Sunday my husband and I went for a hike. Monday I did some work outside. It has been in the 60's, probably the last time we will see such high temps for about five months. Alot of people struggle to get enough exercise when the weather is cold and ugly out. I am lucky in that my town has a natatorium with indoor pools, exercise equipment, classes, etc. that is fairly reasonably priced. If joining a gym is not an option for you, either because of unavailability, lack of funds, or other reason, there are still plenty of ways to get exercise in the winter.
Many people find outdoor sports invigorating- hiking, ice skating, skiing, etc. Not me. I hike outside some in the winter, but my body reacts to the combination of cold and damp (such as sweating)- by developing hives. They do go away soon after I am warm and dry, but can be uncomfortable while I have them.
Most malls open early for walkers. My mom used to meet friends at the mall, walk for 45 minutes, then go out for coffee. Exercise and a social outing combined. Actually, pairing exercise with social opportunity makes it more likely you will follow through.
Some people have a hard time getting out of the house, especially when it is cold, snowy, icy, etc. Sorry- that's no excuse. There are still many ways to exercise at home. There are hundreds, if not thousands of DVDs and videos that guide you through an exercise routine. Try getting some from the library to see if you like the style and level of the routine. Another option related to this is You Tube. Try searching for 'exercise' for a variety, or for a specific type such as 'yoga' to narrow down the list. There are videos of single exercises, as well as whole routines. Try searching the internet for a type of exercise you like. There are many sites that demo exercises you can follow. Just remember that anybody can make a video or website. Just because it is available and has the right title doesn't make it good or even safe. Use your judgment. If something doesn't look compatible to your ability or interest, skip it.
Pun intended there- Skipping is excellent exercise. You can skip up and down a hallway, around a room, with or without a jump rope. You probably will want to make sure there is enough clearance for the jump rope, if you choose that option. You can walk around your home. Set up a course of furniture to go around, in and out of rooms. If you have stairs, going up and down is excellent exercise. You can get an exercise step, or a sturdy, stable step stool to step up and down on.
There are a variety of exercise machines that you can buy, but it is a good idea to do some research before you buy. A type of equipment that one person really likes may cause pain for another person. If you can, try out different equipment at a gym before you buy. Unless you are rich and have a large home, it would be a shame to buy something that doesn't work for you, and end up with an expensive, massive, ugly clothes hanger in the middle of your room.
I have a Wii, and the program Dance, Dance Revolution. It is a fun way to exercise on days I don't want to go out into the elephants (or, as most people call them, the elements). There is also Wii Fit, with a variety of exercise and health related programs. Some other game consoles have exercise related programs as well.
To exercise your arms, you can get small weights or even cans of soup to lift, or Thereband or other stretchy material to pull on. Videos, You Tube, or other online sites can show you what to do with them. You can do wall push ups, or other pushing, pulling, lifting activities. Think about how you use your body, and avoid actions that aggravate your pain.
I believe exercise is important for everyone, no matter your ability or disability. If you have something that limits how much you can exercise, it is still important to stretch and to move your muscles and joints around. This can help to keep you as flexible as possible, to make bathing, dressing, etc. easier, and can even decrease pain.
This list covers a variety of options, but I am sure there are other options that I did not think of. Experience, combined with common sense (and, if needed, input from your doctor and/or physical therapist) will tell you what level and type of exercise is right for you. A general goal for most people is to start where you are, and slowly increase your strength and endurance. It is good to have a variety of things you do, so that you can alternate cardio with strengthening, and vary which muscles you use. It can also be helpful to have choices for different moods or for days you have more or less energy or pain, or just to have enough variety so you don't get bored.