10-Week Workout Routine: How Hard Should You Exercise?

A reader writes that he's going to participate in the 10-Week Workout Routine but has a question: When it comes to aerobic exercise, how hard should he be working out? I asked for advice from Vonda Wright, the orthopedic surgeon who designed the routine (and author of Fitness After 40: How to Stay Strong at Any Age).

If you're a newcomer to working out, she says, you probably can start with a very simple "talk test": While you're exercising, can you have a conversation made up of single sentences? Your effort level shouldn't allow you recite one of Hamlet's soliloquies, but you should be able to ask your walking buddy's opinion about Lindsay Lohan's latest antics. That level qualifies as brisk exercise, says Wright, and it's what the government means when it recommends 150 minutes of moderate aerobic exercise per week.

If you're a numbers person, Wright says you can go by heart rate. To measure yours, stop or slow down your workout and immediately put your fingertips lightly on the pulse points either at your neck or wrist. Count how many beats you feel in six seconds, add a zero, and you have the number of times your heart beats per minute.

To find what the heart rate should be for a good aerobic workout, the rough formula is to subtract your age from 220 to get your maximum rate, and then aim to work out at 70 to 80 percent of that. So if you're 45, your approximate maximum heart rate is 175, and your target aerobic zone is between 123 and 140. This isn't an exact range, Wright warns, but it's a good starting point. If you'd prefer to have a gadget do the monitoring, allowing you to keep tabs on your heart rate without stopping, you can invest in a heart rate monitor.

Keep in mind that some forms of exercise, like swimming and biking, can make it tough to get your heart rate up to its target zone. So if steady effort isn't getting you working enough, add intensity: Stand up on the pedals if you're on a bike, or use a pull buoy if you're in the pool. Self-monitoring your effort level will become easier over time as you get used to telling what a certain heart rate feels like.

One more thing: Though effort level is important for aerobic exercise, you can also use it in strength-training if you'd like to get more of a workout. Wright advises going from exercising one body part to another to another—say, from arms to legs or abs—without stopping in between.

Next week, this blog will feature a post on strength-training, since that form of exercise will be added to the workout routine. If you have questions on any of the elements, send an E-mail to onfitness@usnews.com. I'll do my best to answer them in future installments.