I recently added two more cardio days to the 5 I already do, but they are light days. On these 2 days I walk 20 to 30 minutes at 3 m.p.h. (slower than the 4 m.p.h. on my 5 heavy days). My heart rate barely goes over 100; I usually keep it between 127 and 137 (70 - 75 percent of my max). My question is: Am I just wasting my time doing these light days? Should I walk at this pace longer or does it matter? Thanks for your help.

--iVillager linda

We think it is excellent that you're eager to add light days to your exercise routine. It shows you're committed to your program and willing to push yourself in order to achieve your goals. However -- ironically -- the first thing we suggest is doing absolutely zippo at least one day every week to rest your tired muscles. When you train to improve muscle tone, aerobic power and other aspects of fitness, your body gets tired and needs a break. "Zippo" days are required to rebuild any broken down muscle tissue. You may need more than one of these complete rest days some weeks so listen to your body and keep an open mind.

That said, adding one light day to your current routine is a great way to loosen up your body and satisfy your desire to "keep moving." Besides the leisure walking you're already doing, we suggest trying something relaxing and non-aerobic like yoga, Pilates, traditional stretching or t'ai chi. There are a lot of benefits to doing this type of exercise a few days a week. You'll improve your flexibility, posture and overall body awareness. You may even improve your spiritual health as these activities make a connection between body, mind and soul.

Another way you can up your fitness level and burn extra calories: Try some interval training a couple of days a week. For instance, if you're walking on a treadmill, increase the speed or incline to raise your heart rate to about 85 percent of your maximum for 1 minute. Then decrease the speed or grade to lower your heart rate to about 65 percent of your maximum for 1-2 minutes. The goal here is to challenge yourself at a high intensity, then recover enough to kick up the intensity again. This type of workout burns a lot of fat and calories because the harder you push yourself, the more fat and calories you burn.

Start your interval workout with a 5-minute warm up, then jump right into a hard minute of exercise. Next, lower the intensity and recover for 2 minutes. Rotate this work/rest system for a total of 30 minutes and then cool down for 5 minutes. This will give you a great 40-minute workout. Just be careful not to burn yourself out in the beginning. You may not be able to do the full 10 intervals when you first try this type of workout. You can gradually increase the number of intervals in as your fitness level improves. Beginners should also give themselves the full 2 minutes of recovery between hard intervals.

If you're not comfortable taking your heart rate while you're moving, you can use a rating scale of 1-10 to determine your workout intensity, 1 representing a very light intensity and 10 representing a very, very high intensity. For instance, during the high work period of your interval you should be around 8-9; during your rest period around 6-7.

Finally, we've noticed you did not mention weight training as part of your current exercise routine. We recommend that you weight train at least twice a week to help strengthen your muscles, prevent osteoporosis and -- believe it or not -- help you burn fat and calories at a greater rate. The muscle you build by weight training helps speed up your metabolism.

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