Study on Effects of High-Fat Versus High-Carbohydrate Bars on Exercise Performance During Cold Exposure for Adults Aged 18 to 39

What this Trial Is About

Researchers are studying how different types of energy bars affect the bodys use of fuel and aerobic performance during cold weather exposure. This randomized crossover study focuses on healthy adults aged 18 to 39 years who perform exercise in a cold environment 5C while wearing light clothing. The goal is to understand how bars higher in carbohydrate or higher in fat impact energy use and endurance during cold-weather military operations. Participants consume one of two types of isocaloric supplement bars approximately 350 kcal one higher in carbohydrates 50% carbs, 30% fat, 20% protein or one higher in fat 30% carbs, 50% fat, 20% protein. The order of consumption is randomized and double-blinded. After consuming the bar, volunteers rest for 60 minutes in cold conditions, then perform 90 minutes of treadmill exercise carrying a load equal to 30% of their body weight. This is followed by a 2-mile time trial to assess endurance performance. There is a minimum washout period of six days between trials. During the study, researchers collect baseline data height, weight, body composition, peak oxygen uptake and monitor core and skin temperatures continuously. Indirect calorimetry is used to measure substrate oxidation during exercise, and serial blood samples assess circulating substrates and hormones. Exercise and diet are controlled, including a lead-in diet 24 hours before each trial. The study measures endurance performance over 30 minutes and substrate oxidation over 90 minutes. Participants are asked to abstain from alcohol, nicotine, and other supplements during the study periods.

Energy Dense Fueling for Cold-Weather Operations