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Do pre-workout supplements affect resting vascular function?


OBJECTIVE

The use of dietary sport supplements to enhance performance and body composition has recently been popular among active individuals, especially pre-workout supplements. Pre-workout supplements have gained attention with a purpose of augmenting physiological improvements associated with resistance training, for example, increasing lean muscle mass, while maintaining or improving perceived energy, concentration, strength, and power. However, some of the effects of these supplements on the cardiovascular function remains understudied. With regards to pre-workout supplementation, the authors suggest there is a critical need to determine the effects on vascular function following acute resistance exercise given that events of temporary reduced flow-mediated dilation in the post-exercise period has previously been reported.

Therefore, the purpose of this study was to assess the effects of a multi-ingredient dietary pre-workout supplement on cardiovascular function at rest, and immediately following an acute leg press resistance exercise in healthy recreational active individuals.


WHAT THEY DID

12 participants (9 males, 3 females) volunteered to a double-blind, randomised, cross-over study design. Following familiarisation, participants were randomly placed to either a placebo (PLA) or pre-workout supplement (SUP) group. Participants were instructed to consume one serving of the supplement (Iron Pump, Arnold Schwarzenegger series MusclePharm Corp) or the PLA every day at preferred time for one week preceding the experimental tests. There was a two-week washout period for men and one-month for the women. Females were tested within the first days of the follicular phase of their menstrual cycle (self-reported information). In the tests, participants completed measures of vascular function. This involved peripheral measures of blood pressure and branchial artery flow mediated dilation followed by measures of arterial stiffness via pulse wave analysis and pulse wave velocity. These measurements were taken at both rest, and immediately following eight sets of 10 repetitions at ~80% 1RM of bilateral leg press with two-minute rest in between the sets.


WHAT THEY FOUND

Findings showed no significant differences in resting and post-exercise blood pressure, and in brachial artery flow mediated dilation and arterial stiffness between PLA and SUP. This study, therefore, concluded that one week of multi-ingredient pre-workout supplement did not adversely affect cardiovascular responses at rest or to an acute bout of resistance exercise in young, healthy recreational individuals.


Practical Takeaways

It is well-known that sport supplements are prevalent in the athletic populations in order to peak performance. Whilst pre-workout supplements are common in recreationally active individuals (i.e. engage in exercise multiple times per week), this supplement may not be appropriate to professional athletes. Given that Iron Pump, Arnold Schwarzenegger series MusclePharm Corp suggests many benefits to users, there may also be a risk of harm for the athlete if an anti-doping rule violation surfaces. This is likely to occur if supplements contain traces of banned substances due to contamination, and therefore, it is extremely important that athletes only use supplements that are trusted by registered testing facilities to avoid an anti-doping violation (i.e. batch-tested supplements).

Athlete support personnel and SENr nutritionists should be consulted before professional athletes implement such a supplement into their regime. It is also important that the practitioner encourages a “food first” policy at all times, with multi-ingredient pre-workout supplement with additional micronutrients (e.g. caffeine and nitrates) only utilised if completely necessary to support the athlete during intense training regimens. This multi-ingredient pre-workout appears to have no negative impact on cardiovascular function at rest or post-exercise in recreational athletes, however, it is advised that the professional athlete should use other types of provision of energy (e.g. a strong coffee, if needed). Inadvertent consumption of prohibited substances under the anti-doping codes that govern elite sport is a known risk of taking supplements ( please see attached video ) .



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