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Exercise-Induced Microscopic Hematuria Developed 12 Hours After Powerlifting
C. Thorsten
March 2007
Abstract: Athletic pseudonephritis was studied in an apparently-healthy test subject after a workout with maximal to maximum poundages in the squat, bench press, and deadlift exercises. Urine sediments exhibited microscopic changes that became evident approximately 12 hours post-workout. The presence of hemoglobin and / or degraded erythrocyte residues was noted only in the specimens collected c. 12 hours after exercise. Compaction of these residues into casts seemed dependent on whether the subject had slept or stayed active before specimen collection.
Introduction: Much of the past work on sports-induced hematuria has revolved around marathon runners and boxers (see for example Siegel et al., 1979), with apparently little attention to weightlifting and powerlifting. The latter is an extremely strenuous anaerobic activity carried on using nearly the heaviest weights that the athlete is capable of moving. Powerlifting introduces enormous short-term physical strains and muscular demands; advanced strength athletes routinely handle weights well in excess of bodyweight. Heavy squats and deadlifts in particular have a reputation among lifters for increasing testosterone secretion; this in itself presents an interesting area of study with regard to biochemical and physiological changes in various organs, including the kidneys.
It is by now well-known that exercise can induce temporary, generally
harmless nephrologic changes that mimic serious kidney disease. While
actual renal failure is possible during or after most any sort of strenuous exercise, it
normally requires aggravating factors such as dehydration or chronic use
of non-steroidal anti-inflammatory drugs (NSAIDS).
The present case study employed test subject who was apparently healthy
in all major respects and engaged in minimal to zero use of NSAIDS and
antibiotics. There was no hypertension, diabetes, or other notable
condition; there was no smoking and no use of any other medication
or drug. Abundant hydration was ensured during all exercise sessions.Materials used:
Droppers & Pasteur pipettes
Urine Reagent Strips (9-parameter)
Compound Microscope (Observer III)
Slides, glass
Coverslips, glass
Centrifuge, Ultra 8V
Mini-VID eyepiece camera
Methods & Observations:
The microscope was an Observer III, having a maximum of 400x magnification.
The eyepiece camera was a Mini-VID USB.
Test subject was a male volunteer, age 30-35. Body weight was
200 lbs (91 kg). There was no evidence of underlying renal pathology
or other afflictions.
The volunteer reported eating mostly balanced meals, with general avoidance
of alcoholic beverages, carbonated soft drinks, and deep-fried foods.
Regular diet included a multi-vitamin supplement taken once per day.
Other dietary factors noted were (1.) regular post-workout consumption
of extra protein, and (2.) overall caloric intake of ca. 3000 calories per day, including
anywhere from 90-150 grams daily protein in total. Neither of these
habits was deemed at all unusual for a weightlifter.
In order to limit variability, the only solid meals consumed on the
day of each test trial consisted of rice and lentils; all other food
intake consisted of a protein drink containing 25 g. of pure whey protein
(NutraBio.com Inc., PO Box 626, Middlesex, NJ) in 8 oz. of water.
The whey protein was chosen for its lack of additives of any kind (e.g., added glutamate, artificial
sweeteners, etc).
Two trials were conducted over the course of two weeks; see "experimental
schedule", below.Exercise routine:
Weight-lifting for the experiment consisted of approximately 45 minutes
of heavy, low-repetition barbell squats, deadlifts and bench presses.
Poundages were such that only 1 to 3 repetitions were possible per set.
Two sets of this type were done for each exercise, with the 2-3 warm-up
sets in each case having been done at ca.
70% or less of maximum poundage. In keeping with the test subject's
typical weightlifting pattern, at least one sub-maximal, low- to mid-repetition
set was also done after the maximal / maximum ones. In both trials
the subject did the workout in the evening, as was his normal habit;
exercise commenced at about 8:30 PM.
Subject was allowed to consume 30 g of whey protein (suspended in pasteurized,
low-fat milk) and one tablet of a C & B-vitamin supplement, as was
his normal post-workout habit.
A second whey protein "shake" was consumed 2 to 2.5 hours after the
workout, which was also the lifter's normal, post-exercise habit.Experimental schedule:
In this test athlete the microscopic hematuria was delayed in its onset
and could be narrowed exclusively to the specimen obtained 12 hours post-workout
(margin of +/- 30 minutes). However, all instances of renal clearance
were collected and examined as they became available. Samples collected
before or after the 12-hour specimen showed virtually no microscopic hematuria
or other formed elements; although all samples were kept, they had
little of interest relative to the 12-hour sample. 
