Science Series 41: Electrolytes and Me

As I approached mile 17 of the 2009 NYC Marathon, my legs began to cramp up. I blamed my lack of training and my dislike of Gatorade. In 2010, I was well trained for the marathon, took in more Gatorade and salt. My legs still cramped. Why is that? Let's break it down (Stop, Hammer time).

Somewhere after mile 18, MP paces me as I fight the pain.

Sources
These are the three primary sources I tapped. Thanks to the original authors and to all that have contributed to these theories I learned about.

health.howstuffworks.com
Active.com
Lore of Running, by Dr. Timothy Noakes

Muscle Cramps
A muscle cramp happens when your muscles involuntarily contract and/or expand when they are not supposed to. You'll generally notice this happening because it hurts like hell. Sometimes you can actually see the muscle spasm under your skin. There are only "theories" about what causes them. That basically means the scientific community isn't satisfied by the method of "proving" the causes. There are lots of anecdotes and little controlled clinical studies using the scientific method- you know, that thing we all learned in middle school chemistry class where some of you burned your hair with Bunsen burners.

The sports related theories are as follows:

Excess use of muscles/lack of conditioning- You work your muscles so much, firing off your neurons, contracting and expanding, to the point of which they are incapable of doing it any longer.

Dehydration/electrolyte depletion- Your body needs water and an appropriate balance of electrolytes to function.

Injury Defense- Something is injured and the muscle around the injury cramps in an attempt to protect it.

My cramps were not caused by injury, and based on the training that I did, I'm not willing to say I was under-conditioned for the race pace I set. So let's focus on the electrolytes.

Hurting. Me and that guy in the foreground too.

Electrolytes
Electrolytes are electrically charged ions that can move to either a positive or negative charge mainly do to the gain or loss of protons in its atomic structure. These electrolytes are important because your body uses these guys to carry electrical impulses throughout your body, including from your brain to your muscles. Cool, huh? So if you are electrolyte depleted, electrical pulses will not be carried properly and your muscles will not contract and/or expand when you ask them to. An individual needs about 8,000mg per day to function normally. Keep that figure in mind.

The main body electrolytes are:
* sodium (Na+)
* potassium (K+)
* chloride (Cl-)
* calcium (Ca2+)
* magnesium (Mg2+)
* bicarbonate (HCO3-)
* phosphate (PO42-)
* sulfate (SO42-)

Sodium and Chloride make up the majority of these electrolytes. They also form table salt (NaCl) when combined. Potassium is another that I will mention. The two primary electrolytes responsible for water content control in and out of cells in the body are sodium and potassium. While sodium generally exists outside the cell, potassium is found inside. Because of this, it is mainly sodium that is lost while sweating. The concentration of electrolytes differs by each individual and is also dependent on acclimation to climate condition. I'll be using average amount and assume the individual is acclimated.

Holding the line... the cramps will not beat me (just slow me down).

Mole to Mg Conversion
Does anyone remember how to do this from high school chemistry class? It's been a while. Sorry Mr. Zentz. I remember that a mole is a mole is a mole, as you used to say, but couldn't remember what the hell that meant. I had to look it up and still I cannot get my math to work out.

A mole (mol, or mmol for one thousandth of a mole ) can be converted to grams by multiplying the average atomic weight of the molecule by the mol amount. But I think other factors, such as ionization are important (ie, counting the extra protons). Rather than trying to teach you and myself this, I will be using the figures given in the Lore of Running book, by Dr. Tim Noakes.

Average electrolyte contents of sweat and blood.

Sweat Rate
So how much do we actually sweat? This is very individual. Again, assuming acclimation, the average runner sweats at lets say 1 liter per hour. Based on this, a runner could lose 1840mg of sodium and 100mg of potassium per hour. If you've never had problems with electrolytes during your runs, then this blog probably isn't really that interesting to you and you probably fit into this average. Alberto Salazar was recorded to sweat at a rate of 3.7 liters per hour. Yikes.

To measure your sweat rate, weigh yourself right before you run. Then run, and weigh yourself right after. One pound lost equals 15.4oz (.455 liters) of sweat. If you drink water during your run, be sure to add that as well.

So the last time I weighed myself before and after a run was in the spring of 2009. I lost 8lbs on a 90 minute run and drank about 12oz of water on my run.

