Starting a new routine .

Congrats on deciding to change things. The easiest and cheapest way to try different workouts for me has been youtube. Search "befit" and a lot of different workouts come up. Most of them you can do in your home with little or no equipment. Good Luck!

If I could encourage you to start a beginner weight lifting routine. Just 3 days a week. Why?

Lifting weights is KEY. I recently had my DXA scan done and at 51.5 years of age I have the bone density of a super athletic 30 year old. That is a direct result of lifting for over 30 years. Now if that is not scientific proof that lifting weights keeps you younger I don't know what is! Also I believe it is why most people think I look much younger than I really am.

Girls, start lifting now. lift heavy and change it up often, find a lot of weight routines with free weights, make it fun, embrace it, make it part of your life. Only 3 days a week is all it would take. Crank up your tunes and learn to love it, because your body will love it and it will make your quality of life better in many ways, especially when you get older like me.

Because of this I don't have to worry about osteoporosis. If you wait until you are older and your bones start to deteriorate it's a bit too late, you can't get back what you lost, you can only start a resistance routine that will prevent further damage.

f you are a girl you don't have the hormones to get big naturally. I lift heavy and I'm still really tiny. My lean body mass is only 104 lbs and that is fairly heavy for a 5'1" female, and quite a bit of this is due to my having very dense bones from 30 years of lifting, not all muscle, and I'm still quite tiny.

My muscles really are not that big, but they show a lot of definition because I'm quite lean. If I gained some fat then I would have a softer more toned look (which is OKAY too!). Then if I gained more fat I would look bulking and hefty like I did most of my life until last year. YOU CAN HAVE WHATEVER YOU WANT. Lean and ripped, soft and toned, or hefty, it all depends on how much fat you leave on your body. Calories are the only thing that change fat. Exercise is for changing or maintaining your lean body mass only. Lifting weights will give you the best bang for your buck for shaping your body. I finally changed my shape by putting lifting first and cardio 2nd. You can not out exercise too many calories. I learned this the hard way ---> http://www.myfitnesspal.com/topics/show/740340-i-lost-60-lbs-at-age-51-anyone-can-any-workout

Since you don't have any equipment. I would suggest body weight strength exercises to add to your cardio. (And if you could change cardio up a bit with swimming and bicycling, it would help keep you from getting bored.)

Pushups
Planks
"Air" Squats
Walking or stationary lunges
Yoga (Sun salutation full asana)
Calf raises (using a step)

If you can incorporate weight training, I would strongly recommend it. Building lean muscle mass will most certainly help.