I used to drink heavily and got sick all the time. I got sober last year and haven't gotten sick since.

• In June, I quit drinking alcohol to improve my mental health.
• Since then, I've enjoyed clearer skin and better sleep.

I quit drinking in June in an effort to improve my mental health. I had been recently diagnosed with bipolar II, and now that I was properly medicated, I wanted to do everything in my power to reduce my debilitating mood swings.

Excessive alcohol use can exacerbate the symptoms of bipolar disorder. My psychiatrist told me that quitting would make all the difference. So I decided to go through with it, cold turkey.

It's important to note that depending on how much alcohol you're consuming on a weekly basis, quitting cold turkey can be dangerous.

In my case, I wasn't drinking enough to have to worry about withdrawal symptoms. Instead, for me, the social implications of quitting alcohol proved most difficult. I had always leaned on alcohol as a crutch for my social anxiety, so I avoided large social gatherings for the first few months. But with time and support, I began loving my sober lifestyle, as well as the blissful nights of sleep, clear skin, and more stable mood that have come along with it.

Of all the benefits, I didn't expect that quitting drinking would have such a drastic influence on my immune system.

Nearly a year later, I haven't even contracted a common cold, despite living in New York City, where people were hit especially hard by the cold, flu, and RSV this year.

I used to be perpetually sick

Before I even had my first sip of alcohol, I got sick often, frequently with the most inconvenient timing — including just before my high-school prom.

In my early 20s, when I began drinking heavily and moved to New York City, I spent more of my life sick than healthy. I came down with unknown viruses that confined me to my bed for a few days with a stuffy nose, scratchy throat, and fever.

Experts told me a confluence of factors probably contributed to this. Stress, sleep, smoking, diet, and alcohol consumption can all hamper your immune system. So when I quit drinking — and, consequently, improved other lifestyle habits, like the amount sleep I got and how much water I drank — my immune system got a huge boost.

Alcohol suppresses your immune function

Your immune system is made up of a few mechanisms that take down harmful viruses or bacteria before you can get sick. According to the Cleveland Clinic, you have immune cells throughout your body, in your bone marrow, gut, and even your skin.

When you drink alcohol, it filters through the body into your stomach, your small intestine, bloodstream, and, finally, the liver, where most of it is removed. But the more you drink, the harder your liver has to work.

Mashal Khan, an addiction psychiatrist at New York-Presbyterian Hospital, said that alcohol has an "almost corrosive" effect on the surfaces it touches as it filters through the gut, which is why people who drink heavily often develop conditions like gastritis or inflammatory bowel disease.

This also explains why alcohol consumption, even in moderation, can suppress immune function.

According to the Centers for Disease Control and Prevention, moderate drinking is one drink or less in a day for women or two drinks or less in a day for men. Heavy drinking is considered eight or more drinks a week for a woman or 15 or more drinks in a week for a man. (So, theoretically, if you're a woman and binge-drink, defined as having four or more drinks in one sitting, at least twice a week, you're engaging in heavy drinking.)

While one drink a day suppresses your immune system in a more nuanced way, heavy drinking influences it across the board, Kahn said.

Heavy drinkers are at a higher risk of developing more serious respiratory illnesses, like pneumonia, Jay Kolls, a professor at the Tulane School of Medicine, said.

"But even just one drink per day can make you more susceptible to the common cold," he said.

The type of alcohol you're consuming, your sex assigned at birth, and your genetic composition can also influence alcohol's interplay with your immune system. According to the CDC, women are more likely to suffer long-term health effects from alcohol because of biological differences.

Given that I'm a woman who was drinking two to three drinks multiple days a week, I understand now why I was perpetually sick.

Quitting drinking helped my immune system bounce back

It typically takes only a few days for your immune system to bounce back after alcohol use, Kolls said. But if you already have experienced an issue like liver damage, there's no guarantee that you'll recover fully by quitting.

I'm lucky that I hadn't experienced any major health issues, so I was feeling healthier than ever just a few weeks after quitting.

Nearly a year later, I can say that I no longer wistfully think of the days I could order fancy cocktails or bottles of wine. I'd much rather enjoy my ice-cold mocktails this summer, unbothered by the bouts of sickness that used to derail my everyday life.