Senior Honors Projects, 2010-current

Preferred Name - First Author

Parker, Jordan

Date of Award

Spring 2016

Document Type

Dissertation/Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Kinesiology

Advisor(s)

Nick Luden

Abstract

Purpose: Brain Derived Neurotrophic Factor (BDNF) is part of the superfamily of neurotrophins including: nerve growth factor (NGF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4). Recent evidence suggests that aerobic activity can increase BDNF levels both during and following exercise. Likewise, dietary habits have been shown to alter BDNF levels. However, nothing is known about the effect of BDNF levels during aerobic activity under specific dietary interventions. The purpose of this study was to examine the effects of specific macronutrient supplementation on BDNF levels during aerobic exercise. Methods: We had the opportunity to determine BDNF levels in blood samples obtained from two separate projects whereby subjects completed 2 hours of cycling. Specifically, 14 endurance-trained cyclists (VO2 max : 62 ± 7 ml/kg/min) from two previous studies: Study A focused on protein (PRO) and placebo (PLA) supplementation (6 subjects: 3 males and 3 females) and Study B focused on carbohydrate (CHO) supplementation (8 subjects: 6 males and 2 females) during constant load cycling. Both studies had nearly identical exercise protocols of constant load cycling for 120 minutes at 50% (CHO) and 55% (PLA/PRO) of peak power at VO2 max. In both studies blood samples were obtained prior to exercise and immediately following the 120-minute ride, allowing us to make preliminary comparisons between studies. Upon the start and every 15 minutes during steady state cycling, subjects were given a PLA, PRO, or CHO drink. Serum BDNF concentration both before and after the two-hour fixed intensity trial were analyzed with standard ELISA (enzyme-linked immunosorbent assay) methodology. The following comparisons were made: PRO vs. PLA (Study A) and CHO (Study B) vs. PLA (Study A). Results: BDNF levels ‘almost certainly’ increased (24 ± 10%) following 120 minutes of cycling with PLA. Similarly, BDNF levels were ‘very likely’ elevated (32 ± 32%) following 120 minutes of cycling with PRO. All 6 subjects experienced an increase in BDNF levels under the PLA condition, while 4 out of 6 subjects increased BDNF levels with PRO. Conversely, the change in BDNF levels was ‘unclear’ (2 ± 17%) following 120 minutes of cycling with CHO. There was an ‘unclear’ difference between the PLA vs. PRO trials, while the PLA vs. CHO trials conveyed a ‘likely’ difference in post-exercise BDNF response. Conclusion: BDNF levels were elevated in PLA and PRO treatments, while the CHO treatment had unclear effects. PLA data confirms elevated BDNF response due to aerobic exercise, while PRO data suggests a similar response. BDNF response seemed to be blunted by CHO treatment. The results from this project justify follow-up investigations to determine the precise relationship between CHO supplementation and the BDNF response to aerobic exercise.

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