Boxing doesn't come naturally to anyone, you're being hit in the head while also thrusting your hands into a solid bag and putting your muscles through hell.
If anything you're at an advantage with your karate than any other starting, you may already have trained reflexes or something (I don't know too much about karate). Keep on going definitely, it will be hard for anyone doing that. think about it, those other people doing it will have done that every week for months and years, and they will find it hard at times. It will get easier and easier while you get superbly fit and learn so much. If boxing teaches you anything, it's to never quit!
Definitely read nick chive ons answer
I used to do Ju-Jitsu and then Judo until I was 16, gym off and on in early twenties but lately decided to try boxing...it was my first main fitness activity for about 8yrs..like you it was a hour and a half, I had to stop a number of times to rest but the trainer said its okay, other boxers were trying to motivate me and offer me tips but once over I could've crawled from my car to the house when I got home and slept very well lol the next few days my legs, left arm & shoulder were aching but I knew I enjoyed it and have been back each week so far...after my third session I felt so much better I took my dog out as soon as I got in and went for a 30min run.
I still find it hard work at times but know thats a good thing for my muscles but enjoy it at the same time, everyone there is helpful also.
I now try to do 30mins skipping with a speed rope each day and do jabs with 2kg dumb bells to try to help build strength in shoulders and arms.
I would say keep it up as it does get easier each time and you do get used to each activity.
And who ever said it was going to be easy....?
Watch this for motivation
I went to a boxing class the other day after moving from shotokan karate and found it really hard..
The class was pretty advanced- everyone has a good understanding so I definitely stuck out. It was an hour and a half of almost continuous work, and I ended up having to stop before the end (we were doing things like burpys for 50 seconds, press ups for 50 seconds, bag work for 50 seconds, for about 10 minutes straight.
I found the change really really hard- I have a lot of bad habits from karate to work through, and although I really enjoyed it overall I'm not sure if I should go again..
Because I was told before I went that unlike karate, some people are natural boxers and it comes naturally, but I felt like I did crap
