I feel very tired after lifting dumbbells, and I feel very tired the next day. Is it too much? In addition, what should be the normal reaction?

I think you're practicing a little too much. It's normal to feel tired just after training, but it can be relieved or disappeared after a short rest, but after a long time, it shows that: First, you don't exercise often, or you don't exercise properly without the guidance of a professional fitness coach; Second, if you practice for a little longer or too hard, you should keep practicing peacefully and slowly; The total time should be sustained and persistent, and the practice habit should be formed, so as to achieve good results, such as practicing 20 or 30 times each time, then stopping to relieve, and practicing again the next day and every day. After a long time, you will naturally see the effect! Fitness itself is for health. If it is caused by improper practice, it will not be worth the loss.