If you want to get in shape, you will become far more fit in far less time if you include some vigorous exercise. A new study showed that one intense exercise session plus four relaxed sessions per week improves fitness almost three times more than five relaxed exercise sessions per week (J Sports Sci Med, September 2014;13(3):702-7).
Twenty nine sedentary and out-of-shape men and women, average age 36 years, started a 12-week treadmill and stationary bicycle exercise program. They were put into one of three groups:
- Low Intensity: Five days a week of 30 minutes of exercise at 45-60 percent oxygen consumption reserve.
- High Plus Low Intensity: Four days a week of the above program plus one session of high-intensity intervals: 8 to 12 repeats of 60 second efforts at 100 percent of their maximum oxygen capacity (VO2max), with a 2.5 minute recovery between each interval.
- No Exercise at all.
Source: Fitness Empowered
Why Intense Exercise Makes You More Fit than Just Exercising
To strengthen a muscle, you have to exercise intensely enough to damage it and when it heals, it will be stronger. To have greater speed and endurance, you have to increase your ability to take in and use oxygen. You do this only with intense exercise. Whatever your level of fitness, short bouts of working at YOUR maximum will do more to make you stronger and faster than any amount of casual exercise. Athletes call these repeated short bouts of vigorous effort "Intervals".
Introducing Intervals in Your Exercise Program
Start out in your chosen activity by pedaling, walking or jogging at a slow pace for at least 10 minutes just to warm up. When you feel that your legs are ready, pick up the pace for 10 seconds and then slow down. It is irrelevant how long you take to recover for your next interval. Repeat these 10-second intervals until your legs start to feel heavy or hurt or you feel any discomfort whatever. Then quit for the day.
On the next day, you can go at a slow pace or take the day off if you are sore. The following day you can try intervals again provided that your legs feel fresh and are not sore. Repeat the 10 second intervals until your legs start to feel heavy or hurt. Continue this program of intervals and try to increase your intervals until you can sustain 30 seconds for each interval with any recovery time that feels comfortable to you. You will probably feel best with a 30-second interval followed by a one-to-two-minute recovery between each interval.
Source: NY Times
Doing intervals once a week will get you in great shape. You can do them more often but do not plan to do intervals more than every other day. Do not do intervals when your legs feel heavy or sore. Intense workouts when your muscles are sore markedly increase your chances of injuring yourself.
If You are Starting a New Exercise Program
If you have not exercised in a long time and are out-of-shape, or if you want to start a new sport, do what athletes call "Background before Peaking". Take it very easy on the first day; muscle soreness does not show up for several hours. Go out and pedal on your bike or walk or jog at a very slow and comfortable pace until your legs start to feel tired or hurt. Then stop, even if you have only done a few minutes. Do that every day until you can exercise at a slow relaxed pace for 30 minutes. Most people will take six weeks or more of this background work to be able to do 30 minutes consistently. Then you are ready to start your intervals.
Caution!
If you are out of shape, or if you are a regular exerciser but have never tried to exercise intensely, check with your doctor to make sure that you do not have a medical condition that will be aggravated by vigorous exercise. Heart attacks during exercise often occur in people who are just starting to exercise, or are making a sudden increase in the intensity or duration of exercise.