It is important to reiterate here that even samples collected as little
as one hour before or after the 12-hour specimen showed virtually no elements
of interest.
The experiment was done twice over the course of two weeks:Trial 1: The subject went to sleep about 3 hours after the workout. A first-morning specimen was collected 12 hours post-workout (the "resting" 12-hour sample). Samples from before going to sleep were kept and refrigerated at 4-8ºC. Subject was to collect any samples voided prior to collection of the 12-hour sample; there was one such sample, kept at 4-8 ºC until it could be examined
Trial 2: The subject stayed awake all night and went through a normal waking routine (walking, sitting, standing- but no strenuous exercise) for the whole time after the workout. A specimen was collected 11 hours 45 minutes post-workout (the "waking" 12-hour sample). Several other specimens were collected before and after this time.
Sample collection & preparation:
A freshly-voided sample was collected in a centrifuge tube and promptly
studied, with a new one collected at each timed interval. Visual examination
and reagent strip assays were performed before centrifugation.
Samples were centrifuged at ca.
2500 rpm for 10 minutes in the Ultra 8V. In each case the supernatant
liquid was pipetted mostly away, leaving 0.5 mL of liquid in which the
sediments were resuspended.
Timing of sample collection was based on actual renal clearance rather
than a uniform interval.Visual examination:
In both trials, only the "12-hour" specimen showed any noteworthy characteristics. These specimens became extremely cloudy when chilled; centrifugation in both cases yielded an opaque pellet with macroscopically evident blood. It is important to note that blood was not visually evident before centrifugation (i.e., no gross hematuria).
These properties were consistent with a test run that was conducted
several weeks prior on the same subject.Multi-reagent strip tests:
All tests appeared normal / negative, with only "slight trace" or no protein being detectable at any time, despite the fact that the "12-hour" samples became extremely cloudy when chilled. pH was consistently in the 6.0-7.0 range throughout the tests. Specific gravity was 1.020-1.030.
Though there were visual traces of blood and/or hemoglobin pigment
in the sediments of both 12-hour samples, the samples hadn't shown any
such visible traces before centrifuging. They evidently didn't present
enough blood for the reagent strips to detect. Sediment Microscopy:
No stain was used in most cases, since most of the formed elements
of interest were visible without any added colorant.
Specimens collected before and after the 12-hour samples were inspected
just to be certain they contained no casts or other important formed elements;
this was verified and the specimens put aside.
In all cases, the usual calcium oxalate (weddelite) crystals formed
upon standing, especially at lower temperatures as would be expected.
There was also some uric acid, amorphous phosphate, and other, typical crystals.
| Figure 1. Typical microscopic appearance
of all centrifuged samples (except for the 12-hour); in other words,
there were virtually no formed elements of interest. Magnification: 100x. |
|
| Figure 2. Casts of any kind were
extremely scarce in most centrifuged samples (except the 12-hour).
Shown here: an isolated hyaline cast from a 3.5-hour
post-workout centrifuged sample. This was the only cast or cast-like
element noted in any of the non-12-hour samples. Magnification 100 x. |
|
| Figure 3. The "resting" 12-hour
sample, obtained from Trial 1 of the experiment. Note the
dense, brownish cast composed of hemoglobin / degraded RBCs. There
were many such casts in the sample. Figure 3a: Another view of the 12-hour sample from Trial 1. Some of these casts served as nucleation points for calcium oxalate crystals that later formed in vitro. The RBC casts, not the crystals, were the important elements. Magnification: 100 x. |
|
| Figure 4. The "waking" 12-hour
sample, obtained in Trial 2 of the experiment. Casts, when
evident, were very diffuse ("pre-casts"), but there was significant hemoglobin
/ degraded RBC debris. Magnification 100 x. |
|
Discussion:
A relatively short period of powerlifting-- a maximally-strenuous,
anaerobic exercise-- caused significant but temporary nephrologic changes
in a healthy test subject. These transient changes appeared almost
exclusively in those specimens collected approximately 12 hours post-workout.
Their predominant microscopic feature was abundant hemoglobin residue and/or
heavily-degraded erythrocytes.
All other specimens pre- and post-workout were studied carefully under
the microscope but showed virtually no transformation, with the possible
exception of increased crystal formation. One sample contained crystalloid
masses of what appeared to be ammonium biurate, but their identity was
not confirmed. There was not enough crystal formation to deem noteworthy,
however.
The 12-hour samples indicated a fairly sudden but temporary leakage
of blood into the renal filtrates. It is commonly-known that strenuous
exercise can increase glomerular permeability, allowing macromolecules
and erythrocytes to pass into renal filtrates. In the present experiment,
the concentration of hemoglobin and/or degraded erythrocytes in the 12-hour
samples suggested a definite but delayed increase in glomerular permeability.
