Warm your body & mind up to the idea of exercise. If you haven’t been physically active for a while, it is best to start slow.
Try a light work-out then see how your body feels the next day. Listen to your body during & after exercise & it will tell you if you are working at a good level of exertion.
What is a good level of exertion? If your level of exertion is too easy, you won’t get results. You should be working at level that you feel challenged, at least a little bit. As your body conditions/adapts to the demands that you put on it, challenge yourself a little more.
A moderate to challenging level of exertion is best. Find a pace that you can comfortably maintain. You should be enjoying your experience.
Learn to self monitor (how you feel). If you are challenging your self too much, slow down. You should be warm, have a slight bead of sweat on your brow & a spring in your step.
To maintain a good pace, try listening to upbeat music (motivating & more fun). Exercising with friends or with a personal trainer can help, if you need an added challenge
Extreme levels of exertion aren't recommended. If you do too much, burn-out & injuries are likely. No pain, no gain is a myth. Pain does not motivate me to exercise.
If you are not sure how much is too much, try using the Talk Test (I use it all the time, to make sure that I am in the best & safest heart training zone).
1) Too Easy = you are able to sing, while exercising (therefore, not exercising hard enough).
2) Moderate level of exertion = you should be puffing a bit but still be able to talk (this is best)
3) Too Hard = breathing is difficult & unable to have a conversation
Throughout history, the Borg Rating of Perceived Exertion has also been used (the scale goes from 1 – 20: http://www.doctorsexercise.com/journal/borg.htm). A simpler, version of this scale:
1 = too easy
2 = a bit challenging
3 = challenging
4 = very challenging
5 = too much
Remember, listen to your body after exercise as well (the next day for example). If you wake up too sore, perhaps you did a little too much too soon. Adjust your level of exertion accordingly.
If your body needs a rest day, take it. A rest is just as good as a work-out (for muscle recovery). I think our brains need this as well. I have been burned-out from work. We need to try to find a balance.
Be realistic. We are all different. Don’t try to keep up with someone else. Pace Yourself. Be proud of what you can do & that you are improving your health. Keep it up & you'll make great strides!