Both the Langtang Valley Trek and the Annapurna Base Camp (ABC) Trek in Nepal are popular hiking routes, but they do have almost similar difficulty levels. A good level of fitness is required for the ABC Trek. Regular cardio exercises, such as hiking and jogging, as well as strength and endurance training, are recommended. It is advisable to acclimatize properly to the altitude by gradually ascending during the trek. As I have given tip itinerary is suitable for the trip.  Overall, both treks require a certain level of fitness and preparation. The ABC Trek involves higher altitudes and longer durations, making it slightly more challenging in terms of fitness requirements compared to the Langtang Valley Trek.