Download Ammonia Perspiration During Exercise

Ammonia Perspiration during Exercise
Michael Dobson
Biology 493
Advisor: Dr. Day
ABSTRACT
Ammonia excretion was measured on eight male
volunteers to determine the role of perspiration on ammonia
clearance during maximal exercise. Sweat and blood samples
were taken pre- and post exercise. The samples were analyzed for
ammonia concentration. There was a significant (p< 0.05)
increase in both blood and sweat as a result of the exercise bout.
The increase in the concentration of ammonia in sweat suggests
the sweat must play a role in ammonia clearance following
exercise.
INTRODUCTION
Ammonia is produced as a byproduct of muscle activity. As exercise intensity or
exercise duration increases ammonia production rate also increases (Graham et al. 1995).
During high intensity exercise ammonia production comes from the purine nucleotide cycle
(PNC) this cycle typically occurs in the fast-twitch fibers (MacLean et al. 1991). In prolonged
sub-maximal exercise ammonia production comes from the breakdown of branched chain amino
acids. The production site for ammonia during branch chain amino acid metabolism is generally
in the slow-twitch fibers (Graham et al. 1995). Not much is known about the pathway of
ammonia from blood to the sweat glands. Czarnowski and Gorski (1991) theorize that the
ammonia in perspiration is due to diffusion from high pH in the blood to a lower pH in the sweat
glands.
Yuan and Chan (2000) found that after fifteen seconds of intense sprinting exercise
ammonia production is at its peak. Also, during their study higher blood ammonia levels were
collected when exercised on the bicycle ergometer than from a treadmill. They theorize that this
was due to a larger recruitment of the fast-twitch fibers in relation to running on a treadmill.
Ammonia is postulated to play a role in muscle fatigue. Muscular fatigue is commonly defined
as a failure to maintain the required or expected force or power output (Fushimi et al. 2001).
The causes of muscular fatigue involve specific impairments within the muscle itself, including
transmission of the neural stimulus to the muscle at the motor end plate and propagation of that
stimulus throughout the muscle. Other events that result in muscle fatigue include disruption of
calcium release and uptake within the sarcoplasmic reticulum, substrate depletion and various
other metabolic events that impair energy provision and muscle contraction. Fatigue can also
result from alterations within the central nervous system (CNS). Although essentially nothing is
known about the specific mechanisms underlying this type of fatigue, ammonia build-up in the
CNS could lead to altered function, which would impair motor function, lethargy, convulsions,
ataxia and even coma (Davis 1995).
Peripheral fatigue may also play a role in muscle fatigue. This occurs at the level of the
sarcomere and involves failure at the neuromuscular junction, sarcolemma and transverse
tubules. Muscle fatigue desensitizes muscle spindle threshold, thereby decreasing afferent feedback to the CNS (Meyers et al. 1999).
At rest, the liver removes ammonia as urea (Wagenmakers 1998). During exercise,
blood is shunted from the liver and kidneys to supply muscles with more oxygen. This means
that the liver is removing little or no ammonia. Some of the ammonia is released into the blood
and another portion is retained in the muscle then released into the blood during recovery.
Ammonia is also utilized in the formation of alanine and glutamine within the muscle
(Czarnowski and Gorski 1991). In the branch chain amino acid cycle an amine group is
removed and a carbon skeleton is left. The carbon skeleton is oxidized to make glucose through
gluconeogenesis or converted into fat for storage. The amine group picks up another hydronium
ion and leaves as ammonia (Houston 1995).
Possible clearance routes for ammonia in the blood are sweat and expiration (Graham et
al. 1995). As blood ammonia increases the equilibrium concentrations are changed and the need
for ammonia to be cleared increases. Ammonia then diffuses from the plasma to the sweat
glands where it is excreted (Czarnowski and Gorski 1991).
The purpose of this study was to measure the concentration of ammonia secreted through
sweat glands and compare that to a resting sweat ammonia concentration.
METHODS
Eight male volunteers were asked to participate in this study. Their ages ranged from 22
to 26 years. None of the volunteers had a scheduled workout routine but all were active.
Before exercise the volunteers were placed in a sauna for approximately 15 minutes
sweat was collected from the forehead using a micropipette tip by capillary action. Before the
sweat sample was taken a brief cleansing was performed using 70 percent isopropyl alcohol. A
sample of approximately five milliliters was obtained. Ammonia levels were obtained by way of
a blood chemistry analyzer.
A resting blood ammonia level was taken from the volunteers at rest. Blood was
obtained by way of a finger prick. Blood ammonia was analyzed in the same manner as the
sweat.
A ramped pedal exercise was conducted on a bicycle ergometer. The exercise consisted
of increasing resistance at thirty second intervals until exhaustion. This was conducted at room
temperature. Blood and sweat samples were then taken immediately post exercise in the same
manner as outlined previously.
Each person’s samples were compared, pre- to post, using paired T- tests. All samples
together were compared using means and standard deviations.
