Tuesday, August 11, 2009

New Cardio Study


Headed to Houston tomorrow for a new "spaceflight simulation" study, the purpose of which is to examine how the major systems in the body control blood pressure, heart rate, fluid changes, and chemicals in people that are dehydrated to the same degree as astronauts when they return from weightlessness.

Technically, I am already on Day 6 of this one, though I haven't mentioned much about it because the preparatory phase is rather anti-climactic in comparison to the last two.

There is no required stay at the UTMB ward on Galveston island, because there is no need for medical quarantine or a special nutrition regimen. My big assignment for the week? Tablets. Stage One is simply taking Sodium Chloride pills each day, along with a healthy, "everyday" diet.

Sodium Chloride Tablets
Derived from halite crystal, sodium chloride is... common salt. It's been demonized in recent years for it's ability to raise blood pressure. However, chloride and sodium ions are necessary for the survival of all known living creatures... making it a basic dietary mineral.

Salt is involved in regulating fluid balance, as it is one of the primary electrolytes: sodium, potassium, magnesium, and calcium. There’s tons of literature about OVER-consumption, but either too much or too little salt in the diet leads to health issues: electrolyte imbalance, heartburn, kidney problems, and the ones that get the most attention -- hypertension (high BP) and heart enlargement.

Sodium Chloride
Truthfully, I’ve never been terribly cautious about my salt intake, because I’ve always had low blood pressure, and eaten foods with plenty of the other electrolytes. Since my 50-day bedrest, I also started taking extra calcium supplements. Since sodium can also cause excess calcium excretion through sweat and urine, you'd think I would increase it now.

But no... for the purposes of testing, I dropped them for a short time. As I draw closer to the first round of physical testing, the restrictions mean no vitamins, OTC meds or herbals, no alcohol or caffeine, no strenuous exercise and no heavy meals or complex carbs. Some of these are no trick at all, others are a serious change to my usual schedule.

And all week long: high sodium. It seems increasing it deliberately promotes many phenomena seen in spaceflight, along with dehydration symptoms. I already have the mild headache to prove this!

More to come...