While you don't get the change of scenery of an outdoor walk, you can use a treadmill rain or shine, and using the machine is easier on joints than walking on concrete or asphalt.
To use the treadmill safely, start with one foot on each side of the treadmill belt - there are foot rails for this purpose. When you're sure that the machine is on at a low speed, step onto the belt. Once you're on the belt, adjust speed and incline as necessary.
Keep your eyes straight ahead when you walk. Your feet tend to follow your line of sight, and if you look behind you or to your side you could stumble off the machine.
Know where the emergency stop button is, and don't be afraid to use it if you feel as if you're going to fall. Some treadmill models have safety keys that attach to a strap - you clip the strap to your clothes, and if you fall or trip, the key comes out of the machine and automatically stops the belt.
Ask for help. If you're at the gym and need assistance, don't feel shy about asking a gym attendant. At home, the instruction booklet should have information on treadmill functions and safe use. It may also include a company phone number for questions.
If burning calories is your goal, the most common mistake you can make is grabbing the handrails. The first few times you use the treadmill, you may need to hold the handrails, but don't continue holding them unless it's necessary for balance - it drastically lowers how much energy you expend.
And, as you repeat the same series of exercises week after week, your body adapts to the pattern, making exercise less challenging. To ensure you're getting the most from your workout, mix up your routine by changing your speed and incline. Most treadmills have several pre-programmed exercise routines to choose from.
Source: Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50