PTH And Calcium Responses to Exercise (PACE) in Older Adults

University of Colorado Denver (CU Denver)

Status: Completed

Conditions: Osteoporosis

Treatments: Procedure: Treadmill Exercise; Procedure: Magnitude of Ca loss during Exercise at 26 degrees Celcius

Study type: Interventional

Funder types: Other

Identifiers

NCT02468817

15-0250

Details and patient eligibility

About

Exercise that causes a decline in serum Calcium (Ca) as a result of dermal Ca loss stimulates bone resorption via an increase in Parathyroid Hormone (PTH).

Full description

Determine whether the magnitude of dermal Ca loss (i.e., sweating) during exercise is a determinant of the decline in iCa and increases in PTH and carboxy-terminal collagen crosslinks (CTX; marker of bone resorption). The proposed experiment will address this by manipulating the rate of dermal Ca loss (moderate vs high sweating rate) to determine whether this is the trigger for the cascade described in Figure 1. This will be achieved by having participants perform two identical exercise bouts under different thermal conditions (warm vs cool).

Enrollment: 12 patients

Sex: All

Ages: 60 to 80 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy adults aged 60-80 y

Exclusion criteria

• Use of medications in the past 6 months known to affect bone metabolism (e.g., bisphosphonates, thiazide diuretics, oral glucocorticoids)
• BMD t score < -2.5 at the total hip or lumbar spine
• Known disease or condition associated with intestinal malabsorption
• Moderate or severe renal impairment defined as an estimated glomerular filtration rate of <60 mL/min/1.73m2 based on the MDRD equation
• Chronic hepatobiliary disease, defined as liver function tests (AST, ALT) >1.5 times the upper limit of normal; if such values are obtained on initial screening and thought to be transient in nature, repeated testing will be allowed
• Thyroid dysfunction, defined as an ultrasensitive TSH <0.5 or >5.0 mU/L; volunteers with abnormal TSH values will be re-considered for participation in the study after follow-up evaluation by the PCP with initiation or adjustment of thyroid hormone replacement
• Serum calcium <8.5 or >10.3 mg/dL
• Serum 25(OH)D <20 ng/mL; volunteers with abnormal serum 25(OH)D values may be re-considered for participation in the study if serum 25(OH)D is >20 ng/mL after vitamin D supplementation
• Uncontrolled hypertension defined as resting systolic BP >150 mmHg or diastolic BP>90 mmHg; participants who do not meet these criteria at first screening will be re-evaluated, including after follow-up evaluation by the PCP with initiation or adjustment of anti-hypertensive medications
• History of type 1 or type 2 diabetes
• Cardiovascular disease; subjective or objective indicators of ischemic heart disease (e.g., angina, ST segment depression) or serious arrhythmias at rest or during the graded exercise test (GXT) without follow-up evaluation will be cause for exclusion; follow-up evaluation must include diagnostic testing (e.g., stress echocardiogram or thallium stress test) with interpretation by a cardiologist
• Diagnosis or history of asthma

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

---

12 participants in 2 patient groups

Treadmill Exercise

Active Comparator group

Description:

2 (two) 1-hour of vigorous exercise bouts under different thermal conditions, one at 16 degrees C and one at 26 degrees C.

Treatment:

Procedure: Treadmill Exercise

Magnitude of Ca loss during Exercise at 26 degrees Celcius

Experimental group

Description:

Blood samples at 15-min intervals starting 15 min before exercise and ending 60 min after exercise.

Treatment:

Procedure: Magnitude of Ca loss during Exercise at 26 degrees Celcius