7 Habits That Are Destroying Your Immune System

It’s cold and flu season, and people everywhere are terrified of being brought down by an illness spread by their kids or coworkers.

While these bipedal germ factories often spread illness by touching us or public items that we then touch after them, they’re not always to blame for your aches, sniffles or sore throat.

Lifestyle and diet choices often determine whether you get sick more than your germ-y acquaintances.

Keep reading to discover several ways your habits could be putting you at risk this cold and flu season.

1. SMOKING

It boggles the mind to think that with all the known health consequences associated with tobacco use, some people still do it. But if you’re smoking this cold and flu season, know that the nicotine exposure is making your immune system a sitting duck for illness. Yes, even if you’re smoking e-cigarettes.

Nicotine increases cortisol levels, while reducing B cell antibody formation and T cells’ response to antigens. A study published in PLOS One last February also found that vapor from e-cigarettes may damage the lungs and make them more susceptible to infection. If you hate wasting PTO days because you’re sick, now’s the time to quit smoking for good. 

2. EXCESSIVE DRINKING

Drinking too much is a one-two punch for your immune system. First, it deprives the body of valuable immune-boosting nutrients. Second, “alcohol, like sugar, consumed in excess can reduce the ability of white cells to kill germs. High doses of alcohol suppress the ability of the white blood cells to multiply, inhibit the action of killer white cells on cancer cells, and lessen the ability of macrophages to produce tumor necrosis factors,” explains Dr. Sears. “Damage to the immune system increases in proportion to the quantity of alcohol consumed. Amounts of alcohol that are enough to cause intoxication are also enough to suppress immunity.” Remember that at all your holiday parties.

3. LACK OF SLEEP

Sleep is the time when your body recharges and heals. If you’re not getting enough sleep, your body is denied the downtime that’s necessary to stay on top of invading pathogens. “Previous studies have associated sleep restriction and sleep deprivation with the development of diseases like obesity, diabetes and hypertension. Others have shown that sleep helps sustain the functioning of the immune system, and that chronic sleep loss is a risk factor for immune system impairment,” reports The Sleep Foundation.

4. STRESS

Ultimately, a lack of sleep triggers the same response as chronic stress. Although we might not realize it, the physical and emotional demands of our everyday responsibilities can indeed drain our immune system’s ability to fight off bacteria and viruses. When your body is constantly fighting to repair the damage caused by stress, it has fewer resources available to address invading pathogens. 

5. EATING JUNK FOOD

Added sugars lurk in almost every single processed food available to us, even the savory ones. “Eating or drinking 100 grams (8 tbsp.) of sugar, the equivalent of about two cans of soda, can reduce the ability of white blood cells to kill germs by forty percent,” explains Dr. Sears. The negative effects of sugar on the immune system start less than thirty minutes after consumption and may last for five hours. So you might want to rethink eating that morning donut while sitting next to your sniffling coworker. 

6. EXERCISING TOO MUCH

So far most of the things on this list were obviously negative, but exercise?! That’s right, overdoing it at the gym can be just as bad for your immune system as not exercising enough. Too much strenuous exercise can be debilitating for the body and make it more vulnerable to infection, according to a December 2012 review in Acta Clinica Croatica. But a 2014 study suggests that regular, moderate physical activity can make you less susceptible to viruses. So keep exercising during the winter, but be careful not to overdo it.

7. BEING A LONER

All this talk of contagious people might make you want to become a hermit during cold and flu season, but isolating yourself can be detrimental to your immune system. Researched published in the Journal of Neuroimmunology found that anxiety caused by loneliness actually suppresses the immune system and triggers more oxidative stress, or damage caused by free radicals. Research published in Psychological Science in February 2015 suggests that simply hugging someone can have a stress-buffering effect and reduce susceptibility to illness.