RESULTS
The mean pre-exercise blood ammonia concentration was 73 (+14 SD) µL/dL (Table 1).
The mean post exercise blood ammonia concentration was 224 (+26 SD) µL/dL (Table 1).
Using these means a paired T-test was used to compare ammonia concentration before and after
exercise. There was a statistically significant (p< .05) increase in plasma ammonia due to the
exercise (Table 1).
Table 1. The ammonia concentrations in blood pre- and post exercise.
Volunteer
Blood (µL/dL) Pre- exercise
Blood (µL/dL) Post exercise
1
59
191
2
66
226
3
87
248
4
88
254
5
67
210
6
93
241
7
55
183
8
72
236
Mean
73
224
Standard Deviation
+ 14
+ 26
T- value
-28.71
P- value
.000
The mean pre-exercise sweat ammonia concentration was 4878 (+1129 SD) µL/dL
(Table 2). The mean post exercise sweat ammonia concentration was 6692 (+1155 SD) µL/dL
(Table 2). These means were compared using a paired T-test. The results of the statistical test
showed a significant (p< .05) increase in ammonia from sweat sampled after exercise (Table 2).
Table 2. The ammonia concentrations in sweat pre- and post exercise.
Volunteer
Sweat (µL/dL) Pre-exercise
Sweat (µL/dL) Post exercise
1
4780
6827
2
5932
5540
3
2942
7734
4
4128
8706
5
5412
6213
6
6230
7214
7
5624
5342
8
3974
5963
Mean
4878
6692
Standard Deviation
+ 1129
+ 1155
T- value
5.53
P- value
.001
DISCUSSION
The results found a significance (p< .05) in the increase of ammonia from the resting
sweat and blood to the exercise sweat and blood. This finding supports the postulate of
Czarnowski and Gorski (1991) who suggested that ammonia diffused from the plasma to the
sweat glands during exercise, when the blood was shunted from the liver and kidneys. These
results suggest that while the sweat glands are a source of ammonia excretion and that they can
play a major role along with expiration and storage within muscles and blood during exercise
while no urea is being produced.
The concentrations difference found in this study and Czarnowski’s and Gorski‘s may be
due to the differences in exercise routines and/or the method of analyzing the ammonia
concentrations. The exercise routine in this study differs by generating ammonia from the PNC.
Whereas, Czarnowski’s and Gorski’s exercise was extended over a period of 30 minutes. There
study would have utilized the branched chain amino acid cycle of the oxidative metabolism.
Also this paper used a blood chemistry analyzer whereas Czarnowski and Gorski used an
enzymatic reaction to calculate the ammonia concentration.
Further research may want to focus on sweat as a temporary clearance route more closely
and analyze the production of ammonia and compare it to the maximum rate of ammonia
excretion through perspiration and expiration in humans.
ACKNOWLEDGEMENTS
I would like to thank Dr. Day not only for the suggestion of this project but, also the
guidance and overseeing that he provided. I would also like to thank the rest of the biology
faculty that spent time to provide useful corrective information and encouragement. And finally
the volunteers whom without I would not have had any useful data.
CITATIONS
Czarnowski D. and J. Gorski. 1991. Sweat Ammonia Excretion During Submaximal Cycling
Exercise. The American Physiological Society 161: 371-374.
Davis J. M. 1995. Carbohydrates, Branched-Chained Amino Acids and Endurance: The Central
Fatigue Hypothesis. International journal of Sport Nutrition 5: S29-S38.
Fushimi T., K. Tayama., M. Fukaya. and K. Kitakoshi. 2001. Acetic Acid Feeding Enhances
Glycogen Repletion in Liver and Skeletal Muscle of Rats. The Journal of Nurtition 131(7): 19731977.
Graham T., J. Rush. and D. MacLean. 1995. Exercise Metabolism. Human Kinetics Publishers.
Champaign. pp131.
Houston M. E. 1995. Biochemistry Primer for Exercise Science. Human Kinetics Publishers.
Champaign. pp 77.
MacLean D. A., L. L. Spriet, E. Hultman. and T. E. Graham. 1991. Plasma and Muscle Amino
Acid and Ammonia Responses During Prolonged Exercise in Humans. The American
Physiological Society 161: 2095-2103.
Meyers J. B., K. M. Gisloewocz., R. A. Sneider. and W. E. Prentice. 1999. Proprioception and
Neuromuscular Control of the Shoulder After Muscle Fatigue. Journal of Athletic Training
34(4): 362-367.
Yuan Y. and K. Chan. 2000. A Review of the Literature on the Application of Blood Ammonia
Measurement in Sorts. Research Quarterly for Exercise and Sport 71(2): 145-151.
Wagenmakers A. J. M. 1998. Muscle Amino Acid Metabolism at Rest and During Exercise:
Role in Human Physiology and Metabolism. Exercise and Sport Sciences Reviews 26: 287-314.