Does the cold winter, with its short days and long nights, have you feeling the blues? Is your energy dragging? Do you feel like the glass is half empty? If so, you’re not alone. One in five Americans suffer from Seasonal Affective Disorder (SAD) during this time of the year.

The cause of SAD is thought to be a lack of sufficient daylight and its effect on neurotransmitter production (specifically, serotonin and dopamine) and mood. Another theory is the lack of light causes an imbalance in one’s biological clock, which controls mood, sleep and hormones. Interestingly, a common factor in people with SAD is low blood levels of vitamin D.

While the warm, long summer days are still months away, there are plenty of things you can do right now to boost your energy, mood and outlook on the day.

1. See the light.

A lack of sufficient sunlight can trigger anxiety and depression. Increasing your exposure to sunlight—taking a walk in the morning, putting your desk near an open window—can help improve depressive symptoms. If sunlight is not an option because of the weather or where you live, consider getting a light box, which simulates sunlight and helps regulate the brain chemicals that affect mood. Just 30 minutes a day under the light can significantly improve your mood.

2. Get moving.

It can be a challenge to brave the cold temperatures and go for a run or simply drive to the gym, especially when you could stay all warm and toasty under a comfy blanket. But exercise is proven to improve your mood, make you feel more positive and even boost your energy by increasing the feel-good chemicals in your brain. If you’re brave enough to take it outdoors, try snowshoeing or ice skating for a big calorie burn.

3. Practice aromatherapy.

How do you feel when you smell a batch of cookies baking? Does it make you calm and happy? Well, that’s part of the theory behind aromatherapy, which uses scents to induce certain feelings. Peppermint essential oil can be used to boost energy and mental clarity, while lavender is widely used for calming and relaxation.

4. Harness the power of music.

What’s your favorite type of music? Whether you prefer country, jazz or gospel, music has the power to lift your mood. Studies have shown that music can be used as a treatment tool for both physical and mental disorders. If you’re feeling down, crank up the tunes and sing along.

5. Let food be thy medicine.

Thanks to the wise words of Hippocrates (and, of course, a significant body of research), we know that food has therapeutic and medicinal properties. Brightly colored fruits and vegetables are full of antioxidants that can decrease inflammation and reduce one’s risk of heart disease. Complex carbohydrates, such as oatmeal and brown rice, can help your brain produce more of the neurotransmitter serotonin, which improves mood. And foods rich in omega-3 fatty acids, such as wild Alaskan salmon, are associated with reduced anxiety and depression, as well as reducing inflammation.

6. Plan a vacation.

Having something fun to look forward to may be just the thing you need when you’re feeling blue. The excitement and anticipation that comes with researching a destination and planning a new, relaxing or adventurous vacation can help make you forget that it’s cold outside.

7. Lend a helping hand.

Whether you hold the door for someone, help neighbors watch their dog, or volunteer your time to building a community garden, the act of helping someone else and putting their needs above yours will elevate your mood. Seeing someone smile or hearing words of appreciation has the power to make you feel good about yourself and forget whatever is bothering you.

8. Take your vitamins.

During the winter months, it is difficult to get enough of vitamin D (also known as the sunshine vitamin). While supplementing isn’t the same thing as actually catching some rays, it is recommended that adding a vitamin D supplement to raise blood levels should help increase the production of both dopamine and serotonin and thus improve mood. Just be sure to get your blood level checked (ask for the 25-OHD test) before starting or increasing vitamin D intake, and always consult with your doctor or a registered dietitian nutritionist before taking any supplements.

9. Get social.

After the busy social calendar of the holidays, it’s easy to feel a bit lonely with the quiet that often comes with the beginning of a new year. Having a less packed social calendar can lead to feelings of isolation and sadness. Even though you might not feel like going out, it may actually be the right prescription for lifting your mood. Call a friend and go for a walk (get some sunshine), catch a movie or plan an evening of fun with some friends at the bowling alley for some action and laughs.