OVER-THE-COUNTER
SUPPLEMENTS TO IMPROVE
HUMAN PERFORMANCE
Mackenzie Clark
(Steven J. Albrechtsen, Ph.D.)
Human Performance Laboratory
INTRODUCTION
INTRODUCTION
• The purpose of this research project is to
evaluate the benefits to human performance
of over-the-counter supplement: alkalinizing
agents.
• All of these supplements are readily available
at modest costs without age restrictions or
prescriptions in drug stores, grocery stores,
convenience stores and Wal-Marts.
ALKALINIZING AGENTS
• Alkalinizing agents to increase buffering capacity and reduce lactic acidosis
during exercise have been shown to improve human performance in
controlled studies.
• However, these controlled studies used large quantities of alkalinizing
agents which were associated with undesirable, uncomfortable and
embarrassing side-effects that caused researchers to conclude that
alkalinizing agents were not practical for use in sports competition.
• Within the past year there have been anecdotal reports of athletes in
several sports consuming Alka-Seltzer prior to sports competition in an
effort to improve human performance.
• Alka-Seltzer is an alkalinizing agent, but is generally consumed in
quantities much lower than those which previous research showed to
improve human performance during exercise.
• Controlled research is necessary to evaluate the physiological and
psychological benefits of Alka-Seltzer for human performance during
exercise.
METHODS
Mackenzie J. Clark
Jennah L. Hackbarth
Ingrid Stensvaag
(Steven J. Albrechtsen, Ph.D.)
Human Performance Laboratory
PROTOCOL
• Twenty students and athletes at the University of Wisconsin –
Whitewater were invited to participate in this research project.
• Most subjects were members of the men’s and women’s cross
country teams at the University of Wisconsin – Whitewater.
• The safety of exercise was be established through the completion of
the Physical Activity Readiness Questionnaire (PAR-Q) by each
subject.
• Demographic information, including name, contact information,
gender, birthdate, age, height and weight was obtained from each
subject.
• Maximal oxygen consumption, lactate threshold and corresponding
heart rates were determined during a graded exercise test on a
motor-driven treadmill using a computerized metabolic analysis
system.
EXERCISE TRIALS
• All subjects performed two exercise trials, including an
alkalinizing agent trial and a control trial in a randomized
order.
• During each exercise trial oxygen consumption and heart
rate were monitored continuously using a computerized
metabolic analysis system beginning 14 minutes prior to
each exercise trial, during the two minutes of each exercise
trial and continuing 16 minutes following each exercise
trial.
• Each exercise trial consisted of a modified Wingate
Anaerobic Power Cycle Ergometer Test involving two
minutes of exercise on a computerized cycle ergometer.
SUPPLEMENTS
• Forty minutes prior to each exercise trial the
subjects consumed …
• Four tablets of Alka-Seltzer in water
(alkalinizing agent trial, one-half the maximum
dosage for children and adults from 12 to 60
years of age), or
• The equivalent volume of plain water (control
trial).
EXERCISE
• Modified Wingate Anaerobic Cycle Ergometer
Test
• Two minutes of maximal exercise on a
computerized cycle ergometer.
• Load equal to 7.5% of body weight in kilograms.
• Subjects pedal as fast as possible throughout the
two-minutes test.
• Revolutions were measured and translated to
distances to calculate power in five-second
intervals throughout the two-minute test.
PROTOCOL
• Six minutes of rest while seated in a chair.
• Six minutes of warm-up at 600 kpm/min on a cycle
ergometer.
• Two minutes of recovery while seated on the cycle
ergometer.
• Two minutes of maximal exercise on a computerized
cycle ergometer.
• Sixteen minutes of recovery while seated in a chair.
• Oxygen consumption and heart rate was measured
continuously for 32 minutes using a computerized
metabolic analysis system.
Sample of consumed oxygen and heart rate graph during and exercise trial
OXYGEN DEFICIT
• Limitations of the Aerobic System
– May not be immediately available to supply additional energy.
– Maximal energy demand may exceed the maximal capacity.
• Oxygen Deficit at the Start of Exercise
– Consuming adenosine triphosphate that cannot be immediately
replaced by the aerobic system.
– Analogous to deficit spending where we spend money that we do not
have.
