The following is an excerpt from
GlobalFit - Changing lives through physical activity
Wellness Notes:
Get Results in Less Time with Interval Training
Swedes call it 'Fartlek,' which means 'Speed Play.' In any language, Interval Training is a simple, safe way to energize your workout. Best of all, it can also improve your fitness and your health in less time than currently recommended, according to new research.
What is Interval Training?
Interval Training breaks up your aerobic workout by alternating short periods (or intervals) of high-intensity activity with longer, low-intensity 'recovery' periods.
Interval Training can strengthen your heart, increase your body's aerobic ability (how it takes in and uses oxygen), and burn more calories than a regular aerobic workout. The frequent shifts also improve your body's ability to handle stress and keep you mentally alert.
How Intervals Help
Researchers tested one type of interval. Middle-aged, sedentary men and women cycled vigorously (at about 90% of their maximum heart rate) for one minute, and then they cycled easily for one minute. They performed this interval 10 times, for just 20 minutes of total exercise, three times a week.
That's just 60 minutes of exercise a week, and still, the researchers found significant heart-health benefits. Other studies have found that it helps cardiac patients (who exercised under a doctor's supervision) and helps control blood sugar, lowering your risk of type 2 diabetes.
DIY Intervals
For more experienced exercisers, Interval Training can help break past a fitness plateau. While exercise physiologists have calculated precise interval formulas for professional athletes, you can easily apply the basic principles to your own cardio workout.
▪ Warm-Up
Always do a short warm up for safe training. You'll need to be limber for the high-intensity interval.
▪ Pick Up the Pace
Whether it's walking, running, climbing, or cycling, go at a moderate rate for five minutes, accelerate for one minute, then repeat. As your fitness level progresses, you can shorten recovery time from five to three minutes.
Many treadmills and other cardio machines have built-in programs to increase intensity for short intervals; other machines can be set for manual, so you can adjust the speed, resistance, and/or incline at will.
▪ Intensity
During high-intensity intervals, you should push your limits to work and breathe harder, but not to the point of injury. Let your body tell you if it needs to go into the recovery period before your prescribed time.
The heart rate monitors on most cardio machines can help you stay in a safe, but challenging, zone.
Do It Faster
If a lack of time is what's keeping you out of the gym, then try Interval Training. With short (but focused) 20-minute sessions, you can get many of the benefits that you want.
Yes, longer sessions will burn more calories and build more muscle, but exercise shouldn't be an all-or-nothing proposition. Start with a little. Once you see results, you can then decide if you want to prioritize more time for exercise to quicken your progress.
Sources:
Gibala MJ, Little JP, Macdonald MJ, Hawley JA. Physiological adaptations to low-volume, high-intensity interval training in health and disease. Journal of Physiology. 2012 Mar 1;590(Pt 5):1077-84.
Hood MS, Little JP, Tarnopolsky MA, Myslik F, Gibala MJ. Low-volume interval training improves muscle oxidative capacity in sedentary adults. Medicine & Science in Sports & Exercise. 2011 Oct;43(10):1849-56.
You should consult your physician before beginning any exercise or diet program. GO Newsletter articles are offered as introductions to basic concepts and are not comprehensive or necessarily applicable to a particular individual's circumstances.
No, it's not New Years. No, I'm not on team two piece. No, I'm not trying to fit into a dress. Someone reason asked what I was traning for. My answer? LIFE!! My quest to lose this last 30-40 pounds is purely because I want to. 
