DIETARY CARBOHYDRATE REQUIREMENT IN YOUNG, HEALTHY WOMEN

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定为研究者机构。虽然运动提供了不可否认的健康益处，但在越来越多的参加体育训练的妇女中，饮食失调、闭经和骨质疏松症的发病率很高。闭经，即月经周期停止连续三个月以上，据推测影响了高达44%的女运动员。在这种情况下，雌二醇分泌不足会导致骨矿物质密度降低，并增加骨折、骨质疏松症和心脏病的风险。闭经运动员的骨骼肌磷酸肌酸酐恢复时间也较长，这表明他们进行重复运动的能力受损，与他们经常锻炼的竞争对手相比，他们处于竞争劣势。以前，我们表明，4天的低能量可用性（EA=控制能量摄入减去控制运动能量消耗），但不是运动的压力，似乎减少LH脉冲频率和24小时的平均值和幅度的昼夜节律的瘦素在年轻，健康，妇女。最近在其他哺乳动物中的证据表明，低碳水化合物可用性，而不仅仅是低能量可用性，导致生殖功能障碍，并可能调节瘦素水平。然而，在人类中的控制实验是缺乏的。了解碳水化合物对LH脉动性和昼夜瘦素节律的短期影响对于制定营养指南以保护运动员和其他体力活动女性的生殖，骨骼和心血管健康至关重要。建议的随机重复测量实验旨在评估碳水化合物可用性（定义为控制饮食碳水化合物摄入量减去控制运动碳水化合物消耗量）和能量可用性对年轻健康女性LH脉动、昼夜瘦素节律和其他代谢激素和底物调节的独立影响

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. While exercise provides undeniable health benefits, a high incidence of disordered eating, amenorrhea and osteoporosis occur among the increasing numbers of women participating in athletic training. Amenorrhea, the cessation of menstrual cycles for more than three consecutive months, has been postulated to affect up to 44% of women athletes. Hyposecretion of estradiol in this condition causes a loss of bone mineral density and an increased risk of fractures, osteoporosis and heart disease. Amenorrheic athletes also have a prolonged skeletal muscle phosphocreatinine recovery time, suggesting an impaired ability to perform repeated bouts of exercise and a competitive disadvantage compared to their regularly menstruating competitors. Previously, we showed that 4 days of low energy availability (EA=controlled energy intake minus controlled exercise energy expenditure), but not the stress of exercise, appeared to reduce both LH pulse frequency and the 24h mean and amplitude of the diurnal rhythm of leptin in young, healthy, women. Recent evidence in other mammals suggests that low carbohydrate availability, and not simply low energy availability, causes reproductive dysfunction and may regulate leptin levels. However, controlled experiments in humans are lacking. Understanding the short-term effects of carbohydrate availability on LH pulsatility and the diurnal leptin rhythm is critical in the development of nutritional guidelines for the protection of reproductive, skeletal and cardiovascular health in athletes and other physically active women. The proposed randomized repeated-measures experiment is designed to assess the independent effects of carbohydrate availability, defined as controlled dietary carbohydrate intake minus controlled exercise carbohydrate expenditure, and energy availability on the regulation of LH pulsatility, the diurnal leptin rhythm, and other metabolic hormones and substrates in young, healthy women