Are you drinking any replinishing drinks containing sugar or a
stimulant? Eating sugar or simple carbs? With that low a pulse on
waking you are more than likely dehydrated and your blood volume is
low so your heart keeps beating fast to compensate. I found this on a
site. You need to read it before you end up in trouble as I did. For
further research try "hypovolemic shock" and do it while drinking lots
of water!
"I'm a physician who specializes in Critical Care Medicine. I'm well
versed in the question of circulatory shock. I've done clinical
research on shock, participated in some of the sentinel studies on
shock, and teach the subject to residents and medical students. With
all due respect, I've probably seen more cases of medically
significant dehydration and shock than most of the sensei here have
seen white belts.
Dehydration is not shock. Shock is the global failure of cellular
oxidative metabolism. One form of shock is hypovolemic shock in which
the circulating blood volume is low. Dehydration may cause shock but
is hardly synonymous with shock. Other forms of shock may have normal
blood volume but the volume is maldistributed, e.g. anaphylactic
shock. In some cases of shock the blood volume may in fact be
increased but the heart may be unable to circulate the blood and
oxygen to the tissues, e.g. cardiogenic shock. They just aren't the
same thing at all.
Dehydration is the loss of total body water. Hypovolemia is a low
circulating blood volume. Total body water amounts to about 0.6 liters
per Kg body weight. For the prototypical 70kg person that means a
total body water of 42 l. About 2/3 of this is in the cells
(intracellular water) or about 28 l. About 1/3 is outside of the cells
(extracellular water - 14l). About 2/3 of the extracellular water
(9-1/3 l.) is in the space between the cells (interstitial fluid).
About 1/3 (4-2/3 l.) is in the vascular space (intravascular water).
Most of the time when we lose fluid we lose fluid from the
intravascular space. Sweat glands for example take fluid from the
blood and put it on the skin. The kidneys take fluid from the blood
and produce urine. If we vomit or have diarrhea we lose fluid that the
stomach, pancreas, small bowel etc. has put into the gut lumen from
the blood stream. Thus, most of our fluid losses are from the
intravascular space.
If our fluid loss is slow then our body can move fluid, first from the
interstitial space and then more slowly from the intercellular space,
into the intravascular space to maintain the intravascular volume. If
we lose the fluid suddenly then there is no time to accomplish this. A
good rule of thumb is that we can mobilize about 1-2 l. per day
maximum from the interstitial and intercellular spaces into the
intravascular space. If I cause you to get dehydrated slowly (i.e., I
put you in a warm environment and don't give you free access to water
but yet you have some water) You will not have symptoms till you have
lost about 5-10% of your total body water (2.1 l. - 4.2 l.). At that
time if you stand up suddenly your hart rate will go up but your blood
pressure will remain normal. If you lose 10%-15% (4.2 l. - 6.3 l.)
then when you stand up your blood pressure will go down and you may
become lightheaded. If you lose 15-20% (6.3 l. - 8.4 l.) then your
blood pressure will be down even lying down. At that time you would
probably meet diagnostic criteria for hypovolemic shock.
Of course, if I suddenly take fluid out of your intravascular space
and give you no time to mobilize fluid from the other compartments
into the intravascular space you will have symptoms at lower levels of
fluid loss. That is why some people get lightheaded when they stand up
after donating 0.5 l of blood. All that fluid (about 0.25 L. fluid and
0.25 l. of blood cells) came straight out of the vascular space in a
period of a few minutes.
Most of the fluid we lose each day is in the form of urine. Healthy
people with normal hearts, livers and kidneys make at least 0.5 ml of
urine per Kg body weight per hour (0.012 L./Kg/day). We also lose some
fluid each day in stool, in sweat and in our breath. This amounts to
about 0.5 l per day. In hot conditions, when we have a fever, or when
we exercise, this goes up. This is the principle way we become
dehydrated in the dojo. We need to replace this fluid loss. We also
need to replace the sodium and potassium and other minerals which we
lose in sweat (we lose little in the way of minerals in our breath).
When we become hypovolemic several things happen. First our heart
speeds up. It pumps less volume per beat (stroke volume) but beats
more often to compensate for this and maintain cardiac output (the
number of liters of blood pumped per minute). Second the blood levels
of catecholamines (epinephrine, norepinephrine and dopamine) go up.
This causes blood vessels in the critical organs such as heart, brain,
liver and kidneys to dilate and the vessels in the less critical areas
(gut, muscles) to constrict. Changes in the output from our
sympathetic nervous system reinforce this. The net effect is reduced
blood flow to the muscles and gut and more to the brain etc. Thirdly,
receptors that measure our blood pressure, our sodium level, etc. tell
the brain to increase our volume, this kicks in our thirst mechanism.
Fourthly, the atria of our heart, since they are smaller in diameter
reduce their production of ANP, a peptide hormone that stimulates the
kidneys to make urine. Thus the kidneys reduce their secretion of
sodium and urine.
Training without replacing our fluid and electrolyte losses doesn't
condition us. It doesn't make us tougher. It doesn't improve our
endurance. When we get tachycardic and thirsty our body is telling us
something. We need to listen to it.
Robert S. Joseph, RPh, MD, FCCP
Board Certified Internal Medicine and Critical Care Medicine
Clinical Asst. Professor Medicine
Indiana University School of Medicine
Medical Director, Intensive Care Units
Community Hospitals East and North
Community Hospitals of Indianapolis and Anderson
Good Luck, Maluca |
