Chen Taijiquan

You can begin with the 5-element set which should prime you up for a slightly more rigorus training. You can also start conditining yourself by walking. Start strolling everywhere instead of taking transport and gradually increase the distance you travel. When you feel you have achieved a comfortable walking distance, increase your speed a little to a comfortable stride. Remember, the best activity is one you enjoy doing. So, learn to love whatever you are doing.