Do diabetic women feel it is harder to exercise than nondiabetic women GIM TMR 6122007

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Do diabetic women feel it is harder to exercise
than non-diabetic women?GIM TMR6/12/2007

• Amy Huebschmann, MD
• Tim Bauer, MD
• L.Miriam Dickinson, PhD
• Caroline Emsermann, MS
• Jane Reusch, MD
• Erin Kahler, MD
• Judy Regensteiner, PhD

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Background

• Worse exercise capacity in Type 2 Diabetes (T2DM)
  than non-diabetic controls
• Exercise Cornerstone of T2DM therapy
• Improves insulin sensitivity
• Improves all-cause mortality
• Poor exercise compliance despite above benefits

Regensteiner JG, Rev Endocr Metab Disord, 2004
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Objectives

• Global Goal of our Body of Work
• To understand the abnormalities in both the
  cardiovascular system and local blood flow to
  exercising muscle which impair exercise capacity
  in persons with Type 2 Diabetes Mellitus (T2DM)

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Objectives

• Goal of my research well address today
• To recognize the differences in perceived effort
  of exercise in subjects with T2DM vs. obese and
  normal weight controls

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Maximal Exercise Capacity impaired in T2DM
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Dysmetabolic Environment in T2DM
Huebschmann, et al. Diabetes Care, 2006
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Maximal Exercise Capacity impaired in T2DM
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Endothelial Dysfunction
Impaired vasomotor tone
Prothrombotic state
Pro-inflammatory state
Proliferation in arterial wall
Decreased blood flow due to decreased vascular
relaxation
Atherosclerotic Lesion formation/progression Plaq
ue Activation/Rupture
CV Disease Events
Adapted from Widlansky ME, et al. JACC 2003.
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Maximal Exercise Capacity impaired in T2DM
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Peripheral Muscle Dysfunction

• Endothelial dysfunction-related
• Impaired vasodilation - decreased blood flow to
  working muscles
• Intrinsically muscle-related
• Reduced muscle oxidative enzyme activity
• Greater muscle Type IIb/Type I fiber ratio may
  decrease oxygen extraction

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Maximal Exercise Capacity impaired in T2DM
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Cardiac Dysfunction

• Diabetic Cardiomyopathy subclinically
  impaired LV function during exercise
• Endothelial Dysfunction possible role
• impaired dilation of coronary arteries

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Cardiac Dysfunction Worse Exercise capacity and
Rising Pulm Wedge Pressure with Exercise
Pmaximal oxygen consumption
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Review Background

• Worse exercise capacity in Type 2 Diabetes (T2DM)
  than non-diabetic controls
• Exercise Cornerstone of T2DM therapy
• Improves insulin sensitivity
• Improves all-cause mortality
• Poor exercise compliance despite above benefits

Regensteiner JG, Rev Endocr Metab Disord, 2004
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• Research Question
• Why is exercise under-utilized by those with
  T2DM?
• Hypothesis
• People with T2DM do not exercise regularly in
  part because at the same workload it is a greater
  effort for them than it is for the non-diabetic
  population.

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Research Objectives

• To determine differences in perceived exertion of
  low resistance bicycling between sedentary women
  with T2DM and two control groups
• 1) sedentary non-diabetic overweight women
• 2) sedentary non-diabetic normal weight women

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Research Objectives - continued

• To determine differences in perceived exertion of
  low resistance bicycling between the same 3
  groups after 12 weeks of exercise training

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Methods Study Design

• Non-blinded clinical trial with exercise
  intervention
• Three study arms
• Sedentary premenopausal women with T2DM
• Sedentary non-diabetic premenopausal overweight
  women
• Sedentary non-diabetic premenopausal normal
  weight women

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Methods Study Sample
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Exercise Intervention

• 12 weeks of exercise cross-training on treadmill,
  bicycle ergometer, and rowing machines
• Thrice-weekly monitored 60-minute exercise
  sessions at 70 to 85 of maximal exercise capacity

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Methods Study Sample

• Inclusion Criteria
• Premenopausal women, aged 30-50
• Sedentary based on results of LOPAR survey
• T2DM disease confirmed by chart review for T2DM
  arm

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Methods Study Sample

• Exclusion Criteria
• Cardiovascular disease (by hx or ETT)
• Pulmonary symptoms limiting exercise
• Chronic Kidney Disease (Uprot 200 mg/dl or Cr
  2.0 mg/dl)
• Peripheral Neuropathy
• Abnormal echocardiogram

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Methods- Study Protocol
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Outcome Measure

• Rate of Perceived Exertion (RPE)
• Validated in multiple studies
• Gold Standard measurement of exercise perception
• Correlates well with physiologic variables
• oxygen consumption (r 0.63)
• heart rate (r 0.62)
• blood lactate (r 0.57)

Chen, MJ et al. Journal of Sports Sciences, 2002
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Methods Analytic Plan

• Mixed Effects Repeated Measures Model used to
  determine
• Differences in mean RPE between 3 groups at entry
• Differences in mean RPE between 3 groups at entry
  after adjustment for baseline physical activity
  and work intensity of exercise
• Differences in pre-post differences of mean RPE
  between 3 groups after exercise intervention

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Results
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Subject Characteristics
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P RPE for control group vs. T2DM
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RPE, Rate of Perceived Exertion LOPAR, Low Level
Physical Activity Recall Questionnaire Work
Intensity, VO2ss/VO2max pT2DM
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Strengths

• Homogeneous group of women in intervention and
  control groups (pre-menopausal, young)
• Uncomplicated nature of recent onset T2DM
  confirmed by ETT and ECHO
• RPE scale well-validated in many disease states

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Limitations

• Generalizable to Premenopausal Women
• RPE does not clarify site of greatest effort
  (e.g., breathing vs. legs)
• Sample size limits Power and ability to adjust
  for multiple covariates

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Conclusions

• Greater perceived effort with low intensity
  activities may inhibit motivation to be active in
  women with T2DM
• Future research directions
• Are muscle fatigue or respiratory symptoms or
  both accounting for the greater effort?
• What physiologic mechanisms account for the
  greater effort?
• Are disparate perceptions of effort are also
  present in men and post-menopausal women?

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References

• Regensteiner, JG. T2DM and Cardiovascular
  Exercise Performance. Rev Endocr Metab Disord
  2004 5269-267.
• Widlansky, ME, et al. Clin Implications of
  Endothelial Dysfunction. JACC 2003 421149-60.
• Huebschmann, AG, et al. Diabetes and Advanced
  Glycoxidation End Products, Diabetes Care 2006
  
• Chen, MJ et al. RPE meta-analysis. J Sports
  Scie, 2002 20873-899.

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Questions?