Looking across the fitness and health world, you will find a great many kinds of exercises that you can do to feel better and become healthier as you get in better shape. There is perhaps no better method to train than using the interval training technique. I often tell my students that exercising is a simple two-step process: (1) get started on a program of your choice and (2) slowly increase your intensity. Choosing a good time to exercise and what to do can be well, a chore. Here’s a suggestion – if you have not exercised for a while begin by simply walking.

Choose from 1-3 miles per day initially and just enjoy being outside. Once you’ve been walking for a week or so, slowly begin increasing your intensity. What is intensity? Simply put, it is the level at which you work out. To increase your intensity in walking, you would want to walk the same distance in less time than the last time you walked. This is a way to judge your personal improvement. However, you do not need to walk fast the entire mile, you can walk faster for shorter distances. For example, suppose you’ve done your walking program for a couple of weeks. On the third week, walk the first half mile at your normal pace then, walk a quarter mile perhaps 30% faster then, slow back down to your normal pace for the remainder of the mile. You can repeat this process as your fitness level allows. So, what you’re doing is walk normal, speed up quite a bit for a short distance, slow back down to your normal pace, speed up again, and so forth. As you speed up your walk you automatically increase your intensity.

Speeding up and slowing down is called interval training and though applied to many aerobic exercises in the gym, as well as running, rowing, martial arts, speed-strength and more, it is especially beneficial as you begin to increase your cardiovascular endurance. And, beginning your first program, especially if you have not exercised for some time, it will give you greater control over your heart rate and breathing.

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A more proper definition of interval training is that it is a type of training that involves a series of low- to high-intensity exercise workouts. These workouts, as described for walking above, are interspersed with rest or relief periods, i.e., the slowing back down to a normal walk. The high-intensity periods generally approach a level that corresponds to anaerobic exercise or close to it, while the recovery periods (slowing down your walk or stopping the activity for a short period) involve activity of lower intensity. Why would we want to do interval training? Interval training strengthens the heart and helps build cardiovascular fitness with shorter workouts

Almost anyone can do interval training. But, be sure to check with your physician to see if it is right for you. If you have a physical ailment or heart condition, because you are alternating between short bursts of intense exercise and brief periods of rest (or a different, less-intense activity), your exercises could affect you more than you may think. If you can perform interval training exercise, your reward will be improved cardiovascular fitness. Often, we think of only aerobic exercises as cardiovascular training but, depending on how you perform your chosen exercise, almost any exercise you do will help build a healthier heart and improved circulatory system.

However, no matter what kind of exercise you perform, if you are not already doing so, a good regimen of aerobic exercise combined with current exercise(s) is essential to good health. This means biking, jogging, rowing, etc. Give interval training a trial run simply by altering your current workout routine as discussed in walking above or jogging or similar exercise (some tips are below). To get a good cardiac boost from interval training, you need to be willing to push yourself close to your limits—at least briefly. This means staying in a training zone and knowing what those limits are. Duration wise, three, 20-minute sessions per week of interval training could add gusto to your exercise regimen and enhance your cardiovascular fitness.

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Some Guidelines General medical guidelines advise individuals to perform about 2 ½ hours (150 minutes) per week of moderate-intensity exercise. To do this, you need to find a time to exercise, which typically will include 5 days at 30 minutes per day. The walking explained above, to get started, is a good beginning, but you need to build up to a brisk pace, which would be considered moderate. A brisk walking pace is about 100 steps per minute or 17 minutes per mile – note the average mile pace is 20 minutes.

I recommend a 15 minute per mile pace as a brisk pace. Regardless of the activity, if you raise your heart rate, that is what is important. Once you can walk then, you can begin jogging, swimming and so forth at a more rapid pace. In doing so, you will continually improve your cardiovascular fitness and likely your overall health as well. Research I’ve conducted with athletes suggest that instead of 2.5 hours per week, you can accomplish the same with 1.25 hours per week by utilizing higher-intensity exercise. However, this involves more than the beginning walking program described above.

You will likely have a see-saw relationship between exercise intensity and duration. This is good, because it is what makes interval training work; but make no mistake, for it to work properly you will need to work up a sweat. The rule of thumb for high-intensity implies being able to exercise at a higher intensity or velocity than you could otherwise sustain for five to 10 minutes before becoming exhausted – a good exercise example is roller blading. Thus, for interval training, you perform high-intensity exercise for a minute, then rest, then repeat.

