In one sentence, describe what the following article is about:

If you currently exercise in the afternoon or evening, consider changing your exercise routine to the morning hours.  Some studies have shown that morning workouts boost your body's ability to burn calories from stored fat instead of using calories you've consume through food during the day.  Schedule workouts for 20 to 30 minutes after you wake up. In addition, getting up in the morning will help ensure you don't get too busy or tired during the day and then skip a workout later on. Changing up your routine can be difficult at first. But after a couple days of getting up earlier (and going to bed a little earlier), you'll be just fine with your new AM routine. HIIT workouts are popular these days and for good reason. Studies have shown they help burn more fat and keep your metabolism elevated longer than traditional exercise.  Typical HIIT workouts alternate between bursts of very high intensity exercise (like sprinting) and bouts of more moderate intensity exercise (like jogging). Include one to two days of HIIT workouts each week. Perform 45 minutes of cardio with a 10 minute warm up and 10 minute cool down. The 25 minutes in between should be devoted to sprinting for 30 seconds to one minute and returning to moderate intensity for two to four minutes. HIIT boosts the production of the human growth hormone by 450 percent for 24 hours. It helps you lose fat rather than muscle, so it is ideal for weight loss. High-intensity is 80 to 85 percent of your maximum heart rate. You cannot keep up a conversation and you get extremely “winded.” Moderate-intensity is 65 to 80 percent of maximum heart rate. You can keep up a conversation with a friend, but are short of breath. Alternate between these two. On alternating days where you are not doing a HIIT workout, include some strength training. Keep in mind that it takes a while to build muscle. However, regular weight training along with a healthy diet can help you to build muscle mass over the course of four to 12 weeks, which will boost your metabolism.   Strength training exercises help you build lean muscle mass. The more lean muscle mass you have, the higher your metabolism will be.  Start your week with popular exercises like bicep curls, tricep presses, chest presses, rows, squats, lunges, and calf raises. These are quick to do and can be easily incorporated into your current exercise routine. Try new weight machines, kettle bells or TRX straps as well. Better yet, work out with a friend or personal trainer who can show you how to use new equipment. Work to the burn for 12 to 15 reps. Do two to three sets. In addition to HIIT and strength training workouts, include a few days of other types of cardiovascular activity. These types of exercises also help support weight loss.  Like HIIT, cardio also burns a significant amount of calories per session. Include 150 to 300 minutes of cardio exercises each week (HIIT can count towards this as well).  Other activities can include: jogging/running, using the elliptical, dancing, swimming or taking an aerobics class. One of the main differentiating points of cardio and HIIT, is that these cardio exercises are done at a constant, moderate intensity and not alternating between high and moderate intensity levels.

Summary:
Work out in the morning. Do high-intensity interval training (HIIT). Start weight training. Include other forms of cardio.