How old is to old

You aren't necessarily too old of the activities they are doing, you just aren't used to doing them. So instead of killing yourself, work your way up to it. Age is just a number and if you let that hold you back, you'll never get to where you want to be.
Ease yourself into things. Instead of 2 classes, start with one. Do that for a month, 2 months if you have to, and THEN add in the second class. If you can't do the full 30 minute spin class, do 15 minutes, and work your way up to it! Before you know it, you'll be running circles around these women in their 30's!
I have confidence! Don't let your age hold you back!

You are definitely not too old. I met this guy on Sunday doing a Triathlon literally blind and he is 73 years old.

Go easy on yourself. Just hang in there you can do it!

An hour and a half straight and you wonder why you're tired!? You should be exhausted after all that!

Just because we can't keep up with the "kids" is no reason to NOT exercise. We just need to take it a little easier if we can't hang with the young 'uns! Try something a little less high impact. That doesn't mean you can't work up a good sweat, just take it easier on your joints and don't go at it so hard you can't breathe!

I'm 54, with bad knees. I do water exercise 3x a week for about an hour and stationary cycling 2 or 3x a week for about 30 to 45 minutes. I've stopped logging it as I've been slacking off due to knee pain. Swimming is also excellent if you have access to a pool. Pilates is good if you can still bend that way, as is yoga. Yoga is a no-no for me with an artificial hip. Lifting weights is good too.

I am 28 and I would have been dying if I wasn't used to all that exercise. I could barely get through a 30 min (30 Day Shred) Video! I agree with some of the comments above, you need to work your way into it. If you think you can just get up and work out like a maniac, you are setting yourself up to fail. Don't give yourself a reason to not go back. Get back on the horse and try a 30 min work out for a few weeks, than move up. You will know when you are ready. You can do it! Age is nothing but a number, you will get to where you want to be. Great step being on MFP! Good Luck! You can do it!

Good for you for getting out there and exercising! I am 36, and this past 3 weeks has been PAINFUL! But honestly, now I'm starting to feel the benefits of added energy and better sleep and it's awesome. And, I may deny I ever said this, but I honestly can't wait to go exercise.

My mother is almost 70 and just started going to the gym for the first time in her life about 2 years ago. She consulted with the personal trainer for her free consultations and it's helped her greatly. She mostly does weights and cardio equipment, but hasn't tried the classes yet. But she's a killer on the elliptical now! When she started out, she was very sore and tired and couldn't do a lot. But she kept at it, and has built up her strength and endurance. It takes time, but it's worth it.

You can do it! Mix your days up with some lighter activity so you're feeling more balanced and have time to recover.

You aren't necessarily too old of the activities they are doing, you just aren't used to doing them.

^THIS^

It has more to do with being out of shape then it does being 59. I know 60 year olds who can run circles around me! Keep working out and you will be keeping up with your classes in no time!

*also, I'm with the girl above that you may be doing too much high intensity cardio. Maybe look into getting a personal trainer?

You can do anything the younger ones do. Maybe just not as fast or as much. You just do what you feel comfortable doing and you will work up to doing more! I think you are doing great in what you have done.

You're never too old to be healthier - and look at all of the progress you've already made! 23 pounds is worth celebrating, whether you're keeping up with a 30yo or not

This!!!

I see a lot older ladies in my gym, surprised they do not come in on walkers !!. My mum still goes and she is well into her eighties (or so it is rumored).

Even at my age (45) and male I find it hard to keep up with some die-hards in the gym and I do love to thrash myself.

The good new is this. You just do not need to go that hard to get results. In fact by cutting back to one 20 minute sessions a day (at least 3 times a week) will get good results (if you can do it properly). The trick (well published apparently) is to go hard for 20 seconds and then easy for 10 seconds for the full 20 minutes. It is really hard at first but the idea is to get your heart rate up and then rest to let it drop. With these times your body rests but (I find) your heart rate stays high and that is what get your results. The way to judge it is the 20 seconds really hard you should be able to make ... just, the 10 seconds rest is to keep you moving (do not stop).

You can laugh at all your colleagues (if you have a nasty streak) that they go to multiple classes and you get better results just popping in for a quick 20 mins.

PLEASE NOTE: I am not a professional, I did get this information from a professional and I suggest you do the same. This has worked for me in the past (I was doing it a little differently), but I am now on a totally different program (eat more, do less) and I am shedding weight 1 week in.