8lbs= 3.64 liters of sweat
12oz of water = .4 liters
That adds up to about 4 liters of sweat in 90 minutes.
And that calculates to a rate of about 2.67 liters per hour.

Yup, I sweat a lot.

Turning on to Park Ave South, tasting the forgiveness.

Absorption Rate
So we should just take in the same amount of water and electrolytes as we lose? No. Definitely not. Ideally you'll take in just enough to get you through the race and you can replenish the rest after. You know, so you stop less and carry less water. But there are other factors to consider, such as absorption rate. Our bodies can only process so much at a time- there is a limit to the amount of water, electrolytes, and calories we can take in per hour.

What is that limit? I'm glad you asked. Again, it is individual. And there are different theories about what the body is capable of. It is thought that combining the right ratios of water, carbohydrates, and electrolytes will will optimize absorption. Check out this theorized ideal combo:

ideal fuel ratios

Sorry I didn't calculate the mg of Carbs from the mmol figure above, but the source didn't give its chemical equation. Studies show that because these different elements are absorbed in different places in the digestive track (ie, water in the stomach) the ratio changes as digestion happens. This actually allows for even higher rates of absorption. Anyone else out there think that's kind of cool? To find your individual rate, all I can offer is trial and error. Just see what you can do, within the scope of what you need to do (ie, don't try to drink a gallon of salt water if you're not showing signs of dehydration and electrolyte depletion).
Now compare the electrolyte content of sweat and the absorption rates and ratios to the electrolyte amounts in popular sports drinks. Since sodium is the primary electrolyte lost, let's focus on it.

electrolyte content

Lacking, huh? I want to give props to Gatorade for even starting this trend of electrolyte replenishment. But they're not going to change their formula if it makes their drink taste bad (or worse than it already does). Above is the figure for their endurance formula. Their normal stuff is much worse. From these figures, one could easily argue the content should be at least twice what it is. So I take salt, as I'm sure many of you do. And I drink V8 regularly during the week and for recovery- criticized for high sodium content, this is quite ideal for runners, as is the tons of potassium and other goodies.

Aldosterone: Less is more?
How one should preemptively take in electrolytes is debated. Your body regulates your electrolyte balance with something called aldosterone. If you need electrolytes, aldosterone will up the amount in your body. If you have too much, it will turn off. So eating salty foods encourages the aldosterone to stop doing its job. And you are potentially acting against your own natural physiology. But when exercising, you lose more electrolytes than your body can manage.

How do we reconcile this? Again, I'm not finding a definitive answer. My advice would be that if you take in electrolytes early, you should continue to do so throughout your run and after, restoring your levels "manually" while your aldosterone kicks back in. And at the appropriate ratios too.

Victory. But I know I have an even better time in me.

Mistakes and Lessons

So here's the math of my 2010 NYC Marathon. At a sweat rate of 2.67 liters per hour, I was losing 4,913mg of sodium per hour. I was taking in about 300mg of sodium per hour via Gatorade & Gu up until I took in 1,500mg of salt (perhaps 2/3 of which is sodium versus 1/3 of which is chloride) at mile 15. I reached mile 16 in about 2 hours and that's when the cramps started.

Me by mile 16:
9,826mg of sodium lost
1,600mg of sodium gained
That equates to approx 8,200mg net sodium lost
Remember the amount needed daily for normal body function? About 8,000mg.
Oops.

The average sweaty person would have lost about 4,000mg of sodium netting a loss of 2400mg. Manageable. I should have taken in more sodium and sooner. There's still a concern that my absorption rate may not be able to handle it- my feet may be too fast for my digestion. Kind of funny. But only kind of. I 'll have to test this. But even if I was average and took in 2,800mg of sodium per liter of water per hour, I should be perfectly fine in the marathon distance.

Something else... Coconut water, loaded with potassium but little sodium, isn't the ultimate electrolyte gift from God I thought it was. I thought sodium and potassium were interchangeable, but as you and I now know, they are not. I drank a lot of it thinking I was prepping appropriately. For electrolytes lost via sweat, salt rules.

And my final lesson... I am a really big running geek. Oh wait.... I already knew that.

So now I take a break, letting my calf heal properly from the injury that was probably caused by cramping 2 weeks before the NYC Marathon. Hopefully by late December I will be able to apply some of these theories, and by May put all this science to the test. Look out Fargo 2011. Here I come.

