Cadence and Intensity in Adults With Type 2 Diabetes

There will be up to two lab visits for participants, all of which will be completed in the Physical Activity and Health Lab at University of Massachusetts Amherst (consent, physical examination and entire research protocol, 2.5-3.5 hrs for all participants).

The first visit will consist of an orientation session. This orientation will begin with screening questions to determine eligibility and obtaining informed consent (45 min), followed by a physical exam and resting ECG for all participants (30 min):

Screening Questions: Participants will self-report their diagnosis of type 2 diabetes and year of diagnosis. Medication used for controlling diabetes will be determined by participants bringing their medication bottle or a photo of its label. Participants will answer additional questions (documentation attached) in an interview-style format with research staff to determine eligibility (15 min). These questions will be derived from the American Heart Association's (AHA) risk stratification found in the 2013 edition of the American College of Sports Medicine's (ACSM's) Resource for The Health Fitness Specialist. According to this screening, all participants with type 2 diabetes are considered high risk but the additional cardiac, pulmonary, and metabolic disease-related questions will be used for descriptive purposes. Given the low impact of this protocol, the volunteer's personal physician does not need to provide clearance. The PI, who is a physician, will be available to review individual circumstances prior to testing.

Informed Consent: Research staff will present an orientation slideshow to participants regarding the study purpose, study procedures, and rights as a participant (slideshow attached). Participants will then review and sign informed consent documents. (30 min)

Physical Exam: A physical exam will be conducted by study staff under the guidance of the medical director (Stuart Chipkin, MD) to assess for medical conditions that may interfere with the exercise protocol and ensure participant safety. In addition, the medical director will conduct tests for diabetic neuropathy with the neuropathy symptom and change (NSC) score, neuropathy impairment score (NIS). The NSC consists of a series of questions about neuropathy-related pain and numbness, maneuvers that relieve symptoms, and arousal from sleep. The NIS is a battery of tests that assess the ankle reflex as well as vibration, pin-prick, and temperature sensation in the great toes. (15 min)

Electrocardiogram (ECG). A resting 12-lead electrocardiogram will be performed and reviewed by the medical director prior to the exercise protocol (15 min).

Metabolic testing will then occur during the same session or a second study visit. All testing will be overseen by trained study staff with an MS or PhD in Exercise Science/Physiology or BS in Kinesiology as well as the medical director. These accommodations meet the ACSM and AHA criteria for exercise protocols. Because responses to exercise are affected by 4 hr pre-exercise food intake participants will have fasted for 4 hrs prior to testing. The metabolic testing session will be comprised of anthropometric and demographic information collection, instrument attachment, blood glucose measurement, and treadmill walking:

Anthropometrics and demographic information collection: Measures will be taken of height, seating height, body mass, body fat percentage, BMI, and waist circumference. Questions will be asked to ascertain date of birth, gender, and race/ethnicity.

Instrument attachment: Non-invasive pedometers and accelerometers will be worn by participants to measure/monitor movement during treadmill testing. The purpose of attaching these devices is to test the criterion-validity of step-counting wearable devices during treadmill walking in adults with T2DM, and compare the results to those observed with healthy adults. This is a secondary aim of the study. Participants will also be fitted with a mobile indirect calorimeter (facemask and back harness) and chest strap heart-rate monitor for measuring oxygen consumption and heart-rate.

Blood glucose measurements: The medical investigator will check fingerstick glucose values using a standard FDA-approved glucose meter before and 30 minutes after completion of treadmill testing. Following guidelines from the American Diabetes Association (Colberg SR et al; Diabetes Care 2016; 39:2065-2079. DOI: 10.2337/dc16-1728), any subject with a pre-test blood glucose < 70 mg/dl will be given 15-20 grams of carbohydrate. For glucose values between 70-150 mg/dl, study staff will administer 0.5 grams of carbohydrate per kg body mass. In addition, the medical investigator will test glucose values at any point during the protocol that a participant reports symptoms of hypoglycemia (low blood sugar) such as feeling sweaty, shaky, or weak. Subjects will be given a light snack after the testing session and informed about the potential for low blood sugars following exercise. The light snack will consist of 15-20g of simple carbohydrates or glucose.

Treadmill walking: Throughout the treadmill walking protocol, ambulatory monitoring of ECG and blood pressure will be conducted for ensuring participant safety Participants will complete a series of 5-min bouts of treadmill walking. The first bout will be performed at 0.5 mph, with concurrent bouts increasing in 0.5 mph increments, and the test will be terminated upon participant or researcher volition or completion of the first bout when the participant 1) naturally selects to run instead of walk, 2) achieved 75% of their predicted maximum heart rate, or 3) reported a Borg Rate of Perceived Exertion Scale (see attachment document ) > 13, or 4) reaches a speed of 6.0 mph. Each bout will be separated by 2-5min of standing rest on the stopped treadmill. Participants will not be seated during the resting period, as this is a submaximal protocol and fatigue preventing its continuation and requiring seated rest would be an indication to end the test.

During treadmill testing, cadence (steps/min) will be assessed by the number of directly-observed steps divided by bout duration. Redundant video recording of the participant's feet will be conducted during the entirety of treadmill testing as a back-up method to confirm step counts. Indirect calorimetry will concurrently be used to measure oxygen uptake.