1. Vacuum
Start by lying on your back with bent knees and arms at your sides. This workout is best done on an empty stomach. Inhale deeply and exhale through your mouth while pulling your abs toward your spine, releasing all air from your lungs. Gravity helps you here. Hold for 15 seconds, then relax. Increase the hold time up to one minute if you feel comfortable. Repeat 3 to 5 times. Each session should last at least 2 minutes. If you have stomach or health concerns, do this exercise with caution. It increases intra-abdominal pressure, which can be harmful for those with certain conditions. Avoid if you have heart issues, herniated discs, or asthma.