SPLMNTL CALCIUM TO OFFSET BONE MINERAL DENSITY LOSS IN COMPETITIVE MALE CYCLISTS

SPLMNTL 钙可抵消男性自行车运动员的骨矿物质密度损失

• 批准号: 7604451
• 负责人: DAN BARRY
• 金额: $ 2.73万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7604451
• 关键词: Address; Attenuated; Body Weight; Bone Density; Calcium; Computer Retrieval of Information on Scientific Projects Database; Condition; Dermal; Exercise; Funding; Goals; Grant; Hormones; Hour; Human; Inflammation; Inflammatory; Institution; Intake; Length; Manufactured basketball; Measures; Methods; Outcome Measure; Participant; Pilot Projects; Placebos; Production; Race; Randomized; Recommended Daily Allowances; Research; Research Personnel; Resources; Risk; Role; Seasons; Simulate; Source; Sports; Strenuous Exercise; Stress; Sweat; Sweating; Training; United States National Institutes of Health; Urine; Visit; Water consumption; Week; aged; bone health; bone loss; bone metabolism; college; day; drinking; male; men; prospective; sex

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Rationale Although it is generally true that exercise is beneficial for bone health,1 under certain conditions exercise can be associated with loss of bone mineral density (BMD). In this pilot study, we will evaluate the impact of calcium (Ca) loss through sweating on bone density. One study of calcium loss and bone density in athletes4 found that male college basketball players had significant decreases in total BMD over the course of a season. When the same athletes were given supplemental Ca in the form of a Ca-fortified sports drink the following competitive season, there was an increase in BMD rather than a loss. To further explore the potential role of calcium loss through sweat, we have chosen to conduct the study in competitive road cyclists. Their high training volume (10-15 h/wk or more) is expected to generate a large sweat Ca loss. Also, the training/competitive season for road cycling is relatively long (Jan to Sept), which is suitable for determining the effects on bone metabolism. Another reason we chose to study road cyclists is because they appear to be at increased risk for low BMD.6-12 We will examine the loss of calcium through sweat in this pilot study as one potential mechanism of loss of BMD. However, strenuous exercise has also been found to disrupt sex and stress hormone levels in humans.13-16 Strenuous exercise may also result in systemic inflammation.17-19 These alterations may also effect bone metabolism. Aims and Hypotheses: The primary goal of this Pilot Study is to evaluate in a prospective, controlled fashion a potential mechanism by which vigorous, prolonged exercise (both in terms of length of an exercise bout and duration of the training/competitive season) may promote bone loss. Our hypotheses are as follows: H1: Dermal Ca loss as a result of prolonged, vigorous exercise training is a significant determinant of bone loss in competitive road cyclists over a season of training and competition. H2: Increasing Ca intake to higher than currently recommended levels (2000 mg/d) will attenuate the loss of bone in competitive road cyclists over a season of training and competition. Methods: To address these hypotheses, we will study 20 competitive cyclists over a season of training and competition. Participants will be men aged 18-35 yr who have been racing for 2 or more seasons and train 10 or more hours/week. They will have baseline calcium intakes at or below the recommended daily allowance of 1000mg/day. They will be randomized to take placebo or supplemental calcium to 1800-2000mg/day or maintain their usual intake of 1000-1200mg/day. Participants will perform a 2 hour simulated training ride on a stationary trainer at baseline, mid-season, and after the season ends. BMD will be measured at these visits, and estimates of their sweat calcium loss will be determined by measuring sweat calcium concentrations and determining sweat loss (estimated from change in body weight corrected for water consumption and urine production). Analysis: Our primary outcome measure is BMD in the placebo non-supplemented vs. the calcium supplemented group. We will attempt to control for confounders such as changes in sex and stress hormones, inflammatory makers, and change in body weight through the season.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 理由 尽管运动通常对骨骼健康有益，但在某些条件下，运动可能与骨矿物质密度（BMD）的损失有关。在这项初步研究中，我们将通过出汗对骨密度的钙（CA）损失的影响评估。 一项关于运动员钙损失和骨密度的研究发现，在一个赛季中，男性大学篮球运动员的总BMD大幅下降。当在接下来的竞争赛季以CA体育饮料的形式给予同一名运动员的补充CA时，BMD而不是损失有所增加。 为了进一步探索钙通过汗水损失的潜在作用，我们选择在竞争性的公路骑自行车的人中进行研究。 他们的高训练量（10-15 h/wk或更多）预计将产生较大的汗水CA损失。同样，道路骑行的训练/竞争季节相对较长（1月至9月），这适合确定对骨代谢的影响。 我们选择学习公路骑自行车的人的另一个原因是，他们似乎有低BMD的风险增加。6-12 我们将在这项试验研究中通过汗水研究钙的损失，这是BMD损失的一种潜在机制。 但是，还发现剧烈运动会破坏人类的性别和压力激素水平。13-16剧烈运动也可能导致全身性炎症。17-19这些改变也可能影响骨代谢。 目的和假设： 这项试验研究的主要目的是以一种潜在的，受控的方式评估一种潜在的机制，通过这种机制，剧烈的运动（无论是在运动的长度和训练/竞争季节的长度而言）都可以促进骨质流失。 我们的假设如下： H1：长期，剧烈的运动训练导致的皮肤CA损失是在训练和竞争季节中竞争性公路骑自行车者骨丢失的重要决定因素。 H2：将CA摄入量增加到当前推荐的水平（2000 mg/d）将减轻训练和竞争季节竞争性公路骑自行车者的骨骼损失。 方法： 为了解决这些假设，我们将在一个训练和竞争季节中研究20名竞争骑自行车的人。 参与者将是18-35岁的男性，他们已经参加了2个或更多赛季的比赛，并且每周训练10个或更多小时。 他们的基线钙摄入量或低于建议的每日1000毫克/天的津贴。 它们将被随机分配为安慰剂或补充钙，至1800-2000毫克/天或保持其通常的1000-1200mg/天摄入量。 参与者将在基线，赛季中期和赛季结束后，在固定的教练进行2小时的模拟训练。 BMD将在这些访问时测量，其汗液损失的估计将通过测量汗液钙浓度和确定汗液损失来确定（根据校正水量和尿液产生的体重的变化估算）。 分析： 我们的主要结局指标是安慰剂不补充与钙补充组中的BMD。 我们将尝试控制混杂因素，例如性别和压力激素，炎症制造商的变化以及整个季节的体重变化。