There are no limits to what our body can do, no limits except those that we make ourselves. This is especially visible in the area of physical activity. One extremity would be bodybuilding with the muscle mass bulked up to the maximum and even more, and the other extremity leans towards the overall perfect shape and the ability to perform greatly in many different physical activities (decathlon is a perfect example).
Types of workout
Both extreme activities require a lot of effort, and some supplements. Which side will be chosen depends on a personal affinity, although it can be said that having a bulked up body might not be as healthy as having a fit and slim body with lean and also strong muscles. Besides that, cardiovascular exercises are much better for overall health of heart and blood vessels than exercises generally used by bodybuilders. There is also some sort of middle way, so-called body fitness, which emphasizes fit body with strong muscles, not as large as in bodybuilders, but much bigger than in those who do only cardiovascular exercises.
When it comes to cardio workout, there is one that might prove to be very effective and can create both strong and fit body. It is military boot camp workout with the main characteristic of fast change of rhythm and fast change of exercises which are, of course, executed as quickly as possible. Exercises included are squat thrusts, push-ups, jumping jacks with or without added kicks, abs exercises, back exercises, etc. The point really is in doing all those as fast as possible with about 10 repetitions in each exercise.
Military boot camp workout should not last for long, especially if it is done properly, which means quickly and regularly. Workout has to include warming up with running in place or walking and stretching at the end in order to prevent some muscle, tendon, ligament or joint injury.
Also, only exercises are not enough if some caution is not focused on meals. All calories spent for workout can be easily regained if meals are not adequate. Basic tip here would be to eat as often as possible with small amounts of food. Also, meals should contain enough nutrients to cover the basic needs of the body and some extra more, because of the exercises. Intake of calories should be reduced if we want to lose weight faster. Supplements for fat burning are allowed, and also muscle gainers, but only to certain point. Using muscle gainers intensively and lifting weights might lead to bodybuilding.