View clinical trials related to Energy Supply; Deficiency.
Filter by:This randomized crossover study will examine the effects of consuming isocaloric GLU+FRU or GLU alone on rates of exogenous carbohydrate oxidation during aerobic exercise and physical performance (time trial) under energy balance (BAL) and energy deficit (DEF). Baseline data will be collected on volunteer height, weight, body composition, and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. To start the protocol volunteers will complete a bout of glycogen normalization on a cycle ergometer followed by 48 hours of refeeding at 100% (BAL) or 50% (DEF) of their energy needs. After the 48 hours of refeeding volunteers will return to the laboratory to complete 80 min of steady-state (60 ± 5% V̇O2peak) exercise on a cycle ergometer. Immediately before and during steady-state exercise, volunteers will consume either 80 g of GLU+FRU (53 g glucose + 27 g fructose) or 80 g GLU. Drinks containing corn-derived crystalline fructose (KRYSTAR® 300, Tate and Lyle Sugars, London, UK) and glucose (CERELOSE®, Ingredion, Westchester, IL, USA) will be prepared by unblinded USARIEM staff. Drinks will be enriched with 13C stable isotopes (Cambridge Isotope Laboratory, Andover, MA, USA) to measure exogenous and plasma carbohydrate oxidation during steady-state exercise. After steady-state exercise, physical performance will be assessed using a graded exercise test on a stationary bike. Indirect calorimetry and breath sampling will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess isotope enrichments, and circulating substrate/hormone responses. Muscle biopsies will be performed before and after steady-state exercise to assess glycogen status, enzyme activity, and molecular regulation of substrate metabolism. There will be a minimum of 7 days between each carbohydrate metabolism study day.
This study aims to establish the metabolic/molecular response in both adipose tissue and skeletal muscle as well as sensory experiences (pain, fatigue, drive) to prolonged fasting of 3 days duration. Participants will undergo sequential meal assessment before and after a 3 day fast with measures taken throughout each fasting day.
Using a randomised crossover design, nine weight-stable men, aged 18 - 40 years old, will be recruited via convenience sampling from the staff and student body of LJMU and local area. Participants will be asked to follow two 4-day (~96 hours) periods of tightly controlled exercise energy expenditure (15 kcal/kg FFM/day [cycling]) and dietary intake (60 kcal/kg FFM/day) to compare a state of 'normal' energy availability (or energy balance; equivalent to 45 kcal/kg FFM/day) with concomitant 1: normal carbohydrate availability ('Normal'; ~60% of dietary intake from carbohydrate) and 2: low carbohydrate availability ('LCHF', ~1.5 g/kg carbohydrate per day, ~70 - 80% dietary intake from fat). This approximates the amount of carbohydrate consumed by an individual in a state of LEA through consuming 10 kcal/kg FFM/day with 50% of intake from carbohydrate, or ~1.5 g/kg/day of carbohydrate. In both experimental phases we will measure endocrine, metabolic and physiological parameters.
This study aims to examine the effects of Sourse's Hype Bites at being able to increase vitamin B12 levels to promote positive health outcomes. Participants will consume Hype Bites daily. Participants will also take surveys and blood samples to examine both the subjective experience of taking Hype Bites as well as changes in biomarkers across the trial.
10 healthy, male, participants will complete a a 5-day baseline assessment (days -5 to -1) and two consecutive 5-day periods of controlled exercise to increase oxidative capacity (3 days of aerobic exercise per period, 15 kcal/kg FFM/day energy expenditure cycling) and energy intake (15 days in total, with a testing session on morning 16). This will achieve states of energy balance (EB; energy availability - EA - 45 kcal/kg of fat free mass (FFM)/day), required for weight maintenance (days 1 - 5), followed by energy deficit (ED; EA 10 kcal/kg FFM/day), required for weight loss on days 6 - 10. Over the data-collection period, participants will consume deuterium (D2O) tracer to facilitate dynamic proteomic profiling to assess the impact of the intervention on muscle quality (primary outcome measure). Muscle biopsies will therefore be collected on days -5, 1, 6 & 11, alongside daily saliva samples, and venous blood collection on days -5, 1, 3, 5, 6, 8, 10 & 11. These samples will be used to assess further, secondary, outcome measures including alterations in intra-muscular lipid profiles (lipid droplet content, morphology and lipid-droplet associated proteins in different subcellular compartments [intermyofibrillar vs subsarcolemmal]), alterations in blood metabolites and hormones and skeletal muscle glycogen concentrations. Changes in body mass, body composition and RMR will also be assessed.