The 41st Running

3:29:06. That was my time at this year's NYC Marathon. Not a Boston Qualifying time, but it is a PR by 20 minutes. Yeah, I had a calf issue. But bottom line, I didn't have a 3:10 in me. Let's recap this painful, yet glorious event.

"Your calf feels more like a pull." Leslie, my sports massage therapist broke the news to me. I had hoped it was just a knot of some sort that needed to be worked out. I walked gingerly home and took the prescribed epsom salt bath, pondering how my week would go. The compression socks I ordered arrived that day. I would spend most of that week in them. I wouldn't be running until if felt better or the marathon Sunday came, which ever was first. I had 8 days. By Tuesday it did not feel better, so I made an appointment at Finishline PT to get some more advice. Coach Michael has helped me through other injuries and events, including last year's NYC Marathon, and I was counting on the same magic.

Rocking the expo with Syed, Jim, and TNT Elvis

"I don't feel any scar tissue or separation in your muscle," Coach Michael declaired. This was fairly good news. Was my pain just in my head? Definitely not. But it implied the injury was minor. I asked about permanent damage. I was really hoping to be pain free by Sunday, but worst case scenario- if I were to run on it, would I do any permanent damage? "No. You'll be fine. You'll just feel pain. It may warm up and go away." Relief.

"You know what you should do? Dunk your whole leg in ice for 25 minutes every day until the race. That's what I would do." Bart Yasso has quite a bit of experience running through pain, so I heeded his advice. I stopped by the Runner's World booth to purchase my own copy of his book and get it signed. I couldn't help but mention my ailment. I went home that night and wrapped my calf with a large ice pack and did that again on Friday. Saturday, I did it 3 times.

Icing le calf on Saturday night

Sunday I woke up with my calf aching. Not good. But oh well. With Finish Line's blessing, I had no intention of sitting this one out. I got into my gear, and my "throw-away" warm clothes, grabbed my bag, and headed out the door toward the park to meet the Team bus that would take us to Staten Island. I was calm. I had been for a few days. Friends had asked if I was excited and I would hesitate a bit and say either "yes" or "no". You know, I was excited, but I wasn't jumping out of my shoes in excitement. Riding that bus toward the Verrazano Bridge felt familiar. I reflected a bit on just how calm I felt. This would be my 4th marathon, my 2nd NYC marathon. Am I getting used to this type of thing? I’m not quite sure that was it. I couldn’t put my finger on it. It just felt right, like I belonged on that bus. I should be going to Staten Island on Marathon Sunday. What else would I do?

I chatted with some of the other participants on the bus. Murph, a leukemia survivor was aiming for a 3:30 finish. He was capable of going faster, but he factored in some family-hugging time. John, another survivor, was going for sub 3 hours. I admired both of their goals and race plans and admired their strength on so many levels. Their perspective on the race was optimistic. No matter what, it was going to be a great day. And their character- these two guys fought their battle with leukemia, and then joined TNT to fundraise and encourage others. To top it off, they were both quite athletic.

Pre-race lunch included jelly fish, cow stomach, roast pig, beef noodles, clams, chinese broccoli and more

We arrived at Marathon Village and before the team separated into their assigned color corrals, we exchanged hugs and good luck greetings. My group, green, settled on a nice patch of asphalt while we awaited our starting times. I was in wave 1 and would start off at 9:40. My plan was to finish in 3 hours and ten minutes, recover while walking to my bag truck at the finish, meet my family, eat a sandwich, and get my ass back out onto the course before our team’s waive 2 runners passed mile 23.5. No problem.

I sat on my sleeping bag, closed my eyes, and visualized the race for the last time. I played it out in my head, knowing I’d have to deal with some pain, mentally pulling back in the beginning so that I wouldn’t go out to fast, knowing that the end would be tough and I’d have to “hold the line”. That’s my mantra when running hard. Hold the line. It was soon time to line up at the start.

All bundled up, TNT waits patiently for the start.

In corral 6, I started taking off my many layers. First, off came the socks, then my sweat pants and the jacket. I had actually gone out and bought new sweatpants and a new jacket just to toss. Last year I was shivering because I didn’t have enough warm clothes. I don’t really have much in my closet I’m willing to part with. I didn’t want to make the same mistake again. I spent $17 on the winter coat and $7 on the sweatpants. And I ditched them where nyrr would pick them up and donate them. It was a well valued $24 donation.

