in different ways, all of them have one requirement in common: a doctor. Frequent doctor visits and doing tests to help guide treatment are often part of what it takes to manage a chronic illness. If you have a parent, sibling, or friend who has a chronic illness, chances are he'll be away from work, home, or school every once in a while - sometimes for long periods of time, depending on the illness and how severe it is. No doubt he finds it as frustrating as you do, but be patient. The doctor is helping to figure out what his body needs and what medicines and other treatments will make living with the chronic illness as easy as possible.

How It Feels to Have a Parent or Sibling With a Chronic Illness

Even though you're not sick, you may feel pretty bad when someone you love is. Maybe you feel guilty for being healthy. Or maybe you feel mad that this illness - and person with the illness - is getting all the attention and you're stuck at the doctor's office with your brother or sister when you'd rather be outside playing. Quite possibly, you're scared and want to know what to expect and how to behave. All of these reactions are understandable; lots of kids who know someone with a chronic illness feel that way.

You might have to chip in a bit, too. If a parent or sibling is often weak, you can help by doing an extra chore or two. If he's tired, maybe you'll play outside (instead of making noise inside) while he naps. You shouldn't have to change your life completely, but you might have to make a change or two. Talk to your parents or siblings to find out what they need. Just be sure and tell them what you need, too. "You don't want to change your life so much that you can't be a kid anymore," Madrigal says.

What's your best bet? Ask what your family needs and let them know how you feel. Sharing your feelings will help them share theirs. Together, you all can find a solution or ways to meet everyone's needs - not just the needs of the person who is ill. If talking to people close to you is hard, don't lose hope: there are people all over the world in the same situation. You can find them by asking your mom or dad or a doctor to hook you up with one of the thousands of support groups for friends, brothers, sisters, and kids of people who have chronic illnesses. Remember, your parent, sibling, or friend may not be able to beat a chronic illness, but if you talk and learn about it, you can help him deal with it a whole lot better.