Astaxanthin Reduces Exercising Heart Rate by 7% in Overweight Individuals.

METHODS

Experimental Design

The current study implemented a double-blind, between-subject study design with dependent variables examined at multiple timepoints across each trial. To best observe changes in our selected dependent variables, subjects reported to the laboratory on two separate occasions (i.e. pre-post) following 4 weeks of astaxanthin supplementation.

Subject Approval from the Institutional Review Board was granted before recruiting subjects (University of North Alabama, Institutional Review Board #: 20-21-071). Each subject completed a Physical Activity Readiness Questionnaire, a medical questionnaire, and provided their written and verbal consent to voluntarily participate in the present study. Inclusion criteria for each subject included the following: 1) between the ages of 18-45; 2) free of any cardiometabolic disease medication; 3) classified as overweight with a bodyfat percent of ≥ 20% for males and ≥ 25% for females; 4) and not currently pregnant or actively trying to become pregnant. Additionally, subjects eliminated all dietary supplements at least two weeks prior to the start of the study. Using G-Power software and changes to bodyfat as a primary dependent variable, we determined a priori that 20 subjects would be sufficient to achieve a desired power of 0.85, using a moderate-high effect size, and an alpha level set at 0.05. Although 46 individuals were recruited, only 21 fit the inclusion criteria and were randomized into either an astaxanthin or placebo group following their first visit. Due to two participants withdrawing from the study as a result of health concerns not related to the study procedures, 19 subjects were included in statistical analysis.

Preliminary Data During the first visit, subjects had their body composition assessed via bioelectrical impedance analysis as well as height, mass, and blood pressure by the same, trained investigator pre-post intervention. Following the collection of anthropometric data, subjects who met inclusion and exclusion criteria were then asked to attempt to maintain their current dietary habits for the duration of the intervention. Dietary intake was then recorded pre-post intervention via 3-day food logs which consisted of 2 weekdays and 1 weekend day (i.e. Thursday, Friday, Saturday) to better reflect typical intakes. Subjects met with the primary investigator and were instructed how to complete the food logs, regarding quantity size and liquid amount estimations. Total energy intake, carbohydrate, protein, and fats were analyzed for nutrient amounts using MyFitnessPal and were then used in statistical analysis.