PTH And Calcium Responses to Exercise (PACE) in Older Adults
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 12
- 试验地点
- 2
- 主要终点
- Change C-Telopeptide (CTX)
研究概览
简要总结
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).
详细描述
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).
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 60 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy adults aged 60-80 y
排除标准
- •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
研究组 & 干预措施
Magnitude of Ca loss during Exercise at 26 degrees Celcius
Blood samples at 15-min intervals starting 15 min before exercise and ending 60 min after exercise.
干预措施: Magnitude of Ca loss during Exercise at 26 degrees Celcius (Procedure)
Treadmill Exercise
2 (two) 1-hour of vigorous exercise bouts under different thermal conditions, one at 16 degrees C and one at 26 degrees C.
干预措施: Treadmill Exercise (Procedure)
结局指标
主要结局
Change C-Telopeptide (CTX)
时间窗: 60 minutes of exercise and 2 hours of recovery
CTX will be measured during baseline, throughout exercise, and during recovery at regular intervals. We are looking to see how PTH changes over the course of the exercise and recovery period in both the warm and cool conditions. We anticipate that CTX will be higher during exercise and recovery in the warm condition versus the cool.
Change in Parathyroid Hormone (PTH)
时间窗: 60 minutes of exercise and 2 hours of recovery
PTH will be measured during baseline, throughout exercise, and during recovery at regular intervals. We are looking to see how PTH changes over the course of the exercise and recovery period in both the warm and cool conditions. We anticipate that PTH will be higher in the warm condition versus the cool. We expect that men and women will respond similarly.
Change in Serum Ionized Calcium (iCa)
时间窗: 60 minutes of exercise
iCa will be measured during baseline, throughout exercise, and during recovery at regular intervals. We are looking to see how PTH changes over the course of the exercise and recovery period in both the warm and cool conditions. We expect that serum iCa will be higher in the cool condition versus the warm.
Change in Total Ca
时间窗: 60 minutes of exercise
Total Ca will be measured during baseline, throughout exercise, and during recovery at regular intervals. We are looking to see how PTH changes over the course of the exercise and recovery period in both the warm and cool conditions.
次要结局
未报告次要终点