Pick activities that you find fun! Anything that gets you moving can be physical activity. You may enjoy doing something totally different from anyone else that you know and that's fine! When you are active, you want to listen to your body. If it's too easy, challenge yourself.
This can be by walking faster or with weights, adding more reps or more weight to an activity, adding another mile to your hike, or swimming extra laps. Be honest with yourself and when your activity of choice gets easy, challenge yourself to do more. There are also days that you may need to take it easier (you didn't sleep well the previous night, feel like you're coming down with a cold or sore from the last workout). Continue to move your body as planned, but take it a little easier than usual. You'll feel so much better afterward and you'll stay on track with your routine. Don't skip your physical activity unless it's absolutely necessary. If you do need to skip, make a plan of when you will next be active. You're making great progress and we want to make sure that skipping activity does not become a habit.