This randomized, parallel study will examine the effects of energy balance and varying magnitudes of energy deficit on 1) the protein kinetic responses to consuming high quality protein and 2) carbohydrate oxidation during steady-state exercise. Healthy adults, representative of active duty military personnel, will complete a 2 d energy balance phase followed by a randomly assigned, 5 d energy deficit phase (n=15 per group; 20%, 40% and 60% energy deficit). At the end of each energy phase the effects of energy balance and energy deficit severity on resting postabsorptive (fasting) and postprandial (after consuming ~34 g protein) muscle protein synthesis (MPS) and whole-body protein synthesis, breakdown, and balance (synthesis - breakdown) will be determined. On the next day, the effects energy balance and energy deficit severity on carbohydrate oxidation during steady-state exercise will be determined. Primary study procedures include anthropometric and body composition measures, resting metabolic rate measures, aerobic exercise, tightly controlled diet and exercise interventions, repeated blood sampling, stable isotope infusion, stable isotope ingestion, and percutaneous muscle biopsies. The following hypotheses will be tested: 1) Δ (postprandial - postabsorptive) MPS and Δ whole-body protein balance at rest will progressively decrease as magnitude of energy deficit increases and 2) exogenous carbohydrate oxidation will be higher and endogenous carbohydrate oxidation will be lower during steady-state exercise as magnitude of energy deficit increases.
The study team will examine the effect of a ketogenic diet alone and ketogenic diet supplemented with oral ketones on how the body of individuals with type 2 diabetes respond to insulin, regulates insulin secretion, food intake and energetic pathways and influences body fat distribution.
Osteoporosis is worldwide health epidemic categorized by poor bone health, primarily diagnosed by low bone mineral density, and costs healthcare systems billions every year. Athletes and exercising people who expend large amounts of energy in physical activity, or restrict diet in order to lose weight, are at risk of low energy availability. This is when an individual fails to match their exercise energy demand with a appropriate dietary intake in order to maintain optimal physiological function; which can lead to low bone mineral density, osteoporosis both early and later in life and an increased risk of injury. Runners are particularly susceptible to stress fracture in response to low energy availability due to repetitive ground impact. Research shows that as little as five days low energy availability significantly reduces bone formation, and significantly increases bone resorption, in physically active women. The ideal solution is to restore energy availability; however, this is often very difficult during periods of intense training and conflicts with the goal of weight loss. Therefore, there is a need to develop an alternative tool to protect bone health. It is critical that any exercise intervention does not further reduce energy availability as previous research shows that this accelerates bone loss rather than prevents it. Low repetition high impact jumping exercise is highly beneficial to bone health and has been shown to improve bone structure when used as a long-term intervention in energy replete states. It takes very little time to complete and uses a very small amount of energy. However, no study to date has examined the effects of such an intervention during low energy availability. The current study will investigate whether low repetition high impact jumping prevents or reduces the reduction in bone formation and the increase in bone resorption experienced during five days of low energy availability and findings will have implications on athletic and recreational training recommendations in order to protect bone health.
Exercise is an important factor in bone health. Sclerostin is one of the key molecules involved in bone response to mechanical loading. In particular, sclerostin decreases bone formation directly through the inhibition of Wnt/ β-catenin signaling and increases bone resorption indirectly via upregulation of the RANK/RANKL. The Wnt pathway is an anabolic signaling pathway, which leads to the activation of osteoblasts. OPG is another osteokine secreted by osteoblasts and osteogenic stomal cells that has a protective osteogenic role in humans by inhibiting the binding of RANKL to its receptor RANK. The RANK/RANKL pathway is a catabolic signaling pathway controlling osteoclast differentiation. Only a few studies have examined the effects of one single bout of high impact exercise on serum sclerostin levels in adults, most of which are from the investigators' lab. However, not many studies have examined the acute effects of moderate intensity, low-impact exercise on osteokines of the Wnt signaling. Previous studies have only investigated the impact of high intensity cycling on sclerostin, OPG and RANKL, however, no research has been done to investigate the response of osteokines to moderate intensity continuous cycling. This study aims to investigate differences in osteokines and markers of bone turnover following three moderate intensity cycling trials of different duration (30, 60 and 120 min) in an energy replete state. The question we aim to answer is whether there is a threshold of time where continued stimulus from moderate strain on the bone fails to elicit an additional metabolic response in bone or even becomes osteocatabolic, when athletes are in an energy replete state. Additional biochemical responses to the exercise will also be examined including inflammatory markers, glucose, anabolic/hormonal markers and oxidative stress.
Low energy availability (LEA) is a major problem in sports as athletes ingest often a lower amount of energy compared to their actual needs. The availability of energy is calculated based on their daily energy intake and the energy cost of the daily training sessions in relation to their fat-free mass. Based on this calculation, it is known how much energy will available for the body (beside the fuel for training) to keep it in optimal physiological functioning. It has been shown, that LEA occurs very often in female athletes, in endurance athletes as well as athletes in weight-sensitive sports (i.e. jockeys, combat sports, gymnastics, ballet). The purpose of this study was to investigate, whether LEA is a problem in wheelchair athletes as well.