I warmed up my calf a bit. It was tender. I contemplated taking the ibuprofen in my pocket, but didn’t do it. I looked around, sizing up the runners around me. It’s not really a competition against them- I’m not gonna win this thing- but I was wondering if they were the type that goes out too fast? Are the conservative in the beginning like I planned to be? You can’t really tell by looking, but I was trying. I was truly excited now. The gun went off and 52 seconds later I was crossing the start line. 52 seconds. I can honestly say that there was a point in the race where I was only 52 seconds behind the winner.

Steve captures me as I approach my family and friends on 4th ave.

My first mile split was 8:20- slower than I was planning which was great. Usually I find myself going too fast. Mile 2 was 7:10. That’s right on target. Up Fourth Avenue I was averaging about 7:20 which was a bit faster than I had planned- I was going for 7:25- but it’s Fourth Ave! With all the cheering and being on my home turf, that I was only about 5 seconds faster on average wasn’t too bad. Anthony and Shannon brought their son Braden to cheer all the way from the Jersey shore. Steve and Vicki brought their boy to support me as well. Lisa and Amanda also made it out. And my family came down from upstate to be there for me. Not to mention the TNT cheering! Wow! I saw Robyn at 6th Street and Laura at Baltic. That stretch, I ran a 7:05 split. Sure, it was too fast, but on average I did a good job reigning myself in and never hit my lactic threshold. Things were going quite well… kind of.

That calf of mine ached from the very first step. Specifically, it was painful when I landed on my midsole. I found myself heel striking immediately. Well, more than heel striking- I could feel the impact reverberate in my legs with every step. It was more like heel pounding. It wasn’t the Verrezano shaking; it was me. This did not bode well. I was killing my quads and favoring one side. I had to force myself to land more on my midsole- where it hurt. Getting into a consistent rhythm, while doing this, was difficult. I naturally wanted to avoid pain, of course. That’s when Lady Southpaw’s song "Every Step Together" popped in my head and stayed there throughout most of the race. At 166 beats per minute, it was helping me find a more efficient stride- almost as if the artist created it that way on purpose (she did). It established a rhythm that I couldn’t on my own and distracted me from the pain of each footfall.

TNT pumps me up!

Somewhere in Williamsburg, while Melka was hanging from a lamp post firing off an air horn in support, I was contemplating abandoning my goal. My legs were not feeling as fresh as they should have. After the Lafayette Street hill, around mile 9, my intention was to drop down to 7:10 splits. It wasn’t happening as easily as I was hoping. As I approached the Polaski Bridge and the half way point, I decided to back off. Today wasn’t going to be the day. I’ll still finish strong, just not a 3:10. Perhaps a 3:15.

I flew through Queens, passing more TNT stations and seeing Coach Steve. “How’s it going?” he asked me.

“I’m tired.” I replied with a smile.

“Well you look great!” I don’t know if he was sincere, but the encouragement felt good. As planned, I took it easy on the Queensboro Bridge. After cresting, I ingested a bunch of salt. This bridge, in my mind, is the defining point of the course. If you survive it, you’ll be ok. Well, maybe it’s not just me. Haile Gebrselassie had to pull up here because of his tendinitis. I think he knew it too. He didn’t survive. It was after the bridge, on my way up First Avenue, where my legs began cramping last year. Proactively, I drank more Gatorade early in the course and took in a lot of salt on the bridge, picking up speed as I descended.

Then, on First Avenue, my legs started cramping.

“What the hell?” I thought to myself. “What have I done wrong?” I still don’t have the answer to that. Though I took in more fluid and electrolytes than I did last year, my legs were cramping even earlier in the race. I slowed down. I was expecting to find my family along First Avenue, so I used that as a mental excuse to why I was going slower. I was nervous. This wasn’t supposed to be happening. I looked for their faces. “What am I going to do?” I looked for their signs. “Where’s the next water station?” I couldn’t find them. “I’m going to miss them…”

Suddenly MP popped out on the course. “Hey man, how’s it going?” This is the same MP I did the NPT hike with. The same MP I planned on doing Boston with. The same MP that I will be doing Comrades with. And he lives in Berkeley, CA. He has a habit of showing up three thousand miles away when least expected. He does it so much it’s not really a surprise any more. He’s crazy. I love this guy.

