The only advantage to exercising while carrying weights is that you can get more exercise while moving slowly. To strengthen your heart, you have to exercise vigorously enough to increase your heart rate at least 20 beats a minute above resting. How fast your heart beats depends on how much blood it has to pump to your body.
Sit-ups can strengthen your belly muscles, but doing them incorrectly can hurt your back. Sit-ups should be done while you lie on your back with your knees bent enough for the soles of your feet to touch the floor. Place both hands on your chest and slowly raise your head off the ground.
Elastic compression stockings have no effect whatever on exercise, according to a study from France (European Journal of Applied Physiology, July 2006). They neither increase nor decrease endurance, strength, speed, recovery, or blood flow to the limbs.