This often develops a love-hate relationship for interval training. While some will find such training invigorating as he or she pushes to individual limits, others will find the training unpleasant. Consequently, choose an exercise you really enjoy before trying it full steam. Personally, I’m a speed sprinter and I love it; it’s a perfect interval training exercise – anaerobic. In the end, however, you don’t need to stick to interval training all the time – just try it occasionally to shock your system. You can, for example, do interval training on one day and switch the next day to longer-duration, moderate-intensity exercise.

Tips to Adapt Interval Training to your Workout

Gym equipment/machines.
Treadmills, elliptical trainers, and stationary bikes often have a built-in interval training function to put you through your paces – try some of the built-in programs to determine which suit you best. Swimming. If using an Olympic size pool, swim one lap as fast as you can. Rest for about the same time as it took you to swim the lap. Repeat. If using a smaller pool, swim two laps as fast as you can, rest as above and repeat.

Walking.
Walk as fast as you can for two minutes (this assumes you are in okay shape). Then, walk at your normal pace for 2 minutes. Repeat.

Jogging.
Jog for 3 minutes at your normal pace then, double your speed for 1 minute. Repeat, alternating jogging and running until you complete your distance. Speed Sprints. Choose a distance such as 40, 60 or 80 yards. Sprint full speed. Rest for 15, 20, and 30 seconds respective to distance. Repeat for 8, 6, or 4 reps respectively.

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The Benefits
Simply put, interval training allows you to accomplish the same amount of exercise or work performed in less time. Generally, interval training can reduce your required time of 30 minutes of exercise per day to 15-20 minutes. If you have a particularly busy day then, interval training can allow you to do your exercises without cramping your time. This can make workouts easier to fit into a busy day or open a time slot to add some extra resistance training. If you reduce your moderate 30-minute workout to 15 or 20 minutes of interval training, the cardiovascular benefit should be about the same. This is part of the appeal for speed-strength and cross-fit exercises. With improved fitness comes an increased feeling of wellness. You should feel better, with greater endurance and, as the adage states, feel more get-up-and-go.

Something important to remember however, is that cardiovascular training does not significantly boost muscle strength or power. For example, marathoners do not have the unusually strong leg muscles that track and field athletes have but, their hearts and lungs work together at peak performance. No matter what type of cardiovascular training you choose, you must do it regularly to notice the improvements. Further, three days per week is the minimum; greater performance ability requires more!

Safety First
If you’re generally healthy, interval training should not present major risks, if you do not begin too fast. So, if you have not done this before, begin slowly. As the exercise becomes easier, you can increase intensity. As always, the recommendation is to consult with your physician before beginning such exercises. This is important if you have heart disease or high blood pressure. Talk to your doctor before starting interval training or any other new exercise program—especially if you have been relatively inactive. As with any exercise regimen, reduce the risk of straining a muscle or joint by starting each day with a gentle warm-up before your workout to loosen joints and increase blood flow.

Generally, with such exercises you should be prepared to feel the burn and you may be slightly sore for a day or so after the first interval training challenge. If you are really sore, you overdid it so, slow down – the gym isn’t going anywhere. Also, after each day, perform some warm-down exercises; this will help to reduce soreness that may derive from your training, as well as help relax you before you leave the gym. Rest from exercise is also important – be sure to rest at least one day per week.

Avoid Over-stress:Get into your Aerobic Zone
Every aerobic exercise performed at moderate and higher intensity will get your lungs and heart pumping to deliver the oxygen to muscles, i.e., cells within your muscles. This oxygen is used to help produce energy. Use the following diagram (courtesy Wikidoc), determine your best heart rate to find the level of exercise that gets you in the aerobic zone and enhance your cardiovascular fitness.

Generally, you would subtract your age from 220 to roughly approximate your maximum heart rate during exercise. As a rule of thumb, exercising at between 60% and 70% of your estimated maximum heart rate is sufficient to build cardiovascular fitness. If you can gradually condition your way up to 80%, the fitness gains will be even more noticeable. And, thanks to technology, using a wearable heart rate monitor can help you stay in the aerobic zone and show the benefits as your fitness level improves.