1. S TAT 1000: S EMINAR 11 Mitchell Thompson

2.  Purpose: To test the hypothesis that greater intolerance in women would be associated with lesser responsiveness of specific mechanisms that underlie blood regulation.  Terms:  Orthostatic Compromise – “head rush” caused by sudden drop in blood pressure when a person stands up right  Isoprotenol- a drug that has various effects on the cardiovascular system such as HR

3.  Variable Situation ??  Two-sample vs. Paired Study  P AIRED S TUDY  Sample vs. Population  M EN (n=10) W OMAN (n=7)

4.  All subjects were non-smokers and normotensive  Selection of screening based on results of screening evaluation  selection bias?  Female subjects were: tested during the follicular phase of their menstrual cycle, not pregnant, not using oral contraceptives  Individuals with history of hyperthyroidism or taking R x drugs were excluded  Why?  To decrease the amount of confounding variables Table 1. Subject descriptive data VariableMen (n = 10)Women (n = 7)FP Age, yr38 ± 2 36 ± 2 0.6350.438 Height, cm175 ± 2 164 ± 3 11.7290.004 Weight, kg78.9 ± 2.5 64.8 ± 3.8 10.7460.005 Estimated body fat, % 14.7 ± 1.0 24.6 ± 2.0 15.8850.001 Rest SBP, mmHg122 ± 2 113 ± 3 5.9930.027 Rest DBP, mmHg74 ± 2 70 ± 1 1.9070.188 Rest heart rate, beats/min52 ± 2 65 ± 4 9.1620.009 Max heart rate, beats/min 184 ± 3 190 ± 5 1.3980.257 V O 2 max, ml · kg 1 · min 1 47.4 ± 1.9 39.5 ± 1.6 7.3250.018 V O 2 max, ml · kg LBM 1 · min 1 55.5 ± 1.9 53.6 ± 3.3 0.2790.606 Values are means ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; O 2 max, maximal oxygen uptake; LBM, lean body mass.

5. Copyright ©1998 American Physiological Society Convertino, V. A. Am J Physiol Regul Integr Comp Physiol 275: R1909-R1920 1998 Fig. 6.  Explanatory/Response?  Isoprotenol (explanatory)  HR (response)  + or – Relationship?  positive (+)  linear equation for females is y = 1,880x - 61.8 males is y = 1,303x - 52.6

6. Copyright ©1998 American Physiological Society Convertino, V. A. Am J Physiol Regul Integr Comp Physiol 275: R1909-R1920 1998 Fig. 6.  Explanatory/Response?  Isoprotenol (explanatory)  LVR (response)  + or – Relationship?  negative (-)  linear equation for females is y = -865x - 48.5 males is y = -690x - 51.7

8. SCATTER PLOT (LESS ERROR) BOX PLOT (LESS SPREAD)

9. SCATTER PLOT (MORE ERROR) BOX PLOT (MORE SPREAD)

10.  Strong or Weak?  Iso vs. HR ▪ Females: r= + √0.995 = 0.997 ▪ Males: r= + √0.993 = 0.996  Iso v. LVR ▪ Females: r= -√0.957 = -0.978 ▪ Males: r = -√0.876 = -0.936  Correlation based on average tends to overstate strength because scatter due to individuals has been reduced.

11.  Question: Does bias arise in the sample or design?  Answer: Tricky  The sample of men and women are taken from the Air Force Base  Sample is not representative of general population

12.  LBNP tolerance was significantly lower in females than males who matched for age and aerobic fitness in the Air Force.  G-suit designed