little,
I I've been there. I am 38 and just had my third 9 mo ago. I was soooo out of shape and miserable. When you are inactive, your muscles really stiffen up and so it feels like one fall and you're going to tear or pull muscles.
With three c-sections and very sick inactive pregnancies, I have had to start from this yucky place a few times myself.
Here is what has worked for me. Sometimes you have to get in-shape to get in shape. What I mean by that is, sometimes you just need to start somewhere very small to even be in the place where you can do normal exercise. For me with a new born, this is 5 minutes on my elliptical trainer. Really, just 5 minutes. The next time I get on it, I go 6 minutes, 7,8..until I can do 15 minutes. Also, do you have Amazon Prime? I needed to do something for my husband as well, we were both out of shape and miserable. So did a streching video from amazon prime. I needed it not to be girly so I found one that was "streching for martial arts." After about three times of doing these streches we were feeling sooo much better.
Try not to stress about being bikini ready or anything with a new born. Focus on just feeling better and more like yourself. Once you get over the hump of being really out of shape, give yourself a reasonable goal like, I will exercise for 30 min. 3x week. Then schedule that exercise time. Baby comes first, so the schedule will be loose obviously. So for me it was, on M, Tu, and Thur, I will do my work out video after I feed baby his breakfast, or after baby goes down for nap and if I can't finish it for some reason in the morning, I will finish it before dinner after kids in bed. I'm not always up for night time exercise, but it opens up one more time slot for exercise and you'd be surprised how good it feels to work out after kids are in bed. I much prefer morning exercise, but when that just does not happen, evening exercise can be a great way to make up for what just didn't get done that week. If you drink alcohol regularly, you may want to curtail that for a time, because you are far less likely to do evening exercise if you have had an evening cocktails or two.
Once you achieve a better level of fitness and baby starts to have a more predictable schedule, then up the ante. Schedule 4 workouts a week, even if you have to do half in the morning and half latter in the day. Put it in your schedule and have make up days if you get side tracked.
As for me, I don't even try to be swimsuit ready until baby eats finger foods and sleeps through the night. I find I just fail at my efforts when baby is so young and demanding.
As for types of exercise, hands down, for weight loss and least time and money invested, its running. The weight just drops when I run. I try to do 2 thirty minute runs/week, but sometimes I can only do one if my knee acts up. I also do 40 minute calisthenic/ ballet based matt work outs (hour long works outs are impossible with three little kids for me). Look into Tracy Anderson, Ballet Beautiful, Pure Barre, Lotte Burke. These are great for sculpting lean muscles. Jillian Micheals does some great hard core 30 min. workouts on DVD as well. Collect a little library and work out at home. My kids love to join me and I put out an extra matt so they can pitter around with me while i work out. They love it, and its not time away from them. It still ends up as family time. Granted it takes discipline to work out at home. Thats why you need to put it on your schedule and just do the schedule no matter if you feel up to it or not.
Also, I have an elliptical trainer at home. I also live in a temperate climate, but outdoor exercise with three little ones? Not going to happen. The elliptical is great for evening exercise while watching show, or if its too hot to run, or I just don't want to do a video.
We just sleep trained baby so now that I don't need to sleep in, my husband and I trade mornings for kid duty/ running. I run in the a.m. after I nurse the baby on M, W and husband does breakfast for the kids. Then I do breakfast and he runs on T, TH. If we miss a day F is a make up day and hopefully we work something active into the weekend. You'll get there.