WEEKLY HEALTH BULLETIN October 23, 2009

EXERCISE WORKS WONDERS – BUT WHICH TYPE OF EXERCISE WORKS BEST?

The research is overwhelming: people who exercise regularly live longer, have less disease, weigh less and just plain feel better.  When it comes to high blood pressure, a recent study from Norway gives us some insight into what sort of exercise works best.

It turns out that high intensity aerobic interval exercise training does a better job of lowering blood pressure and resting heart rate than moderate intensity physical activity.

The study looked at 89 patients who were split into three groups over a 12 week period:

1. Supervised aerobic interval training with a target heart rate of 90 to 95% of maximum
2. Supervised steady state  aerobic training with a target heart rate of 70% of maximum
3. Standard medical advice about the importance of exercise but with no training

Maximum heart rate is 220 minus your age.  If you’re sixty years old, your maximum heart rate would be 160 beats per minute (BPM).  90% of 160 is 144 BPM. 70% of maximum is 112 BPM.

HIGH INTENSITY INTERVAL TRAINING IS THE ANSWER

In the interval training group (90-95% of maximum heart rate), average 24 hour blood pressures (BP) went from 154/94 mm Hg to 141/87 mm Hg.  In addition, their maximal oxygen uptake (VO2 Max) improved from 36.3 mL/kg per minute to 41.7, a very impressive 15% increase.

In the moderate-intensity group (70% of maximum heart rate), average 24 hour BP went from 151/92 to 147/88 while the VO2 Max went from 34.0 to 35.8, a 5% increase.

There’s a more to this story:

Resting heart rate dropped from 73 to 69 BPM in the high intensity group but was unchanged in the others. Dilation of the brachial artery (upper arm) during exercise increased from 6.12% to 10.07% in the high intensity group but was unchanged in the others. HDL “good” cholesterol jumped from 54.5 to 57.2 mg/dL in the high intensity group; 57.6 to 58.6 in the steady state group.

Needless to say, these are impressive results, consistent with the benefits of careful high intensity interval training shown in other studies.

FOUR MINUTES HARD, THREE MINUTE EASY

The patients in the high intensity group were put on an “uphill” treadmill for 40 minutes.  After a 10 minute warm-up they were exercised for 4 minutes at an intensity that took their heart rate to 90% of maximum followed by 3 minutes at 70%.

There are no drugs that match the performance of high intensity interval training for health benefits. By the way, high intensity interval training is hard work, but worth it.

WORK WITH A TRAINER

To boost your fitness, include high intensity interval training several times a week – running/jogging, cycling, rowing or swimming.   Combine this with progressive resistance training (weights, resistance bands) for optimum overall benefit.  Best results are assured if you work with a personal trainer to set up an individualized program.  Look for ACSM, NSCA or ACE qualifications.  Good luck!

NOTE: Anyone over 40 who plans to embark on a new exercise program should be cleared by his or her doctor.  The American College of Sports Medicine recommends an exercise treadmill test as part of the process.

Alan Inglis MD
American Country Doctor