The Acute Effects of Capsiate During Exercise

Hypotheses

Based on the rationale and brief background above we propose the following substantive hypotheses:

1. Ingestion of capsiate 30min prior to exercise will elevate resting and exercising oxygen consumption (VO2) in a hierarchical manner: 10>3>0mg
2. Respiratory exchange ratio will be shifted toward greater lipid oxidation (i.e., toward 0.7) in a hierarchical manner: 10>3>0mg

Our secondary hypotheses are:

• A greater rise in glycerol and FFA at rest and during exercise in a hierarchical manner: 10>3>0mg
• A greater rise in catecholamine (Epinephrine and Norepinephrine) concentrations in a hierarchical manner: 10>3>0mg

Protocol We will use a double-blind repeated measures study design in which subjects will complete 3 trials - 0, 3, and 10mg - of capsiate. Based on acute effects seen in previous studies 1, 4 we anticipate that a sample size of 12 subjects (all subjects will be males to control for possible sex-based differences in substrate oxidation during exercise) would appear to be adequate to see significant effects of capsiate on oxygen consumption and substrate oxidation. Randomization will be done on a counterbalanced and blocked basis with 3 conditions and 6 possible order combinations and with 12 subjects, each subject will be randomized in a counterbalanced manner so that 2 subjects complete each trial order.: ABC, ACB, BCA, BAC, CAB, CBA, order of treatment and assignment will be performed at random and under complete control of the McMaster University Pharmacy. The chief pharmacist - Dr. Gita Sobhi - will give the code for each treatment to the PI only after completion of the data analysis. We will use a cycling protocol at an intensity of 55% of each subject's individual peak VO2 for 90 minutes. Workload to determine 55% of peak VO2 will be according to the algorithm detailed by Latin et al. 17 This exercise intensity is adequate to elevate lipolysis (i.e., glycerol and FFA), catecholamines, and show a substantial shift in RER toward lipid oxidation with increasing exercise duration. The PI has experience with this protocol and has measured substrate oxidation previously using the same or very similar protocols. 18-20 Moreover, this type of exercise intensity represents an intensity that elicits an exercising RER in or around 0.9 and thus where there is a good blend (65:35 carbohydrate:lipid) of fuels being oxidized, but is also an intensity close to what has been referred to as 'fatmax', which is defined as the intensity of exercise at which the maximal rate of lipid oxidation occurs. 16, 21-23 Thus, in terms of selecting an exercise intensity that will reveal the impact of capsiate on both energy expenditure and substrate oxidation we believe that this intensity is an optimal one. We will collect breath (breath-by-breath and ensemble averaged into 30s bins) and blood samples for 30min into recovery to assess to what degree excess post-exercise oxygen consumption is elevated and whether this is accompanied by significant fat oxidation and elevated plasma catecholamines.

We will use recreationally active subjects (peak VO2 > 40 ml/kg/min) so that we're assured they will be able to complete the protocol. Subjects will be screened using a standard health questionnaire (see attached consent form) and a maximal exercise test. Subjects will be healthy non-smokers between the ages of 18-30 and will be recruited from the local McMaster University campus or surrounding community. Exercise trials will take place in the overnight fasted state (last meal at 2000h) after having consumed a standardized diet on the day prior to the exercise trial. Having subjects in the fasted state does not present a risk or barrier to the subjects completing the trial as based on past experience with this protocol. It is emphasized that being in the fasted state is also the easiest state in which to interpret the data from the standpoint of substrate oxidation. The pre-trial day diet will consist of energy estimated for each subject based on the Harris-Benedict equation 24 with an activity factor of 40%. The diet will be 50:30:20 in terms of percent energy from carbohydrate:fat:protein. Subjects will consume the same diet on the days prior to each exercise trial to control for pre-study calorie and carbohydrate/fat intake, which could affect substrate oxidation. Subjects will refrain from consumption of alcohol and caffeine on the day of the trial. Trials will take place at least 5d (but no more than 7d) apart and will commence at a time between ~7-10am and will proceed according to the schematic timeline shown in figure 1. The testing time for subjects will remain consistent throughout the study. We also believe that it is prudent for subjects to consume a fixed and constant volume of water (1000ml) during all trials to prevent dehydration and to allow subjects to complete the ride in safe manner.

All data will be analyzed using a repeated measures two-way analysis of variance with time as a within factor and dose as a between factor. Significant ANOVA effects will be further scrutinized using Tukey's test as a post-hoc procedure. Where significant correlation of one variable with another exists an analysis of covariance may also be performed. Significance will be accepted at P<0.05.

Analysis VO2 and RER for energy expenditure and substrate use - standard equations using revised non-protein RER as described by Jeukendrup and Wallis. 26 HR - using Polar™ monitoring and on-line collection via the AEI metabolic cart BP - using Finapres™ blood pressure monitoring. Blood glucose, glycerol, lactate - fluorometric methods as detailed in Passoneau and Lowry 27 and as performed previously by the PI. 18, 20, 28 Free fatty acids - colorimetric micro-assay method from WAKO diagnostics (http://www.wakodiagnostics.com/r_nefa.html) Catecholamines - using reverse phase HPLC and electrochemical detection as described previously. 18, 20