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Monday, August 30, 2010

Heart Attack Deaths in the U.S. Have Dropped Sharply

In the Harvard Health Letter, vol 35, no. 10, August 2010, and article appeared entitled, "Is the heart attack going out of style?". It stated that, based on Medicare data, the U.S. heart-attack hospitalization rate declined by 23% from 2002 to 2007. Also, a study based on 3 million members of a northern California health plan showed a 24% drop in heart attack hospitalizations between 1999 and 2008. While an increasing number of people are diagnosed with heart disease, fewer are dying from it - heart attack deaths have been declining in the U.S. for the past 40 years.

The article conjectures that, "Maybe decades of efforts to eat right and exercise more, stop smoking, lower LDL cholesterol levels, and control blood pressure are working." This appears only partially true. Yes, fewer Americans smoke, and Lipitor, a medication for reducing LDL and total cholesterol, is the most prescribed drug in the U.S. Many people are also taking blood pressure medication. Yet, there is little evidence that people are "eating right" as fast-food consumption and obesity continue to increase. Also, various national campaigns, such as the American College of Sports Medicine's Healthy People 2000, have failed dismally to get people to exercise more. Thus, it appears that the reduction in heart attacks is less due to anything that requires will power than to modern medicine. Another possible factor is reduced stress, as the economy was doing well over the study period. It remains to be seen what the recession and high unemployment rate will do to the heart attack rate. Hopefully, and emphasis on family and personal fulfillment and relationships will help keep stress to a minimum, even in the face of economic difficulties.

The reduction in heart attacks is encouraging, yet it would be even better if people became healthier through lifestyle changes such as exercise and good nutrition.

Wednesday, August 4, 2010

Mixed-Intensity Interval Training vs. Steady-Speed Running

Evidence continues to pile up concerning the advantages of interval training. A study by James Clark in the Journal of Strength and Conditioning Research (vol. 24, no. 7, pp. 1773-1781, 2010) compared interval training comprised of runs of varying lengths and intensities to steady-speed running as to which produced greater improvements in maximal oxygen uptake (VO2max), the gold standard of aerobic fitness.

Study Procedure
The subjects were 32 female league and college competitive soccer players who were divided into 2 groups that trained as follows for 8 weeks:

1) Mixed-Intensity Interval Training (MIIT): The workout consisted of repetitions of the following 6-minute exercise cycle:
  • 30 sec of jogging
  • 30 sec running at 90-100% of max effort
  • 60 sec of jogging
  • 60 sec running at 80-90% of max effort
  • 90 sec of jogging
  • 90 sec running at 70-80% of max effort
      The subjects did 2 cycles (12 min) the first week and increased to 6 cycles (36 min) by the eighth week.

2) Steady-Speed Training (SST): They ran steadily at a "moderate to hard" pace (heart rate corresponding to 60-80% of that at maximal oxygen uptake). Run time was 40 minutes the first week and increased to 60 minutes by the eighth week.

The mixed-intensity interval training group improved in maximal oxygen uptake by over 25% while the steady-speed training group improved less than 17%, a statistically significant difference.

Bottom Line
The mixed-intensity interval training improved aerobic fitness more than did steady-speed running, and required less time per workout. In addition, while it was not tested, it is likely that the sprinting segments of the interval training produced more improvement in sprinting ability, which is essential for soccer and other sports requiring bursts of speed. Thus, it appears that mixed-intensity interval training is advantageous for athletes in various team sports. Steady-speed running is still important for distance runners, who generally work out at various intensities during a training week.

NOTE: This description of experimental results is for informational purposes only and does not constitute a recommendation. Anyone engaging in an exercise program should obtain proper medical authorization before doing so.