Are you exercising right? – includes related information
To keep fit and strengthen the heart all healthy adults should try to do rhythmic exercise, using large muscle groups such as the arms, legs and back, for 20-30 minutes at least three times a week. The aim is to provide “aerobic exercise” for the heart and body by brisk walking, dancing, jogging, rollerblading, rowing or bicycling – whatever suits you and gets the cardiovascular system working for long enough and hard enough.
Aerobic exercise is the key
Aerobic means “oxygen using.” During an aerobic workout, the heart pumps blood saturated with oxygen around the body, burning fat at the same time. More fat is burned when the muscles move steadily at an aerobic pace for 10-15 minutes or longer. But it takes a while for the aerobic process to get into full swing; it doesn’t happen just with a short sprint to the bus or brief burst of snow-clearing. Working both arms and legs gives the best aerobic workout. Using primarily the arms – as in swimming – is less effective than a fast walk or jogging. Steady aerobic exercise increases cardiac strength and improves the heart’s ability to pump blood with each beat, delivering oxygen throughout the body with less effort. The fitter your heart, the greater the ability to work without tiring. Moderate aerobic exercise energizes the body and reduces fatigue.
Start with a gentle exercise routine,” advises one University of Toronto physiologist, “and work up to a more vigorous, fully aerobic program. Increase activity slowly and comfortably.” For starters, people can do at least 5-10 minutes of exercise a day – a brisk walk, cycling, dancing, housecleaning, tennis or swimming. Five minutes of daily activity is the minimum required if you want to increase endurance and strengthen the muscles, ligaments and tendons. Step up the pace to a comfortable level and try to keep going for 20 to 30 minutes. Work to a goal of 30 minutes after the initial six weeks or so of a gentler routine.
The maximum exercise routine is a vigorous workout that will improve endurance and increase oxygen intake. Maximum routine activities include jogging, squash, running, hockey, singles tennis or badminton, vigorous curling, skiing, judo and hiking. Check whether the exercise is in the right range by a combination of heart rate and breathing. Your heart rate should be within the range for your own age, and you should be able to talk and hear your breathing while exercising.
Exercise within the right target heart rate zone
How do you know whether the exercise is aerobic and provides cardiovascular benefit? The heart rate per minute for ideal aerobic exercise should be within a specific range, with an upper and lower limit (see table). Traditionally, the optimal exercise level is calculated using the person’s age to determine whether it’s vigorous enough to strengthen the heart. Getting “heart fit” means working the heart within the target zone for 20-30 minutes several times a week, enabling the heart to pump more blood without causing fatigue. An unfit 40- or 50-year-old who generally pants and tires after a 15-minute walk will gradually be able to keep up an easy jog or fast walk for half an hour without tiring.
[TABULAR DATA OMITTED]Calculate the maximum safe aerobic exercise zone by subtracting your age from 220; your personal target heart rate should fall within 60-85 per cent of that number. The cutoff (stop or “slow down”) point is at 85 per cent of that figure. Exercising above that level does not benefit the heart. In fact, exercising too hard may make the exercise “anaerobic” (without oxygen), leading to exhaustion, and you will no longer be burning fat.
Measure the heart rate by pressing two fingers gently on the carotid artery, which runs up the neck alongside the jawbone, and count the beats per 10 seconds, then multiply by six. The exercising heartrate zone of a 20-30-year-old man or woman should range from 144 to 174 beats per minute (24-29 in 10 seconds); a 50-60-year-old man or woman will have an exercising heart rate between 108 and 138 beats per minute (18-23 in 10 seconds).
Do the talk and breathing test
As an informal, more convenient alternative to measuring the pulse, try the voice-and-breathing test developed by University of Toronto researchers. You should exercise at a level at which the breathing is audible and you’re just capable of carrying on a conversation. You should always be able to talk while exercising – if you can’t, you’re working too strenuously.
The voice test arose from a story about Scottish mountain climbers who have to work hard in an oxygen-poor environment. Climbers need to know when they are near their maximum exercise capacity, and as they can’t easily check their pulse for fear of toppling off cliffs, they have a rule of thumb: never climb faster than you can talk. This rule has been translated by University of Toronto researchers into a handy test to judge exercise efforts.
The breathing-and-voice test is a guide to the target heart zone whether people are fit or unfit, male or female, taking certain medications or just feeling lethargic. People should exercise within the voice-or-talk zone at any age. Increase activity to the point where breathing is heavy and audible, without wheezing or panting. You’re in the aerobic zone when breathing heavily (audibly) but still able to speak.
As people exercise more vigorously, at a certain level they cross the upper threshold for aerobic exercise – depending on age and/or fitness levels – and at that point exercise becomes partly anaerobic with an increase in lactic acid (a waste substance that causes fatigue). At this point, you have exceeded the maximum aerobic-exercise tolerance. As the body accumulates lactic acid, it forces you to slow down or stop. Lactic acid also stimulates very heavy breathing. Since panting and talking are hard to do at the same time, at the upper end of your aerobic capacity you should be barely able to carry on a conversation; when you can no longer talk, you’ve exceeded your capacity, and it’s time to slow down.
Not all exercise is aerobic!
If exercise is too slow or too energetic, aerobic strength is not increased. Slow walking, for example – although it burns calories – does not increase the heart rate enough to upgrade cardiac fitness. Weightlifting strengthens the arms and back but does not increase the heart rate for long enough to provide cardiac benefit. On the other hand, a brisk walk or swim lasting about 20 minutes) increases oxygen availability throughout the body rather than just to the specific muscle groups used in weightlifting. if it’s fast enough it will strengthen the heart.
COPYRIGHT 1995 Strategic Inc. Communications Ltd.
COPYRIGHT 2004 Gale Group
