Human Limits

Exploring performance and health with Michael J. Joyner, M.D.

Photo of Michael J. Joyner, M.D.

3 Weeks = 30 Years!

Last week I had the opportunity to attend the “Integrative Biology of Exercise” conference sponsored by the American Physiological Society.   During an excellent talk on how exercise training can modify the changes in heart function with age, Dr. Ben Levine showed classic data from a study done in the middle 1960s known as the Dallas Bed Rest Study.

In this study 5 healthy young men did nothing but bed rest for three weeks while detailed measurements of their cardiovascular function and exercise capacity were measured.    Not surprisingly, cardiac function declined and exercise capacity fell dramatically with bed rest.   The figure below shows what happened to VO2 max which is considered the gold standard measurement of exercise capacity after bed rest.

 

 

What is even more interesting about this figure is that when the same subjects were studied 30 years after the original bed rest study, their VO2 max fell more with just three weeks of bed rest than with 30 years of aging.   Below is a video link of Dr. Levine talking about his work on related topics.

 

 If video does not load, click here.

 

Another interesting video on the topic of inactivity comes from Dr. Bente Pedersen of the University of Copenhagen.    Her team has conducted an incredible study showing that just two weeks of minimal physical activity can put previously health young men on the path to what might be described as pre-diabetes.    In the video below she discusses these findings and also concepts related to the fit vs. fat topic covered a few posts ago.

 

If video does not load, click here.

 

These are terrific talks by scientific leaders who are my friends and colleagues.  One of the great things about the electronic environment is that presentations by such outstanding investigators are available to us all.

 

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One Response to “3 Weeks = 30 Years!”

  1. October 18th, 2012 at 7:00 am

    John says:

    Hi Mike
    this is really a fascinating area of study. I have actually used the Dallas Bed Rest study in my in-patient clinical work to get long term hospital inpatients (e.g., stem cell transplant, etc) motivated to engage in daily physical activity even if it is just walking the hallways two or three times a day. Patients and most health care providors have no idea how quickly our physical fitness and muscular tone can atrophy under minimally active conditions. In my opinion, all inpatient hospital floor should have an exercise room for patient use with treadmills/recumbent bikes etc.

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