Just because it’s cold outside doesn’t mean you can’t stay warm inside — your body, that is. Certain yoga postures are specifically designed to build strength and boost circulation, and as a result, they generate some serious heat.

It might sound questionable that after holding still in these postures for only a minute or so, you’ll start to sweat as if you were climbing a StairMaster. But that’s exactly what happens. “They engage the majority of muscles simultaneously, and that’s what heats you up,” says Adrian Molina, a 10-year veteran yoga instructor who teaches his signature “Warrior Flow” at seven Equinox clubs in New York City. That’s one big reason yoga teachers return to postures throughout their classes: so your body stays warm and open. “They keep the muscles awake to allow you to get deeper into each pose and to also prevent injury,” says Molina.

Ready to get hot? Check out these three poses to get started.

Utkatasana (Chair Pose)

Stand tall with your feet firmly together, arms at your sides. Bend your knees and on an inhale, raise your arms overhead, palms facing each other. Draw your abs and lower ribs towards your spine. Exhale as you sit back further like you’re about to sit on a chair. Keep the natural curve of your lower back, while drawing in your lower abs and keeping your tailbone pointing down. (When you look down you should be able to see your toes. If you only see your knees, transfer some weight onto your heels.) Hold the pose for five breaths. Inhale as you straighten your legs and exhale as you bring your arms back to your sides.

Chaturanga Dandasana (Plank Pose)

From Downward-Facing Dog, inhale, then exhale as you move forward, so your shoulders are directly over your wrists, elbows close to your ribs. Your body should be in a straight line from the top of your head to your heels. (It’s easy to let your lower back sway toward the floor and your tailbone to poke up toward the ceiling. Stay aligned by keeping your tailbone firm and engage your abs.) As you hold the pose, your entire body should be engaged. This not only increases strength and heat, but also takes the pressure off your wrists. Protect your shoulders by focusing on rolling them back instead of forward. Hold for 30 seconds. Inhale, then exhale back to Downward-Facing Dog.

Virabhadrasana II (Warrior II Pose)

Stand with your feet hip-width apart, arms at your sides. Inhale and lift your arms above your head. Exhale and lightly step or jump your feet about four feet apart, lowering your arms to parallel, palms facing down. Your left foot should be parallel to the back edge of the mat, while the right foot points forward. Inhale as you bend your right knee over your right ankle. Use your left heel as a grounding anchor to keep you balanced and firmly rooted to the floor. As you hold this pose, your hips, shoulders, knees and ankles should all be facing forward. Stay in this pose for one to three minutes. To come out of the pose, inhale and reverse your movements. Switch sides.