Creatine Loading Induces Reductions in Cortisol Levels at Rest & Post Workout, As Well As Improvements in Glucose Managament in Swimmers During High Intensity Training

If you are already taking creatine today's SuppVersity article is just a reminder to make sure not to run out. If you are not, the anti-glucocorticoid effects of creatine are another reason to start.

It has been a while since the last SuppVersity creatine article saw the light of the day (read previous ones). No wonder. I mean, we already know everything about the "nitrogenous organic acid that occurs naturally in vertebrates and helps to supply energy to all cells in the body, primarily muscle," (Wikipedia) don't we?

We know that the ergogenic effects are a result of an increased formation of the super fast energy reservoirs in our muscular phosphocreatine pools and we are well aware that the use of creatine (monohydrate is the only proven ergogenic, by the) to increase strength and size gains is supported by several dozens of studies from reputable Universities.
What you maybe didn't know yet is that creatine will also affect the activity of your adrenal glands after exhausting workouts like the one seventeen swimming athletes were subjected to in a recent study from the Federal University of Paraná (UFPR) in Brazil.

The participants were swimming athletes (competitors under master or professional levels) from various swimming centers in the city of Curitiba/Pr-Brazil as well as swimming athletes not associated with swimming centers. They had performed their swim training for a period of at least five years and were currently attempting to improve swim speed at a training frequency of at least four days per week. To elucidate if they'd benefit to a similar extend from the provision of extra creatine as the strength trainees in the previously cited studies, the participants were randomly assigned to receive either

• 20g creatine and 1g/kg body weight of maltodextrin per day
• No creatine, just 1g/kg body weight of maltodextrin per day

The participants ingested the sports supplements in four equal doses throughout the day, with one of the doses taken 40 minutes prior to the swim-protocol on the day of testing.
The supplementation was initiated six days prior to the progressive swim protocol, which consisted of eight consecutive 100-meter freestyle sets that were performed in a progressive intensity format in the following manner:

• 3 sets at 65% of the best 100 meter time with 3 minutes of rest after each set
• 2 sets at 75% of the best 100 meter time with 4 minutes of rest after each set
• 1 set at 85% of the best 100 meter time with 6 minutes of rest after this set
• 1 set at 95% of the best 100 meter time with 20 minutes of rest after each set
• 1 set at maximum intensity (100% effort)

Percentages of effort were established according to the best times recorded for each athlete, which were obtained during an initial visit to the MobiDick Sport Center. Blood samples were taken before and after the trials.

Figure 1: Blood cortisol concentrations at day 0 and day 6 (before and after supplementation) at rest and immediately after the workout in swimming athletes consuming 1g/kg body weight malto +/- 20g creatine per day (Dobgenski. 2014)

If you take a look at what the analyses of the subjects' blood revealed, you will see that the post-workout cortisol concentrations were significantly decreased (p < 0.05) in the creatine + maltodextrin group - surprisingly, however, they were reduced not just in comparison to the placebo, but also in comparison to the baseline values.

Don't forget: Cortisol is a glucocorticoid, not a muscle killer!

Within the fitness and bodybuilding community cortisol is often looked down upon as the "bad catabolic hormone that gnaws on your muscles". In reality, cortisol is rather the good glucocorticoid that ensures that your brain has enough fuel all the time (learn more), even if this means that you have to sacrifice some muscle tissue to use the protein to make glucose in the liver (gluconeogenesis).

Figure 2: Insulin and glucose levels at rest and PWO before and after the intervention (Dobgenski. 2014)

Against that background it's not surprising that the low cortisol levels in the creatine group went hand in hand with significantly lower blood glucose and insulin levels at rest and non-significantly lower blood glucose levels after the workout.
In their discussion of the results, the authors also highlight that cortisol exerts its catabolic activity by inducing lipolysis and proteolysis (fat and amino acid breakdown) in order to fuel hepatic gluconeogenesis (the formation of glucose from fat and amino acids in the liver) and increases systemic blood glucose concentrations. Usually, that means in previous studies, the provision of carbohydrates was sufficient to blunt the cortisol-increase during exercise. In this study with a significantly more intense non-endurance type of activity, however, the increases in cortisol in response to the 'beneficial stressor' (i.e. the high intensity swimming protocol in the study at hand) could not be blunted by the ingestion of 1g/kg maltodextrin. Only the ingestion of creatine and thus the increase of the phosphocreatine stores your body relies on, when you're exercising at high intensities did the trick.

Now, this raises the question if creatine loading in the classic sense of taking 20g+ of creatine is necessary to see these results. Initial studies on the use of creatine monohydrate as ergogenic agent suggested just that. Later, however, scientists realized that it is rather a matter of dosage and time period. In other words, if you take 20g everyday you can top off your PCr stores within a single week and week them well stocked by taking 3-5g over the following weeks and months. According to more recent studies, similar ergogenic effects can be achieved with much lower doses if those are ingested over longer time periods (e.g. 2.3g/day over 6 weeks in Rowson. 2011) - in the absence of the usual water bloat you'd see if you take 20g or more per day!
References:

• Dobgenski, V., Santos, M. G. D., Campbell, B., & Kreider, R. (2014). Short-term creatine supplementation suppress the cortisol response to a high-intensity swim-sprint workout. J Nutr Health, 1(204), 8-10.
• Gleeson M, Nieman D.C, Pederson BK (2004) Exercise, nutrition, and immune function. J Sports Sci 22: 115-25.
• Hoffman, Jay R., et al. "Effect of low-dose, short-duration creatine supplementation on anaerobic exercise performance." The Journal of Strength & Conditioning Research 19.2 (2005): 260-264.
• Li TL, Gleeson M (2005) The effects of carbohydrate supplementation during the second of two prolonged cycling bouts on immunoendocrine responses. Eur J Appl Physiol 95: 391-9. 
• Rawson, Eric S., et al. "Low-dose creatine supplementation enhances fatigue resistance in the absence of weight gain." Nutrition 27.4 (2011): 451-455.
• Shao, A., & Hathcock, J. N. (2006). Risk assessment for creatine monohydrate. Regulatory Toxicology and Pharmacology, 45(3), 242-251.
• Theodorou, A. S., Havenetidis, K., Zanker, C. L., O'Hara, J. P., King, R. F., Hood, C., ... & Cooke, C. B. (2005). Effects of acute creatine loading with or without carbohydrate on repeated bouts of maximal swimming in high-performance swimmers. The Journal of Strength & Conditioning Research, 19(2), 265-269.
• Walker G.J, Finlay O, Griffiths H, Sylvester J, Williams M, et al. (2007) Immunoendocrine response to cycling following ingestion of caffeine and carbohydrate.
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