• Defined as the time period during exercise in which the level
of oxygen consumption is below that necessary to supply all
the adenosine triphosphate required for the exercise.
– Submaximal Exercise
– Maximal Exercise
OXYGEN COST
• Oxygen Cost of Leg Ergometer Exercise
• ACSM Leg Ergometer Equation
Oxygen Cost (mL/kg/min) =
1.8 [Work Rate (kgm/min)] / Body Mass (kg) + 7.0 mL/kg/min
Oxygen Cost (mL/kg/min) =
11.016 [Work Rate (watts/kg)] + 7.0 mL/kg/min
OXYGEN DEBT
• Defined as the amount of oxygen consumed
during recovery from exercise, above that
ordinarily consumed at rest in the same time
period.
• Alactacid Component
– Rapid Recovery Phase
– Fast Component
• Lactacid Component
– Slow Recovery Phase
– Slow Component
RESULTS
Mackenzie J. Clark
(Steven J. Albrechtsen, Ph.D.)
Human Performance Laboratory
RESULTS
• Twenty-four subjects total.
– Twelve males.
– Twelve females.
• Eighty exercise trials total.
– Two supplements for each subject.
– Two exercise trials for each subject.
• Twenty graded exercise tests.
– One graded exercise test for each subject.
RESULTS
• Power
• Oxygen Consumption
• Heart Rate
POWER
• Peak Power
– Highest power achieved in any five-second segment
during the two-minute test.
• Average Power
– Average power throughout the two-minute test.
• Minimum Power
– Lowest power achieved in any five-second segment
during the two-minute test.
• Power Drop
– Different in power (i.e., decline in power) between
peak power and minimum power.
OXYGEN CONSUMPTION
•
•
•
•
Rest
Warm-Up
Recovery
Exercise
– Required Oxygen
– Oxygen Deficit
• Post Exercise
– Oxygen Debt
– 2 minutes, 4 minutes, 16 minutes
HEART RATE
•
•
•
•
•
Rest
Warm-Up
Recovery
Exercise
Post Exercise
– 2 minutes, 4 minutes, 16 minutes
POWER
watts/kg
Alka-Seltzer
Control
Peak Power
7.91 + 1.36
8.11 + 1.26
Average Power
5.04 + 0.83
5.07 + 0.85
Min. Power
2.85 + 1.10
2.70 + 1.20
Power Drop
5.06 + 1.60
5.41 + 1.29
OXYGEN CONSUMPTION
mL/kg/min
Alka-Seltzer
Control
Rest
5.53 + 0.82
5.25 + 0.96
Warm-Up
24.22 + 3.05
24.00 + 4.31
Recovery
12.92 + 2.09
12.46 + 2.19
Exercise
43.24 + 7.59
41.83 + 10.81
Required
62.55 + 9.14
62.84 + 9.37
O2 Deficit
19.31 + 7.34
21.00 + 10.44
Post (2)
24.37 + 4.23
24.28 + 5.10
O2 Debt (2)
19.04 + 3.88
19.03 + 4.91
Post (4)
18.34 + 3.16
18.03 + 3.75
O2 Debt (4)
13.02 + 2.78
12.78 + 3.58
Post (16)
10.59 + 2.26
10.24 + 2.17
O2 Debt (16)
5.27 + 1.81
5.00 + 2.08
HEART RATE
beats/min
Alka-Seltzer
Control
Rest
62.84 + 9.18
59.14 + 10.78
Warm-Up
117.37 + 16.20
117.40 + 18.66
Recovery
114.79 + 18.23
118.38 + 21.44
Exercise
170.32 + 11.20
168.40 + 18.56
Post (2)
109.89 + 19.69
110.62 + 20.62
Post (4)
91.58 + 14.53
94.52 + 12.37
Post (16)
85.59 + 11.51
87.57 + 9.27
WHAT DOES IT MEAN?
• The results show that Alka-Seltzer failed to
produce a significant change in performance.
• The Alka-seltzer yielded no significant changes in
oxygen consumption, heart rate or power output.
• Alka-seltzer had lower peak power, average
power and power drop than the control group.
• The reason that Alka-seltzer did not produce a
significant change in performance could be that a
higher dosage of Alka-seltzer is needed to
produce a positive result.
QUESTIONS?