If you’ve been feeling a little gloomy lately, you can probably blame at least some of those emotional doldrums on the winter season.

There’s no doubt about it – seasonal affective disorder (SAD) is real, and it impacts many Americans during the winter months. As a result of less sunlight, your body will naturally produce less serotonin, which is a mood-enhancing chemical that regulates hunger and feelings of self-worth. Put simply, less serotonin is bad news.

Top that off with shorter days and a lack of natural light (which can throw off your internal clock) and you might be feeling sad because your body is literally out-of-sync.

The symptoms of SAD can include depression, low self-esteem, irritability, shyness, panic attacks, worry over little things, and an increased level of sleeping. Even if your winter lows are mild, there are simple changes that you can make to lift your spirits, right now, for free.

So let’s get started.

First, get moving.

Although your motivation to move can drop in the winter (because who wants to run on a treadmill instead of outside?), exercise is especially important in the winter. That’s because exercise releases serotonin in the brain, and you need all the serotonin boosts that you can get. So take your lunch break and walk the halls or look up some yoga routines online – do whatever you have to do to keep some movement in your day. (Also, talk a significant other or friend into giving you a massage – this will also release serotonin in your brain.)

Next, eat (and drink) mindfully.

Another way to get at more serotonin is through sensible carbs, which prompt your body to produce it. Sweets, white rice, and white bread are examples of empty carbs that will only serve to raise your blood sugar, which floods you with insulin and subsequently drops your mood. Since you want to give your body a helping hand and not a kick in the butt, pass on those foods and make it a cold weather goal to eat better.

Then, start a project.

You’re stuck inside because the outdoor air is frigid, so you might as well use your time wisely. There is only so much moping around and watching CSI reruns that you can (or should) do. Get yourself motivated to de-clutter, clean out desk drawers, organize your closet, knit a sweater, or tackle another DIY project. The sense of accomplishment you’ll get will distract you from stress and the winter blues.

But also, give back.

If organizing your living space doesn’t strike a chord of motivation, then go find a sense of purpose by giving your time to something you love. Giving back to your family, friends, community, or a cause you hold dear will help keep your focus on what matters most. And while you’re busy being focused on uplifting others, spring will arrive!