Some people have stronger immune and defense systems as they hardly suffer from colds, fever and flu. It's likely not luck and it's not surprising, as certain habits have helped these people remain in the best of health. How do they do it? The secrets are below:

1.) They drink plenty of water regularly. The healing properties of water is ancient knowledge and studies have been done to attest that it can help ward off colds and flu. "'Everyday health complaints can be improved and even eradicated simply by drinking the recommended amount of water," said Dr. David Lewis, who did a study on water's benefits, according to Daily Mail.

2.) They keep themselves active either with exercises or any physical activity. This provides regular workouts to the heart, which boosts the immune system and lowers stress hormones, according to the National Institutes of Health. Being physically fit makes a body stronger in fighting the virus.

3.) They avoid stress. Healthier people know how to "chill out" and they engage in hobbies that relax them. Apart from enjoying these activities, their bodies are benefiting from it because - like exercise - these also boost their immune systems.

4.) They have a diet rich in vitamins and minerals and they stay away from foods with high calories. One way to do that is to put brewer's yeast on cereals, sauces and soups, or drink with a glass of water. Brewer's yeast contain B-complex vitamins that break down fats and carbohydrates into energy that the body needs, according to the University of Maryland Medical Center.

5.) They go to their doctors for regular visits. Healthy people know that maintenance is important, so they don't skip the annual check-ups and take their flu shots as recommended. Doing so helps nab any health problems even before it happens, according to the Center for Disease Control.

6.) They sleep more. "Sleep is part of our own nature's defense against illness," said Dr. M. Safwan Badr from the American Academy of Sleep Medicine, according to NBC News. Aside from getting at least six hours of sleep or more each night, healthy people follow routine sleep and nap times. 

7.) They wash their hands regularly. Some might think this is a quirk or obsession, but hand-washing is the first defense to avoiding sickness, according to the Mayo Clinic. This lowers the possibility of germs entering the body's system and there's no harm in doing it as often as necessary.