Given that sedentary behavior is associated with T2DM, the purpose of this study is to
evaluate whether subjects with T2DM have a significant disincentive to performing exercise
(due to greater perceived effort) . This study will prospectively compare the perceived
exercise effort between T2DM and non-diabetic women while adjusting for potential
confounders including baseline physical activity. This study will also assess whether
perception of effort is associated with physiologic parameters related to exercise effort.
Finally, we have 3 hypothesis-generating exploratory aims designed to screen for additional
psychological and physiologic parameters that may increase perceived effort in those with
Hypothesis 1: At the same absolute workload (e.g., 30 watts) and the same relative
workloads, it is a greater effort for women with T2DM to exercise than for non-diabetic
Specific Aim 1: To determine differences in subjective perceived effort of bicycle exercise
at low-to-moderate workloads in sedentary women with Type 2 Diabetes Mellitus (T2DM) vs.
non-diabetic sedentary women.
Hypothesis 2: There will be a significant association between RPE and the physiologic
measures related to work intensity (e.g., relative work intensity and tau2).
Specific Aim 2: In the same populations as SA1, to determine the strength of association
during bicycle exercise between subjective perceived effort and physiologic measures related
to work intensity.
Exploratory Aim 1: In the T2DM group described in SA1, to determine the strength of
association during bicycle exercise between subjective effort and additional physiologic
Exploratory Aim 2: In the T2DM group described in SA1, to determine the strength of
association during bicycle exercise between subjective effort and psychologic measures
related to perception of effort.
||Observational Model: Cohort, Time Perspective: Prospective
|Ages Eligible for Study:||50 Years|
|Genders Eligible for Study:||Female|
|Accepts Healthy Volunteers:||Accepts Healthy Volunteers|
- Sedentary women not participating in a regular exercise program (> one bout of
exercise per week)
- If subject has diabetes, must be uncomplicated T2DM and < 25 years since T2DM
- Ages of 50-70 years
- BMI of 25-35
- Subjects can only be taking the following oral hypoglycemic drugs: metformin,
sulfonylureas or sitagliptin. Use of insulin or other oral hypoglycemic medications
is not allowed.
- Persons with T2DM will be accepted for study only if they have total glycosylated
hemoglobin levels (HbA1C) <8% (adequate control) on therapy.
- Control subjects must have HbA1C < 5.5% and a fasting blood glucose of <100 mg/dl
suggesting no significant insulin resistance.
- All women must be post-menopausal, documented by menstrual history and follicle
stimulating hormone (FSH) level.
- Current smokers will be excluded since smoking can impair CV exercise performance but
people who have quit smoking for at least 1 year will be accepted for study.
- Absence of comorbid conditions will be confirmed by history, physical examination and
- In general, people will be excluded with any condition which could limit exercise
- Persons with clinically evident distal symmetrical neuropathy, determined by
evaluation of symptoms (numbness, paresthesia) and signs (elicited by vibration,
pinprick, light touch, ankle jerks), will be excluded from further study as
neuropathy may limit exercise performance.
- Persons with autonomic dysfunction (>20 mm fall in upright BP without a change in
heart rate) will be excluded as well, due to associated limitations of exercise
- Persons will be excluded if they have evidence of heart disease by history (Prior
heart attack or bypass surgery, heart failure, or significant valvular disease) or
abnormal resting electrocardiogram (EKG) consistent with prior infarct or latent
ischemia (unless cardiovascular stress imaging or catheterization shows they do not
have coronary artery disease). We will also exclude subjects with left or right
bundle branch block on resting EKG (precludes recognition of ischemic EKG changes
with exercise) or abnormal exercise EKG (> 1 mm ST segment depression 80 msec out in
the ST segment for 3 consecutive beats).
- Persons with angina or any other exercise-limiting cardiovascular, pulmonary or
musculoskeletal symptoms will be excluded as well.
- Presence of systolic blood pressure >150 at rest or >250 with exercise or diastolic
pressure >95 at rest or >105 with exercise are also grounds for exclusion.
- Subjects with proteinuria (urine protein >200 mg/dl) or a creatinine > 2 mg/dl,
suggestive of renal disease will be excluded.
- Subjects with total cholesterol >220 mg/dl, low density lipoprotein > 130 mg/dl, or
triglycerides > 250 mg/dl will be excluded given the potential insulin resistance and
endothelial dysfunction associated with these cholesterol parameters.
- Subjects taking the following medications will be excluded: insulin, oral
hypoglycemic agents other than those stated in inclusion criteria,
estrogen-containing hormone replacement therapy including the "estring".
- Control subjects who have an immediate family member with type 2 diabetes will be