American researchers investigate the acute effects of multi-ingredient pre-workout supplements on energy and endurance in active females.
Exercise performance-enhancing dietary supplements have been used for athletes and regularly active individuals in the past, but now a new category of dietary supplements has emerged. Referred to as multi-ingredient pre-workout supplements (MIPS), this new supplement has gained the attention of active individuals due to claims such as increased focus, blood flow, and energy when taken before a workout.
Pre-workout supplements may contain any combination of various compounds such as caffeine, creatine, taurine, and glutamine among others. These blends are manufactured for prolonged use that can lead to enhanced training adaptations the longer it is used. A recent study published in the Journal of the International Society of Sports Nutrition examined the acute effects of pre-workout supplements on resting metabolism and exercise performance in recreationally-active females.
The study tracked 15 recreationally-active females, between the ages of 19 to 23 years, in a randomized, double-blind, placebo-controlled study. A physical health and biometric baseline were completed as well as two experimental testing sessions, which assessed resting energy expenditure, heart rate, and blood pressure following the ingestion of either a pre-workout supplement or a placebo. The researchers took subjective measurements of energy and focus using an established 5-point scale. The subject testing took place within seven days of completing their baseline to maintain accuracy for the two experimental workout sessions to follow. The scientists used a two-day dietary log to assess the differences in total macronutrient intake during the days prior to each testing session to ensure that the session results were not influenced by dietary intake. Finally, the subjects were questioned about their feelings of focus, energy, and fatigue immediately following the physical tests using a five-point scale.
Pre-workout Supplements Improved Performance
The results demonstrated the efficacy of pre-workout supplements and showed acute increases in resting energy expenditure for up to 60 minutes. They also found that the consumption of a multi-ingredient pre-workout supplement increased resting metabolism and increased diastolic blood pressure. Upper body muscular endurance and anaerobic capacity were improved and females noted higher levels of focus proceeding high-intensity exercise. The participants who ingested the supplements performed better on bench press and treadmill activities.
Side Effects: Those with Heart Disease Should Use Caution
The researchers did not find any negative effects of the supplement on the heart rate or systolic blood pressure of the participants. However, the side effects of the pre-workout supplements included flushing of the face, tingling hands, and a jittery sensation. These side effects are not uncommon for the consumption of caffeine, a key ingredient in the blends. The increase in diastolic blood pressure, however, indicates that individuals with risk factors for cardiovascular disease should exercise caution before using these types of supplements.
The strengths of this study lie in the fact that most research concerning pre-workout supplements thus far has focused primarily on males, while this study examined the effects in females. The mental clarity and physical boost associated with pre-workout supplements can be used to further improve the quality of a training session but additional research is needed to examine the long-term effects of these supplements.
Written by Cooper Powers, BSc
Reference: Cameron, M., Clayton, L.C., Doberstein, S., Erickson, J., Jagim, A. (2018). The acute effects of a multi-ingredient pre- workout supplement on resting energy expenditure and exercise performance in recreationally active females. Journal of the International Society of Sports Nutrition, 15(1). DOI 10.1186/s12970-017-0206-7