Week 6 - Dallas Bedrest study Flashcards

1
Q

What did this Dallas Bedrest study seek to investigate?

A

the influence of detraining followed by training on cardiovascular function

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2
Q

What was the protocol for the study?

A

5 study participants
20 days bed-rest followed by 50 days training.

  • 2 x daily Mon-Fri. 1 x Sat
  • Continuous exercise 2.5 - 7 miles running
  • Interval training 2-5 min running at near VO2max
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3
Q

What happened to participants V02max with 20 days of bed-rest and 50 days training?

A

20days bed-rest: decreases in v02max as they began to lose the ability to take up and use oxygen.

50 days training: returned to resting levels and some participants vo2max went above their pre bed-rest values.

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4
Q

What participants saw the greatest improvement in their V02max during the training stage of the study?

A

The unfit/sedentary participants - some had a v02max greater than their pre bed-rest value.

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5
Q

What is Ficks equation?

A

Oxygen consumption = cardiac output X a-vo2 difference

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6
Q

How did this study impact cardiac rehabilitation?

A

Rather than prescribing bed rest, cardiac rehabilitation now involves exercise rehabilitation when safe to do so.

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7
Q

Following the training, how did participants HR, a-vO2 difference, CO and SV compared to after bed-rest?

A

HR lower at any given workload
CO + SV greater
a-vO2 difference increases sooner with BR

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8
Q

What happened to SV after training? How does this compare to before the study?

A

SV improved with training and there is a linear increase in stroke volume with oxygen consumption.
This differs to before the study where SV starts to plateau at around 40% of their V02max. Therefore, you get a much greater cardiac output relative to control and bed-rest period.

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9
Q

What happened to a-vo2 difference after training?

A

a-vo2 difference capacity was greater with training compared to control and bed-rest

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10
Q

Why is there a higher oxygen uptake when sedentary (control) compared to after bed-rest? How can we explain the further increases in oxygen uptake after training?

A

Sedentary had higher oxygen uptake due to an increase maximal cardiac output relative to after-bed rest, caused by changes in SV (huge decrease after bed-rest).

Further increases with training is due to increase in cardiac output, caused by increased SV and changes in a-vo2 difference capacity.

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