Need your oppinions if I have a problem or not.

Thank you for the brief analysis, sure, there might be something wrong with the measurement tool. Maybe I ll try to do measurements with an hr belt.

As for what I do during my practices, here is the hr graph from the last badminton practice. First 4 peaks are intervals. 4 mins acceleration, 2 mins walk (4 times). Acceleration is 4 min/km. And all the rest is multishuttle feeding on court. So, you can see, that during these 4 moderate accelerations hr was about 160 and I felt myself like I’m flying, no breathing problems, no muscle tension, nothing. But during badminton practice I felt completely exhausted many times although hr was about 100. And I do not understand why is it so. It should be vice versa, no?