NEWSLETTER Winter 08: Interval Cardio
Interval Cardio: The Fastest Way To Burn Fat and Strengthen Your Heart
By Terry Christensen, BSc.PT, C.S.C.S.
Registered Physiotherapist (Athlete's Care, Yonge & Eglinton)
You do not need to do endurance exercises to burn fat or strengthen your heart. In fact, studies have now shown us that short sessions of high intensity interval cardio develop aerobic fitness, preserve muscle mass and can burn fat more effectively than conventional cardio work-outs. Interval training is simply short, intense bursts of near maximal effort followed by a rest period. Cardiologists are recommending interval training because it trains the heart to efficiently speed up and slow down in response to exercise.
A study published last year in the New England Journal of Medicine concluded, individuals with the greatest ranges between their heart rates during intense exercise and rest were four times less likely to have a heart attack.
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Interval training helps your heart to respond quickly to the demands of sport and life. Sprinting or cycling at near maximal speed forces your muscles to work at a higher intensity. This practically mirrors weight training, giving you the same hormonal release (growth-hormone and testosterone) that will protect and support lean muscle mass.
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Intervals also allow your body to produce another hormone, glucagon, which causes you to burn calories directly from your fat stores.
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Finally, like weight training, intervals will raise your metabolism for up to 24-48 hours after your workout, letting your body fight fat long after you have left the gym!
A sample work-out:
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Warm-up on a treadmill or bike for five minutes
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Sprint or cycle for 30 seconds at 70%-90% of your all-out effort (just about your top speed). This of course will vary among individuals.
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Slow down to 40%-50% of your all-out effort (a brisk but comfortable pace) for one minute. That is one interval.
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Repeat for a total of six to eight intervals.
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Work at an easy pace for a five minute cool-down.
Remember these are general guidelines only. You should always consult a professional when initiating or changing your exercise program.
