Kenneth Gardner - FITNESS CLUB

Dear Dr Gardner,

I have had two knee-replacement operations and my doctor suggests that I walk 45 minutes per day. Is that enough exercise for my heart?

-Kathleen

Response to reader

Dear Reader,

Walking for 45 minutes can be an easy walk in the park for some of us but a challenge for those who are in poor physical shape. There are many variables, such as the pace or the rate at which you walk, how far you walk in 45 minutes, and if you are walking for 45 minutes non-stop, and so on. Thus, you can walk for 45 minutes and benefit considerably or minimally from the effort.

There are many prescriptions that can be recommended for walking. Each one will be guided by factors related to the individual's profile. The benefits from walking will be influenced by the intensity, duration, distance and frequency. These factors influence each other and the final result of your walking routine. It is difficult to say how useful your 45-minute walk will be for your cardiovascular system without more information on the variables in your situation.

Brisk walks

Brisk walking at a rate of four miles an hour or faster improves one's cardiovascular and cardiorespiratory health. Walking is one of the best activities to start a conditioning programme. Inactive people should begin by walking about a mile, four or five times each week. Each week, you can increase the length of time you walk by about five minutes. If you have been walking for three to four weeks, you should be able to walk a distance of a mile in seven and a half minutes. The further you can walk at a faster pace, swinging your arms, the more cardiovascular benefits you will achieve.

You can make your walking routine more efficient by walking with light weights in your hand or carrying a backpack with weights as light as five pounds. However, if you have any cardiovascular problems, the additional weights will require close scrutiny.

Walking in water at chest height is an excellent way to improve your cardiovascular fitness, especially if you have knee and back problems. The water reduces the pressure of your weight on your knees and provides enough resistance to make the intensity high enough to give your heart a good work out. You can walk for very long periods without achieving any cardiovascular improvements when the intensity is below the threshold to increase your heart rate to your target zone. Yet, you can walk for a shorter period of time at a faster rate and achieve improved benefits.

When you do your daily walk, you should start at a comfortable level so that you can maintain the pace as well as a conversation with your walking partner. If this is a challenge, you are walking too fast. As you improve, you can increase the duration of each session with a 10 per cent increment weekly. The increase should be just enough to keep your heart rate in your target zone.

Dr Kenneth Gardner is an exercise physiologist at Holiday Hills Research Center; email: yourhealth@gleanerjm.com.