Does rigorous and persistent study makes you physically weaker??

well i am not from this jee / neet community but my problem can be answered by you guys ..........well i am weakling i accept my body weight is just 50 kg at 5.8

but months ago I was okay with this .......now I feel so weak and exhausted internally due to long lasting study hours spending 2/3 of my day on a chair .

i don't do any physical exercise neither i play something, indoor/ outdoor nothing

so does this exhaustnes and fatigue have something to do with my prep and schedule?? or its just my weak body

my whole body is devastated, I woke up daily with pain in some new part of my body ... sometimes neck sometime arms / shoulders

i guess koi toh hoga itni badi community me jo relate kar paye 💔

kuch toh honge hi gym Jane Wale 65-70kg ke jo ayenge chidhane 😭