The Effects of Pre-Loaded Betaine Supplementation on Thermoregulation and Exercise Metabolism in the Heat
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 14
- 试验地点
- 2
- 主要终点
- Thermoregulation (enzyme linked immunoassays)
研究概览
简要总结
This will be a double blind, placebo-controlled, randomized, counterbalanced, crossover study designed to assess the impact of preloaded betaine supplementation on thermoregulation and exercise metabolism in the heat. The study, outlined in Figure 7 and described in detail below, will consist of seven total visits to the Institute of Sports Science and Medicine (ISSM) or Sandels laboratories at Florida State University, two of which will be experimental visits. On the first visit, participants will be informed as to the details of the study before giving their oral and written informed consent (Appendix A). Thereafter, anthropometrics will be measured and participants will complete an incremental exercise test on an electronically-braked cycle ergometer to volitional exhaustion to determine peak oxygen consumption (VO2 peak). Days 1-6 participants will consume a full dosage of supplementation, whereas day 0 and 7 participants will consume half a dose of the supplement, with the last dosage being consumed 60 minutes prior to experimental visits, days 7 and 21. On days 2 and 4, familiarization trials will be completed to standardize training loads and to reduce any potential learning effect. These visits will be implemented in the heat. On day 7, participants will complete the first experimental trial described in detail below. Afterwards, participants will enter a seven day washout period 167 before crossing over to the second supplemental condition on day 14. On days 16 and 18, participants will undergo the same familiarization trials as they did on days 2 and 4. On day 21, participants will complete their second experimental trial. Each experimental trial will be separated by 14 days. This study will be approved by the Florida State University Insitutional Review Board (Appendix B).
详细描述
Initial Visit Participants will be asked to come into the ISSM in the morning, following an overnight fast (7-9 hr) having abstained from caffeine for the previous 12 hours, and having abstained from alcohol and exercise for the previous 24 hr. Participants will be asked to consume 6 ml·kg-1 water 60 minutes prior to arrival. Following the signing of the informed consent document, participants will be asked to change into athletic clothing. Thereafter, with shoes removed, participants' height will be assessed to the nearest cm via a wall-mounted scale (Seca, Hamburg, Germany). Participants will be weighed to the nearest 0.1 kg via an automated scale (Detecto® 750, Webb City, MO). Body composition will then be assessed via Bod Pod (Cosmed, Chicago, IL). Participants will be asked to rest quietly in a supine position for 5 minutes, before blood pressure will be measured via auscultation and sphygmomanometry (Grainger, Lake Forest, Illinois). While still in a supine position, fluid compartments will be measured via bioelectric impedance spectroscopy (BIS) (ImpediMed SFB7, ImpediMed Limited, Australia).
Following these baseline measurements, participants will be asked to wear a heart rate monitor then complete a self-determined 5-min warm-up on an electronically-braked cycle ergometer (Velotron, SRAM, Spearfish, SD). Immediately after the warm-up, participants will be fitted with a metabolic mask (TrueOne 2400 Metabolic Cart, ParvoMedics, Sandy, Utah) then commence an incremental exercise test to exhaustion. The incremental test will consist of 3-min stages in which the resistance will begin at a relative intensity of 2 W·kg-1 and increase in 25 W increments until RER is greater than 1.0. At this point, the test will switch to 1-min stages with resistance increasing in 10 W increments until volitional exhaustion. A similar protocol is described elsewhere 223.
Afterwards, participants will be provided with their blinded supplement and instructed to consume 50 mg·kg-1 twice daily (~12 hr apart) with 6 ml·kg-1 water each time, for 7 days.
Familiarization Trials The familiarization trials will occur the first week of supplementation on days 2 and 4, and the second week of supplementation on days 16 and 18. On familiarization days, participants will be asked to arrive at the Sandels building in the morning in a euhydrated state, having consumed 6 ml·kg-1 water 60 minutes prior to arrival. Additionally, participants will be asked to arrive following an overnight fast (7-9 hr) having abstained from caffeine for the previous 12 hours, and having abstained from alcohol and exercise for the previous 24 hr. Upon arrival, the participant will be fitted with a heart rate monitor (Polar® FT4M, Sempele, Finland). Participants will enter the chamber (33° C, 35% RH), be fitted with a metabolic mask (TrueOne 2400 Metabolic Cart, ParvoMedics, Sandy, Utah) and cycle for 30 min at 70% VO2 peak. After a 5 min active recovery period, self-paced pedaling against 50 W, participants will perform four 12 s maximal effort sprints against 5.5% of their body mass, followed by one 30 s maximal effort sprint against 5.5% of their body mass. Participants will perform 2.5 min active recovery (self-paced pedaling against 50 W) between sprints. Participants will then exit the chamber and be allowed to drink ad libitum in a resting position.
Experimental Trials This section provides an overview of the experimental trials, with greater detail provided in the appropriate sections below.
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
- Triple (Participant, Care Provider, Investigator)
入排标准
- 年龄范围
- 18 Years 至 45 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Age: 18-45 yr
- •Trained male cyclists: ≥ 3 yr cycling experience
- •Participants' VO2 peak > 50.0 ml·kg·min-1
排除标准
- •Sex: female
- •Age: < 18 yr or > 45 yr
- •Cigarette smoking: current cigarette smoker or those who quit within the previous 6 months
- •Participants' VO2 peak < 50.0 ml·kg·min-1
- •Participants consuming supplements known to impact hydration status and exercise performance
- •Participants known to have sickle cell trait or disease
结局指标
主要结局
Thermoregulation (enzyme linked immunoassays)
时间窗: 7 days of supplementation & minutes 0, 30, 60, and 90 during the experimental visit
serum expression of heat shock protein 72 and plasma lipopolysaccharide concentrations
Thermoregulation (thermal sensation scale)
时间窗: minutes 0, 15, 30, 45, 60, 75, and 90 during the experimental visit
Subjective self-reported assessment of perceived thermal sensation (arbitrary units)
Thermoregulation (core temperature pills, skin temperature sensors)
时间窗: pre and post 7 days of supplementation & minutes 0, 15, 30, 45, 60, 75, and 90 during the experimental visit
Core temperature (Degrees C), skin temperature (Degrees C)
Fluid Compartment Volumes (Bioelectrical Impedance Spectrocopy)
时间窗: pre and post 7 days of supplementation
Intracellular fluid volume (L), extracellular fluid volume (L), plasma volume (L), total body water (L)
次要结局
- Exercise Metabolism and Performance (Oxygen Consumption)(minutes 0-5, 25-30, and 55-60 during the experimental visit)
- Exercise Metabolism and Performance (heart rate)(minutes 0, 15, 30, 45, 60, 75, and 90 during the experimental visit)
研究者
Michael J. Ormsbee
Principal Investigator
Florida State University