Biology 105
Biology of Exercise
Spring 2003
4/7/03 - Post-class outline
Learning objectives:
How to interpret statistical information.
How does the circulation carry blood to the tissues?
Diagrams
Statistics
- why are they needed?
- how are statistical results reported?
- Null hypothesis Ho - no difference between means
- Alternative hypothesis Ha - there is a difference between means.
- Statistical tests determine whether Ho can be rejected.
- The P-value is the smallest level of significance at which Ho can be
rejected. Ho can be rejected with greater confidence as the p-value becomes
smaller.
- In many studies, statistical signficance is set at p<0.05.
- Factors that influence whether a difference is significant:
- Difference between means
- Sample sizes
- Variability
- Average (or mean) of a sample is often reported. The mean of a sample can
be considered an estimate of the true mean of the population.
- Standard deviation is a measure of the amount of variability in the sample.
- The standard error is the standard deviation divided by the square root
of the sample size. It is a measure of the reliability of the measured mean
because it takes into account both variability and sample size.
The circulatory system
During exercise, demand for flow will increase dramatically in certain tissues.
- muscles need increased flow to sustain contractions
- skin may need increased flow to dissipate heat
- heart and brain will at least need flow maintained.
- table of blood flow during exercise and rest.
Muscle blood flow can be increased by increasing cardiac output or changing
the distribution of blood flow.
- Cardiac output (CO) = stroke volume (SV) * heart rate (HR). Stroke volume
is the amount of blood pumped by each heart beat.
- Change the distribution of blood flow.
