When you get the hang of this exercise thing, you may find that you want more of a challenge. Instead of being satisfied with a boost in energy and a decrease in heart-disease risk, you may want to test yourself in a 5K run or a weeklong hiking tour of Canada.
Be sure to increase your training gradually; don't go longer, more often, and harder all at once. Otherwise, you really increase your chances of injuring yourself. In other words, it's not a great idea to do three 20-minute workouts one week and then jump to three 45-minute workouts the next. It's more sensible to increase the time of just one of your workouts to 25 minutes and keep the others at 20.
The best approach is to increase no more than 10 percent each week. So, if you walk 150 minutes one week, walk no more than 165 minutes the next.
Treat getting into good cardiovascular shape like a really important ongoing project. You may struggle through the first session, maybe even the first five to ten. But if you stick with it three times a week for at least six weeks, you'll start to notice dramatic changes. At that point, you'll recover much more quickly from your workouts. Instead of going home and crashing on the couch, you may feel ready to go bowling or out for a walk.
How often you need to do cardio for maximum fitness
Five days a week is a good goal to shoot for. Most people feel best with two days off a week; everyone should take at least one day of complete rest.
How long your workouts should last for maximum fitness
Depending on your sport and your goal, you probably need to mix in at least a couple long workouts — an hour or more — per week. Just make sure you don't increase the length of your workouts by more than 10 percent a week; otherwise, your risk of injury shoots pretty high.
How hard you need to push for maximum fitness
Even when you're training to get in your best shape ever, you don't want to go all-out every day. (In fact, only serious athletes peaking for an event should ever go all-out — and even then, only once or twice a week.) Your target zone includes a large range of intensity levels. On some days, stay near the bottom of the range and go for a longer workout; on other days, push harder and go for a shorter workout. Try any or all of the training techniques described in the next section.
Four ways to boost your fitness
You can play plenty of games to challenge your body. This section discusses four training techniques that you can try after about a month or two of training at 50 to 60 percent of your maximum heart rate. The less conditioning you start with, the more cautious you should be.
Interval training: With interval training, you alternate short, fairly intense spurts of exercise with periods of relatively easy exercise. For example, say you're out bicycling. After warming up for 15 minutes or so, you may try cycling all-out for 30 seconds and follow this with a few minutes of easy pedaling until your heart rate slows down a little, to about 120 or fewer beats per minute. Then you do another tough 30-second interval, and so on. In essence, you're switching between the low and high ends of your target zone.
When you first try interval training, keep the high-intensity periods short — 15 to 30 seconds. Follow these periods with at least three times as much active rest (so, 45 to 90 seconds). Active rest means that you keep moving between intervals instead of stopping dead. So after you do that 30-second bike sprint, pedal slowly for about 90 seconds. You may need even more recovery than that, especially if you're a beginner. As you become more accustomed to higher levels, you can increase the length of the high-intensity intervals as you decrease the length of the low-intensity intervals. Eventually, you can aim for a 1:1 hard-to-easy ratio, measuring intervals in terms of time or distance.
Fartlek: This charming word means "speed play" in Swedish. Fartlek is basically interval training without an exact measure of time or distance. You just do your intervals whenever you feel like it. You may try sprinting to every other telephone pole. Or set your sights on that horse standing in the field down the road and pick up your pace until you reach him.
Uphill battles: You can add hills to walking, biking, running, or skating workouts. You have to work harder when you come to a hill, but ultimately you're rewarded with extra strength and stamina. As a bonus, going uphill can burn twice as many calories as exercising on flat land. One fun drill is to do hill repeats. Find a long, fairly steep hill and then sprint up it and jog down it, repeating this sequence four to eight times.
Here's a trick to make hill workouts seem easier: Pick a landmark that's partway up the hill, such as a bush or mailbox. Pretend that you have a rope in your hands and cast it over your landmark. Now pull yourself up the hill with your imaginary rope. When you reach your landmark, cast your rope on something farther up the hill and keep doing this until you reach the top.
Tempo workouts:Tempo workouts help you learn to move faster. During a tempo drill, you move at a pace that you consider challenging but not brutal, keeping that pace for four to ten minutes. Do that a couple of times each workout. In between, exercise at your normal pace. If you're new to tempo training, begin with short tempos and gradually increase their length. Anyone training for a local road race or a bike-a-thon will find tempo work helpful.
Training for a specific event
Thinking of training for a 5K or 10K race, half-marathon, century bike ride, or triathlon? Ideally, you want to spend at least 16 weeks (about 4 months) preparing for your event. Take the first six to ten weeks just getting used to running, cycling, swimming, and so on, slowly building your weekly mileage at 10 percent each week. Starting at about 9 to 11 weeks, begin using the techniques listed in the "Four ways to boost your fitness" section, mixing them into your routine. For example, one week, you might do uphill training one day; the next week, you might try a tempo workout on a Monday and a fartlek on a Thursday. In between, you run, cycle, or swim at a more moderate pace or take a day off, allowing your body time to recover before your next workout. By 16 weeks, you should be ready for the big day.