Dose-Response Effects of Short-Term Ashwagandha on Anaerobic Exercise and Cognitive Function in Resistance-Trained Athletes

Ashwagandha (ASH) is an herbal supplement derived from the Withania somnifera plant. It is commonly described as an adaptogen, a substance thought to help the body cope with physical and psychological stress. Previous research has examined ashwagandha supplementation using different doses and supplementation periods. This study examined the effects of seven days of supplementation on muscular strength, exercise performance, cognitive function, and selected physiological measures in healthy, resistance-trained men and women. It also examined whether these effects differed between low and high doses. The study used a crossover design in which each participant completed four conditions: no supplementation, a placebo containing maltodextrin, low-dose ashwagandha at 4 mg per kilogram of body weight per day for seven days, and high-dose ashwagandha at 14 mg per kilogram of body weight per day for seven days. The three supplementation conditions were separated by seven-day washout periods. During the blinded supplementation conditions, neither the participants nor the researchers conducting the assessments knew which supplement was being administered. At the end of each seven-day supplementation period, participants completed laboratory assessments. These included the maximum weight lifted for one repetition on the bench press and leg press, total lifting volume across multiple sets, and the speed and power of bar movement. Participants also completed a 30-second all-out cycling sprint to assess anaerobic power, total work, and fatigue, along with a color-word test to assess cognitive performance. Additional assessments included resting energy expenditure, heart rate, blood pressure, perceived exertion, self-reported readiness, focus, alertness, and selected blood markers related to cholesterol, liver function, and muscle damage.

Inclusion Criteria: * Age 18-40 years * At least 2 years of regular resistance training that included the bench press and either the leg press or squat * Body mass index (BMI) of 18.5-24.9 kg/m² Exclusion Criteria: * Age under 18 years and above 40 yrs * A history of treatment for metabolic disease (e.g., diabetes), hypertension, hypotension, thyroid disease, arrhythmias, and/or cardiovascular disease * Current use of any prescription medication * Intolerance to natural stimulants * A history of smoking * Excessive drinking (12 drinks per week) * Known allergy to ashwagandha, as this could affect the participant's safety and the study's outcomes