Top 10 Worst Things for Your Immune System

Top 10 Worst Things for Your Immune System

Kick these surprising habits to keep colds, flu and other bugs at bay.
by the Editors of Prevention.com

Muscle Up Your Immunity

Staying healthy isn't just about using hand sanitizer and avoiding coughing co-workers.

It turns out some pretty surprising daily habits—like how you fight with your husband or whether you stay up late for Letterman—can impact how well your body fends off colds, flu and other pesky bugs. Here's a list of science-backed tips to add to your stay-healthy arsenal today.

1. You Avoid the Water Cooler
Friendship may be Miracle-Gro for your immune system.

Research shows that the fewer human connections we have at home, at work, and in the community, the likelier we are to get sick, flood our brains with anxiety-causing chemicals, and live shorter lives than our more sociable peers. In one study, researchers who monitored 276 people between the ages of 18 and 55 found that those who had 6 or more connections were 4 times better at fighting off the viruses that cause colds than those with fewer friends.

What to do: Don't let a jam-packed workday or hectic schedule get in the way of your friendships. Stop by a co-worker's office for a quick Monday morning catch-up, or e-mail/text your friends at night to stay in touch when you're too busy for phone calls.

2. You Often Feel Tired
Scrimping on sleep has a powerfully detrimental effect on immunity.

The perfect example: college students who get sick after pulling all-nighters cramming for exams. Poor sleep is associated with lower immune system function and reduced numbers of killer cells that fight germs. In fact, University of Chicago researchers found that men who had slept only 4 hours a night for 1 week produced half the amount of flu-fighting antibodies in their blood (jump-started by a flu shot) compared with those who slept 7 1/2 to 8 1/2 hours.

What to do: Most adults need between 7 and 9 hours of uninterrupted rest every night, but how you feel in the morning and throughout the day may be a better gauge. If you're tired when you wake up in the morning, you're not getting enough—sleep, or maybe not enough quality sleep.

3. You Act Like Debbie Downer
Studies show that glass-half-empty types don't live as long as those who look on the bright side.

When pessimists put a more positive spin on the calamities in their lives, they have less stress and better health. A classic UCLA study found that law students who began their first semester optimistic about the experience had more helper T cells mid semester, which can amplify the immune response, and more powerful natural killer cells, than students who had a more pessimistic perspective. One reason could be that optimists take better care of themselves. It could also be due to less stress-related damage to the immune system, such as killer cells that suddenly become pacifists.

What to do: Personality is tough to change. Look for reasons—however small—to feel lucky every day. Sounds hokey, but try striking up a dinner table conversation with your family where you all share a couple of good things that happened every day.

4. You Bottle Up Your Moods
A constructive argument with your spouse can actually increase immunity, say UCLA researchers.

They asked 41 happy couples to discuss a problem in their marriage for 15 minutes. The researchers detected surges in blood pressure, heart rate, and immune-related white blood cells, all of which were similar to the benefits seen with moderate exercise. But you still have to play nice: Couples who frequently use sarcasm, insults and put-downs have fewer virus-fighting natural killer cells, have higher levels of stress hormones, and take up to 40% longer to recover from injuries than those who manage to stay positive and affectionate during their quarrels.

What to do: Don't keep what's bothering you bottled up. People with type D personalities—those who keep their opinions and emotions hidden—have killer T cells that are less active than those found in more expressive peers.

5. You're Under the Gun
Chronic stress—the day-after-day kind you experience over job insecurity or a sick relative—takes a toll on many aspects of your health, including immunity.

There is compelling scientific evidence that this kind of stress (as opposed to the every-now-and-again kind from a bad day at work or a screaming match with your kid) causes a measurable decline in the immune system's ability to fight disease. Periods of extreme stress can result in a lower natural killer cell count, sluggish killer T cells, and diminished macrophage activity that can amplify the immune response. In fact, widows and widowers are much more likely to get sick during the first year after their spouse dies than their peers who have not experienced a major loss.

What to do: We're not going to tell you to take a bath or light a scented candle (unless those really help you relax, that is!). Do find go-to, healthy stress relievers that can take the edge off—be it a long run on the treadmill, a relaxing yoga class, or baking dessert just for fun. The important thing is that you unwind and recover from stress, since it's often hard to avoid in the first place.