The effects of IQPLUS Focus on cognitive function, mood and endocrine response before and following acute exercise

Journal Title (Medline/Pubmed accepted abbreviation): J Int Soc Sports Nutr
Year: 2011
Volume: 8
Page Numbers:16 (open access)

Summary of background and research design:

Background:Phosphatidylserine (PS) is a naturally occurring phospholipid in plant and animal cell membranes that serves many regulatory and signaling functions. A typical Western diet includes ~130 mg/day of PS. Endocrine and cognitive functions may be affected by PS levels, and supplementation may further improve these functions. Clinical evidence has shown short-term high-dose PS supplementation (600 mg/d) attenuates cortisol response to exercise, and long-term, low-dose supplementation (200 mg/d) reduced perceived stress and improved golf performance; PS supplementation from 200 to 800 mg has demonstrated improvements in mood, cognitive function, sports performance, endocrine stress response, and soreness after exercise.  

Hypothesis/Purpose: The purpose of this study was to evaluate the effects of PS supplementation on cognitive function, mood, and endocrine stress response following intense resistance exercise.

Subjects: Eighteen physically active (lower body resistance exercise ≥ 1/wk for past 3 mo) men (mean age, 22.5 ± 2.2 yr; height, 1.77 ± 0.06 m; weight, 84.4 ± 13.6 kg) participated in the study.

Experimental design: Randomized, double-blind, cross-over 

Treatments and protocol:
Each man was randomized to 2 servings/day of either PS (enriched soybean-derived phospholipids; 200 mg PS) or placebo (rice flour) for 14 days before lower body resistance testing. Each man completed both conditions followed by an identical exercise session without a washout period between conditions. Lower body resistance testing consisted of a warm-up (treadmill, brisk walk for 5 min) followed by 5 sets of 10 repetitions at 70% of 1-repetition maximum (1-RM; determined previously) squats, leg press, and leg extension, with a 90-second rest between sets and a 180-second rest between exercise types. Cognitive function and mood were assessed by a serial subtraction test and a Profile of Mood States questionnaire, respectively, before supplementation and exercise and at 5 and 60 minutes after exercise. Blood samples were collected for cortisol and testosterone levels before supplementation and exercise and at 5, 15, 25, 40, and 60 minutes after exercise.

Summary of research findings:
  • Cognitive function was improved from pre-exercise to 60 minutes after exercise under both conditions (speed of correct calculations, P = .02).
  • In the PS supplementation group, cognitive function was improved before exercise compared with the placebo group.
    • Pre-exercise: significantly increased speed of calculation by 20% (P = .001); decreased number of mistakes by 39% (P = .53); increased number of correct calculations by 13% (P = .07)
    • 60 minutes after exercise: increased speed of correct calculations by 20% (P = .007)
  • Overall, there were no differences between conditions or a treatment × time interaction for mood.
    • Subsections did have a main effect for time:
      • Decrease in vigor from pre- to 5 minutes post-exercise (P = .005) and 60 minutes post-exercise (P = .000)
      • Increase in fatigue from pre- to 5 minutes post-exercise (P = .014)
      • Increase in tension from pre- to 5 minutes post-exercise (P = .049); decrease in tension from 5 minutes post-exercise to 60 minutes post-exercise (P = .031)
  • Overall, there were no differences between conditions or a treatment × time interaction for cortisol and total testosterone levels, or for testosterone to cortisol ratio.
    • There was a main effect for time, increasing both cortisol and testosterone levels from pre-exercise levels in both conditions (P < .001 and P = .004, respectively).
      • Cortisol levels significantly increased at 5, 15, and 25 minutes post-exercise and significantly decreased from all previous post-exercise time points at both 40 and 60 minutes post-exercise (P < .04).
      • Testosterone levels significantly increased at 5 and 15 minutes post-exercise and significantly decreased from both previous post-exercise time points at 60 minutes post-exercise (P < .04).

Interpretation of findings/Key practice applications:

Supplementation with PS in this study significantly improved cognitive function before intensive resistance training. However, exercise performance was not assessed and, therefore, no relationship between cognitive function and exercise performance can be made. Previous research has suggested that the improvement in cognitive function included a more relaxed state of mind that could improve performance in sports requiring this mind-set. Mood and endocrine changes were not different with PS supplementation, but that could be due to many variables such as dose and duration of supplementation, differences in training status (physical and mental stress), and untrained versus trained individuals. Further study is needed to elucidate the optimal PS dosing regimen and populations who would receive benefit from PS supplementation.


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