Although the turbidity observed in the chilled 12-hour samples was most
likely protein, the urine reagent strips did not detect it. While it
may be that the proteins released during the experiment were not the ones
for which the test was designed, it seems even more likely that there was
interference. The test strips will detect albumins but not globulins,
even though both were probably present in the sample. It is important
to realize here that, if the relatively gigantic red blood cells were able
to pass the glomeruli en masse, the globulins would easily have passed
as well. We might even expect the contents of the urine here to have
reflected the relative composition of blood plasma proteins; this composition,
in turn, may have been special for a subject who powerlifted and consumed
large amounts of dietary protein. In any case, a more generalized lab
method for protein could have yielded better results here. The use
to which the strips were put in this experiment was not quite the intended
one; however, it did give some rough figures to suggest there were
no glaring abnormalities (e.g., glucosuria, aciduria / alkalinuria)
in the test subject.
In the weightlifting world, heavy squats and deadlifts are virtually
synonymous with testosterone and a resultant increase in body muscle mass.
One may recall the story of Peary Rader, who transformed himself from
the proverbial "100-pound weakling" (in his case, 128 lbs) into a 210-lb
athlete possessing fearsome strength (Strossen, 1992). While such
outward physiologic changes are easily measured, heavy exercise also sets
off a complex cascade of biochemical activity that by all accounts is still
poorly-understood.
There have been multiple theories for the actual cause of exercise-induced
hematuria and proteinuria. Gambrell and Blount (1996) discuss traumatic
and non-traumatic origins, with the former thought to arise from either direct
impact due to contact sports or from "shaking and jostling" associated with
aerobic sports (1996). The so-called "big three" exercises of powerlifting,
however, seem to involve neither shaking nor impact to the region of the
body containing the kidneys, unless one posits some mechanism whereby tightening
lower back muscles exert pressure on the kidneys.
Recent studies have suggested the role of nitric oxide (NO) in glomerular
permeability changes (Gündüz et al., 2003). Whether NO plays
a role or not, there is still no clear, overall mechanism established (Senturk
et al., 2006).
Increased permeability may depend on multiple factors; at least
one study suggests involvement of catecholamines (Poortmans et al., 2001). Clonidine, a
catecholamine suppressant, was shown to reduce renal clearance of albumin
by as much as 40% (2001).
Whatever the actual mechanism, the excretion of products that pass
the glomerular membrane is undoubtedly affected also by other, less-hidden
factors (e.g., amount of water ingested). While the present experiment
has suggested a difference between the sleeping and waking states on the
morphology of urine sediments, this may depend partly on the fact that a
sleeping test subject doesn't consume water or food. Decreased water
consumption inevitably leads to a more concentrated renal filtrate, which
could explain the compactness of casts observed in the "sleeping" trial.
Subsequent experiments can clear this up if the "waking" subject(s) stop
drinking water or eating food for the 8 hours leading up to collection
of the "12-hour" specimen. It remains noteworthy, however, that in
both trials the maximum clearance of RBCs and / or hemoglobin through the
kidneys happened at the same time relative to the strenuous exercise, regardless
of the differences in food intake, water intake, sleep, movement, and other
factors that existed between the two. This suggests an intrinsic physiological
and/or biochemical mechanism that is responsible for the time delay.References:
Gambrell, R. C., and Blount, B. W. "Exercise-Induced Hematuria". Am. Fam. Phys. 53(3):905-911 (1996 Feb. 15)
Gündüz, F., Kuru, O., and Senturk, U. “Effect of Nitric Oxide on Exercise-Induced Proteinuria in Rats”. Journal of Applied Physiology 95: 1867-1872 (2003).
Poortmans, J.R. , Haggenmacher, C., and Vanderstraeten, J. “Postexercise Proteinuria in Humans and its Adrenergic Component.” J. Sport Med. Phys. Fitness 41(1): 95-100 (2001 March)
Senturk, U., Kuru, O., Kocer, G., and Gunduz, F. "Biphasic Pattern of Exercise-Induced Proteinuria in Sedentary and Trained Men". Nephron Physiology 105(2): 22-32 (2006 Dec. 14).
Siegel, A.J., Hennekens, C.H., Solomon, H.S., et al. "Exercise-related Hematuria. Findings in a Group of Marathon Runners. JAMA. 241: 391-392 (1979).
Strossen, Randall. "Peary Rader (1909-1991)", Hardgainer, March 1992.
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