Hill sprints are the absolute best exercise to lose weight, maintain a trim body and just feel GREAT no matter what age you are!  Introduce them into your regular exercise program.  For example, if you hit the gym or work out at home on Monday, Wednesday and Fridays, do your hill sprinting on Tuesdays and Saturdays. 

If you've just started an exercise program, I'd suggest you do your hill sprinting by walking up stairs or stadium steps.  Or you can do a fast walk up the hill that you have as a goal to conquer with the sprinting.

- If your hill is reasonably close to your house, consider walking or jogging to the hill as a warm-up, and walking/jogging back to your home as a cool-down.  The best hill's to start on are NOT steep ones, but one that is a gentle slope up.  If it's a great hill but short, then start about ten yards from it and run the ten yards or so up it.  You'll get the hang of it in no time!  

I strongly suggest you do hill sprints at least once per week and no more than twice per week because your body really needs the recovery time.  Be your own judge on that, but if you start to get aches and pains that don't go away, more tired than usual, rough time sleeping... then you've overdone it.  Give your body a week's rest before you start back up and even then do it just one time a week until you feel you can get back to doing the hill sprints twice a week.

- If you find your sprinting surface tends to be slick, pick up a pair of soccer cleats at your local sports wear store.

- Gauge your optimal sprint distance based on whatever hill(s) you've got access to. If you've got access to two or more hills, employ a "short sprint" workout and a "long sprint" workout each week.

- Use a stopwatch to time your sprints. If/when your speed declines by 10% or more; discontinue the sprints for that day.

Hill sprinting is by far one of the most fun, effective, and practical methods for losing excessive fat weight, improving your total body speed and power along with being a very potent stimulus for rapid body composition changes (reduced body fat %).

Here are some reasons for putting this powerful training method into your overall program:

Safety
Due to the inclined surface, maximum limb speed cannot be attained and thus serves as a safety barrier for your hamstrings. Your posterior muscles (low-back, glutes, hamstrings and calves) get an incredible strengthening effect.

Self-Discipline
Unlike almost any other form of training, that hill has a way of making you work hard.  Once you've got your momentum up, you won't want to lose it, so you're actually compelled to maintain or even increase your speed.  

Weight Loss Hill sprints are probably the best way to dramatically increase the caloric expenditure. This has amazing benefits on your body composition!  You will lose the weight that has been so difficult to “exercise” off.

Technique
Because of the inclined surface, you are forced to lean forward as you sprint. Hill sprints actually become your sprint coach because you almost can't help but do it right!   Hills sprints also teach aggressive arm and shoulder action, which is so critical for maximal acceleration. You simply cannot sprint fast up a hill without deliberate arm action.

Efficiency
Hill sprints offer great multitasking potential. You can train, catch some sunrays and soak up that Vitamin D, and listen to your favorite tunes while you train.  Make sure you take your water bottle(s) with you!

Don't approach hill sprinting unprepared.   Be sure you warm up by stretching your legs, back, shoulders, and arms.  Then take a few minutes to do two "get ready" sprints at about 25% of what you feel would be your maximum speed for that day.   Here's an example of how you approach sprinting the hill.