Medical experts often agree that the elderly and the very young can experience serious and adverse reactions to seemingly mundane illnesses. Simple colds or the flu can turn into pneumonia and other life-threatening situations if left untreated. The culprit is often an underdeveloped or compromised immune system.

As you age, your physiology changes. Bones become less dense, hormones fluctuate, and you may experience a weaker immune system. As a result, seniors are more susceptible to illness than their younger counterparts. But boosting the immune system by changing your diet, exercising and getting outdoors can be a way to stay healthy.

Doctors say that it is possible to boost your immune system.

The secrets lie in understanding how the immune system works — and how your everyday life can offer you greater protection.

In simple terms, the immune system is a network of cells and organs that block unwanted visitors from wreaking havoc inside of the body. Should a germ get by, the body has strong defenders that can eliminate the threat. These are known as antibodies.

When you get an inoculation, a small amount of an offending particle is put into your body so that your immune system can develop antibodies against it. Should you be exposed to that type of invader again, you will possess the antibodies to fight it.

Your immune system can lose some of its protective properties if it is faced with a constant onslaught of diseases and must overcompensate for poor health habits. But there are ways to get your immune system back in fighting shape.

1. Get plenty of sleep. Mom was right ... lack of sleep can affect the body’s ability to function correctly, which includes fending off disease. Routine sleep deprivation can definitely affect overall health.

2. Reduce stress. Stress can have a number of negative health implications.

It slowly wears away at the immune system and leaves you susceptible to a host of illnesses.

Take measures to reduce stress as much as possible to be healthier.

3. Exercise. Moderate exercise has been shown to improve immune system function. However, overdoing it and running yourself ragged can actually be detrimental. Brisk walking or bike riding can be a great form of moderate exercise. Always check with a doctor before exercising to be sure it fits with your lifestyle.

4. Engage in intimate relations. Sex causes the body to release IGA, proteins from the immune system that help the body fight infection. Feel-good brain chemicals also play a part in fending off outside invaders.

5. Drink plenty of water. As you age, the thirst reflex becomes less pronounced, and a loss of taste may mean you pass up foods with a high water content. Dehydration can wreak havoc on the body. Water is necessary to flush out toxins that could lead to disease.

6. Eat a rainbow of foods. Brightly colored foods are full of the antioxidants you need to improve health and keep the immune system in top form. Tomatoes have lycopene, berries are a great addition to your diet and beans are high in fiber that keeps the digestive system working correctly.