Mixing hobbies and fitness is beneficial for achieving multiple goals with the least amout of energy. Self-defense classes can be fun and raise your skill level but in and of themselves don’t necessarily increase your fitness. Mixing kickboxing with cardio, stretch and strength training can help in getting in shape while moving through martial art belts quickly.
Practicing kicks, blocks, and combinations works well for raising a heart rate. Combining this with squats, jumping jacks, burpees and other fat blasting efforts will get anyone huffing and puffing quickly. All that effort will raise the heart rate and improve fitness levels while having fun.
There is a growing body of evidence that interval training has a higher impact on weight loss and health than a consistent heart rate found in activities like jogging (1). Short bursts of energy with interval periods of rests has a high success rate. The cycle is repeated throughout the entire fitness session of 40, 50 or 60 minutes.
In experimentation I have found it is possible to cycle through kickboxing, strength training, and yoga to achieve a total body workout. For example, kickboxing offers ( kicks, punches, and combinations) to raise the heart rate, slow down that heart rate through Kata (sequenced shadow practice), raise again through strength training (push ups, squats, burpees, weights), stretch and finally strengthen through yoga.
It is a complete practice of raising the heart rate for cardio and weight loss while still increasing the strength of the body. It has the bonus of stretching muscles for maximum flexibility. All of the fitness needs are covered in each exercise session.
This doesn’t mean it works for everyone; nor that it is a perfect workout. However, there are only three types of exercise that include cardio, stretching, and strength training (2). Trying to find an appropriate sequence that maximizes the most benefits of each with the least amount of energy is something that keeps me busy and in shape. If you are going to learn self-defense you might as well get in shape at the same time.