“Hey MP. I’m hurting.” He ran with me. I needed it. Just as I did last year, I started double fisting water and Gatorade. I have to keep these cramps at bay. It was just my left hamstring at first, but soon, both hamstrings, both calves, and my left quad were all cramping. That original calf issue? Yeah, I didn’t feel that anymore.

Coach Pete ran with us a bit heading up to The Bronx. I received cheers all the way up First Avenue from a bunch of familiar and friendly faces. It’s a pretty amazing thing, being part of TNT and running in NYC. I felt like the mayor. I felt like everyone in town knew me. It really was great support.

MP kept me moving forward at a fairly consistent pace of 8:00 per mile, maybe a bit slower than that. I had stopped looking at my watch miles ago. I was fighting those cramps as best I could, but didn’t think I could maintain till the end. As we approached the 5th Avenue Bridge, I let MP know I was going to stop and stretch just after the 21 mile marker. This is where I stopped a year ago to talk with my legs and I was going to do it again.

“Thanks guys. You’re doing great. We’ll figure this out.” I was thinking about why I was cramping so badly. “I gonna push you. I need to you hold on. Hold the line.” I had no intention of backing off as I had last year. My energy level was good. I wasn’t breathing hard, my legs didn’t feel heavy. They were just seizing up. MP waited patiently as I had my two minute stretch session and pep talk. Starting again was hard, but I managed to find a rhythm after a few minutes. MP hung with me until 111th Street. He had a flight to catch. Yeah, he arrived Saturday night and was flying out Sunday evening. He came in running shoes and a fuel belt loaded with amenities. He came for me, just in case I needed him. Did I mention I love this guy?

More friendly faces and TNT cheers along First Avenue encouraged me to finish strong. I pushed up the incline at mile 23 and then started looking for my family. I had missed them on First Avenue, MP confirmed. They were out there for me. I had to be sure to see them. And there they were, at 91st Street, looking for me. I ran by waiving and calling for them, but they didn’t see or hear me. So I stopped, and walked back to them.

“Hey guys, how’s it going?” I said nonchalantly.

“Where did you come from?!” My sister asked in surprise.

“You know, just hanging around.” I walked up to my mom and gave her a big hug. I was inspired my Murph. This was a good idea. I greeted all of my family and thanked them for being here. “Ok, I’m gonna go finish this thing.”

“Do you want the pain killer stuff?” My sister called out. I had her hold some capsaicin just in case.

“No. There’s no holding back the pain now!” I thanked her anyways and took off.

I found the line and I held onto it, pulling harder and running faster. These cramps would not stop me. I was determined. I looked into the crowds and listened to the cheers for TNT. Central Park South was amazing, packed with people supporting us. I was passing a lot of runners- the exact opposite of last year. That felt good. I saw the 800 meter sign. “Yasso,” I thought to myself. I could do this last stretch in 3 minutes if I hold the line. I picked up the pace. The cramps were quite strong, but I was stronger. 400 Meters. We turned into Central Park and that last bit of a hill greeted us. I greeted it back by running faster. I could see the clock at the finish. I ran even faster. I looked up and took in the crowd. I raised my arms in victory as I crossed the finish line.

“Yeah!” I clapped my hands together in approval of the accomplishment and exchanged pleasantries with the runners who finished next to me. I immediately thought to myself, “I want to do this again next year.”

--------------------

Recovering with John P.

It took quite a while for my legs to stop cramping. After retrieving my bag, I happened to find John from my Warriors team. He had also just finished and was recovering. I sat with him for a spell, changed into my TNT Coach shirt and made my way to where my family was waiting. I couldn’t run. Walking was challenging. There was no way I could get on the course and run with any participants. But after meeting up with my family and eating a ham sandwich, I stayed on the course to cheer and support. By this time, I had missed all of waive 2 and the beginning of waive three.

I didn’t leave the park until 7 pm or so, cheering on those still finishing up their marathon and waiting on a couple TNT participants from Brooklyn, Carmen and Jenique. It was a long day, but a triumphant one. I’m proud to have been part of this TNT season.