Clinical trial NCT00387452: Exercise and Cardiovascular Control During Upright Tilt in Older Adults With Type 2 Diabetes
Official title: Exercise and Cardiovascular Control During Upright Tilt in Older Adults With Type 2 Diabetes
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cardiovascular
Diabetic
Keywords: Aging
Type 2 diabetes
exercise
aerobic training
strength training
glucose metabolism arterial baroreceptors
heart rate variability
cerebral autoregulation
tilt table study
transcranial Doppler
autonomic nervous system
Lead sponsor: University of British Columbia
Sponsor class: OTHER
Collaborators: name: Canadian Institutes of Health Research (CIHR)
First posted: 2006-10-13
Enrollment: 64
Sex: ALL
Minimum age (years): 65
Standard ages: OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: Older persons with diabetes have a harder time maintaining blood pressure when standing up. When blood pressure drops when standing up, fainting may occur. This study will see how regular exercise can improve the ability of the body to keep blood pressure up when standing. We want to see how this improvement varies with different types of exercise. The types of exercise that we will be studying are aerobic (running or cycling on a stationary bike) and strength training (weight lifting).

Detailed description: 1. PURPOSE: Older adults with diabetes faint frequently, due to an impairment in the cardiovascular control mechanisms (arterial baroreceptor function, autonomic nervous system function and cerebral autoregulation) that prevent syncope. The purpose of this study is to examine the ability of different intensities of aerobic exercise to reverse these impairments.
2. HYPOTHESES: a) Aerobic or strength training will improve the compensatory cardiovascular responses that prevent syncope in older adults with Type 2 diabetes. Aerobic training will:

   * increase arterial baroreflex sensitivity
   * increase heart rate variability (marker of autonomic nervous system function)
   * decrease cerebrovascular resistance
   * improve cerebral autoregulation during upright tilt. b) There will be relationship between the improvement in compensatory cardiovascular responses and aerobic or strength training.

     c) The majority of the benefits of aerobic or strength exercise on the above parameters will with which training, allowing for the design of more practicable training prescriptions than that used in a research setting.

Eligibility criteria: Inclusion Criteria:

* Type 2 diabetes for at least 5 years treated with diet alone or oral agents Nonsmoker for at least 5 years Subjects must be sedentary BMI between 24 and 35 All subjects will have a fasting glucose of \<12 mM and a hemoglobin A1c \< 8.5% All subjects must have developed hypertension CDA guidelines (systolic greater than 130 or diastolic greater than 80)

Exclusion Criteria:

* Abnormalities on complete blood count, electrolytes or creatinine, on resting ECG, treadmill exercise stress test Significant pulmonary, exercise-limiting orthopedic or neurological impairment Evidence of valvular disease, exercise-induced syncope, angina, arrhythmias or peripheral vascular disease Poor blood pressure control as defined as systolic blood pressure greater than or equal to 160 mm Hg or diastolic blood pressure greater than or equal to 90 mm Hg Total cholesterol/HDL cholesterol greater than or equal to 5.0 or LDL cholesterol greater than or equal to 4.21 mmol/L Peripheral neuropathy severe enough to cause discomfort (for safety reasons) Significant orthostatic hypotension defined as a drop in systolic blood pressure greater than 30 mmHg during one of five consecutive arterial blood pressure readings immediately after changing position from lying to standing for safety.

Overt diabetic nephropathy excluding subjects with a urine albumin to creatinine ratio of greater than 2.0 in men or 2.8 in women Diabetic retinopathy

Primary outcomes:
measure: Pulse wave velocity (central and peripheral)
measure: Drop in middle cerebral artery velocity with upright tilting
measure: Drop in blood pressure with upright tilt
measure: Arterial baroreflex sensitivity
measure: Time and frequency domain measures of heart rate variability
Secondary outcomes:
measure: Fasting blood glucose, HgbA1C
measure: VO2max
measure: Dynamometry measures of muscle strength
measure: Resting and maximal heart rate
measure: Waist to hip ratio, BMI
measure: Lean body mass/% fat
measure: Catecholamines
measure: Increase in Gosling's pulsatility index
measure: Linear transfer-function analysis of cerebral autoregulation during upright tilt
Other outcomes:
Locations:
city: Vancouver
country: Canada
facility: Vancouver General Hospital Research Pavilion
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Kenneth Madden, MD
role: PRINCIPAL_INVESTIGATOR
References: