Compared to their previous findings showing that a higher single dose of 0.35 g/kg creatine had positive effects on cognition during sleep deprivation, the researchers noted that the more pronounced effects were not observed in short-term memory tasks or processing speed, but in other domains, particularly logic tasks.
“Our results emphasize that the effects of creatine on short-term memory appear to be dose-dependent,” the researchers in Germany wrote in Nutrients.
Creatine’s effects in the brain
Traditionally used as a supplement to improve physical performance, creatine’s broader physiological effects are increasingly being studied. One particular area of research focus is creatine’s effects on the brain. Accumulating evidence suggests that creatine shows promise for attenuating symptoms of concussion, mild traumatic brain injury and depression.
Supplementing creatine monohydrate may increase brain creatine content. Individuals with creatine-deficient syndromes and fewer brain creatine stores show mental and developmental disorders whose symptoms can be partly reversed by creatine supplementation.
Previous studies have yielded mixed results regarding the supplement’s benefits for cognition and memory, and only a few have evaluated creatine’s effects on sleep deprivation. However, a one-week creatine loading regimen has been reported to improve subjective sleep quality and enhance cognitive performance in active men.
The current researchers previously demonstrated that a high single dose of 0.35 g/kg creatine attenuated cognitive impairment during sleep deprivation. The cellular stress resulting from a lack of sleep appeared to create conditions for increased intracellular uptake when supplemented with a higher dose.
Under normal physiological conditions, without cellular stress, creatine may require a week of supplementation to produce noticeable cognitive effects due to its low central nervous system absorption. So a “cellular stress state appears to be a decisive condition for an increased uptake”, the researchers noted.
They wanted to establish whether the cellular stress state alone drives increased creatine uptake, or whether the high extracellular availability of creatine provided by the supplement is also relevant.
“Our results indicate that a beneficial effect is still present at the lower dose, although less pronounced, suggesting that both factors—the cellular stress state and sufficient extracellular creatine availability—are essential for the observed response,” they wrote, noting that the results should be interpreted with caution due to the absence of metabolic brain measurements and statistical comparisons.
Study details
Twenty-nine healthy subjects, without sleep disorders, were randomly assigned a single dose of 0.2 g/kg creatine monohydrate or placebo in a crossover design. During a total of 21 hours of sleep deprivation, they performed cognitive performance tests at the start of the study period and at 3, 5.5 and 7.5 h post-intervention.
“Our results show that a dose of 0.2 g/kg creatine is associated with a reduced deterioration in cognitive performance during sleep deprivation,” the researchers wrote. “Although the effect is less pronounced than with a high dose of 0.35 g/kg, there is still an improvement of up to 12%,” they added, noting that the effects are dose-dependent.
The findings also revealed that, compared to males, female participants benefited more on tasks related to logic and language and on the Psychomotor Vigilance Test (PVT). Vegetarians also showed improvements in processing speed, which the researchers attributed to a higher creatine demand, which may be present in females due to brain chemistry and metabolic energy consumption.
The researchers recommended future studies with modifications to increase cellular uptake and further research into specific dosages for different populations.
Source: Nutrients; doi: 10.3390/nu18081192; “Single-Dose Creatine Reduces Sleep Deprivation-Induced Deterioration in Cognitive Performance.” Authors: A. Gordji-Nejad et al.
