I got this great question in the email this morning!
Hello Patrick, ... I don't study any martial art right now but I'd like to sometime in the near future. I'm a hefty lad and in my 40's. I'm thinking of taking up judo once I drop some more weight and become a bit stronger and stretchier. Do you think this is realistic at my age and physical condition? You're about my age I believe so I thought your opinion would be worth learning. Thanks. New-to-Ju
Thanks for writing me with your question! I love helping folks out however I can.
People in their 40's (and older) start judo all the time. In fact, one of my instructors started judo when he was about 40 and was a state/regional champ by his early 40's.
I think that it is important that you shop around to find the club and instructor that best fits your personality. Look at all the judo, aikido, and BJJ schools in your area (and even karate, taichi, kungfu, etc...), go watch 2-3 classes of each, chat with the instructors and discuss your age concerns with them.
It is probably most important that you find an instructor that you like and that your personality jives with. Any martial art can be made intolerable by a jerky instructor or it can be made into an amazing experience by an amazing instructor.
Bottom line - of course you can start martial arts training when you are in your 40's!
Let me know if I can help you any more with your quest ;-)
Some additional resources related to starting a martial art in your 40's (or later) can be found right here! http://www.mokurendojo.com/search?q=older