The body’s natural release of endorphins is enhanced during bouts of physical activity, and this surge in happy hormones can boost your mood, increase confidence, and reduce stress levels. Regular exercise can also help improve heart health1, bone density,2 cognition3, and metabolic function4—not to mention increase muscle mass, tone, and strength. As a former Olympic sprinter, I’ve found that during stressful times, exercise has the ability to make everyday activities feel a little easier. How to: Sit on the floor with your knees slightly bent. Place your hands behind you with your fingers facing your body. Lift your butt up off the floor so that you are supported by your arms and feet. Bend your arms at the elbow until your butt touches the floor then push back up to the starting position. If you want an extra challenge: As you push up, lift your left leg and reach forward with your right arm. How to: Lie face-down and position your hands palms-down on the floor, approximately shoulder-width apart and near your shoulders. The balls of your feet should touch the ground, and your feet should be just slightly apart. Raise yourself using your arms. Make a straight line from your head to your heels and contract your abdominals to keep your hips from sagging. Lower your chest toward the floor by bending your elbows; hold for a second, then return to the start. How to: Get onto the floor on all fours. Hands should be directly under the shoulders, knees under your hips. Keep your back flat. Raise your right arm forward and your left leg back behind you. Bring your knee toward your chest as you bring your elbow to meet your knee. Do these 10 times, then switch legs. How to: Stand with feet a little wider than shoulder-width apart, hips stacked over knees, and knees over ankles. Extend arms out straight so they are parallel with the ground, palms facing down. Start by getting into a position as if you are going to sit in a chair. While the butt starts to stick out, make sure the chest and shoulders stay upright, and the back stays straight. Keep the head facing forward with eyes straight ahead for a neutral spine. The best squats are the deepest ones your mobility allows. (Optimal squat depth is when your hips sink below the knees.) Engage your core and, with your bodyweight in your heels, push back up to standing, driving through heels. How to: With your chest lifted, chin up, and abs contracted, take a big step backward with your left foot. Sink straight down so that your back knee points down toward the floor and you are putting pressure on your back left toe. Your front foot stays firm on the floor. As you push back to the starting position, lift your knee up in front of you; hold for a second, then repeat and switch legs.