Caffeine Ingestion With or Without Low-Dose Carbohydrate Improves Exercise Tolerance in Sedentary Adults

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry

Background:

• Caffeine and carbohydrate (CHO) ingestion are known ergogenic aids for endurance-trained (ET) athletes.
• Their effectiveness in sedentary (SED) adults remains less documented.

Purpose of the Study:

• To investigate the ergogenic effects of caffeine and low-calorie carbohydrate (LCHO) on exercise tolerance in age-matched sedentary and endurance-trained adults.
• To compare the efficacy of caffeine alone, LCHO alone, and a combination of caffeine and LCHO against a placebo.

Main Methods:

• A double-blind, crossover design was employed with 12 sedentary and 12 endurance-trained participants.
• Participants completed cycling trials including a standardized moderate-intensity exercise followed by a time to fatigue at a higher intensity.
• Ingested treatments included caffeine (3 mg/kg), LCHO (0.4% solution), caffeine + LCHO, and placebo.

Main Results:

• Caffeine treatments (alone and combined with LCHO) significantly reduced perceived exertion and increased time to fatigue compared to no-caffeine treatments for all participants.
• Low-calorie carbohydrate (LCHO) alone did not improve exercise tolerance compared to placebo.
• Caffeine ingestion elevated blood glucose and lactate levels, with ET individuals exhibiting higher fat oxidation rates than SED individuals.

Conclusions:

• Caffeine ingestion enhances exercise tolerance and reduces perceived exertion in both sedentary and endurance-trained individuals.
• The ergogenic benefits of caffeine were not further augmented by the co-ingestion of low-calorie carbohydrates.
• Sedentary adults can experience performance improvements with caffeine, similar to trained athletes.