Your lifestyle can affect how well your immune system can protect you from germs, viruses, and chronic illness. Replacing bad health habits with good ones can help keep your immune system healthy. Check this list to see where you could use some improvement.

1. You're short on sleep. You may have noticed you’re more likely to catch a cold or other infection when you’re not getting enough sleep. Studies help bear out that well-rested people who received the flu vaccine developed stronger protection against the illness. Not getting enough sleep can lead to higher levels of a stress hormone. It may also lead to more inflammation in your body. Although researchers aren’t exactly sure how sleep boosts the immune system, it’s clear that getting enough - usually 7 to 9 hours for an adult - is key for good health.

2. You don't exercise. Try to get regular, moderate exercise, like a daily 30-minute walk. It can help your immune system fight infection. If you don't exercise regularly, you're more likely to get colds, for example, than someone who does. Exercise can also boost your body's feel-good chemicals and help you sleep better. Both of those are good for your immune system.