NOW Ca&Mg tablets: 500mg Mg, 1000mg Ca per 2 tablets
TUMS: 1000mg calcium carbonate
Coconut water: 50mg Na, 646mg K, 24mg Mg, 53mg Ca, 15g carb
"Astronaut Juice": 145mg Na, 12.5g carb per 8 oz serving
Coca-Cola: 40mg Na, 42g carb
Pickle Juice shot: 470mg Na, 20mg K, 2mg Zn, 0g carb
Nerds gummy clusters: 15mg sodium, 71g carb
Gu: 55mg Na, 30mg K, 20mg Ca, 23g carb
Clif bloks (3): 50mg Na, 18mg K, 24g carb
Biscoff (4 cookies): 115mg Na, 23g carb
Stroopwafel: 75mg Na, 18g carb
Clif bar: 230mg Na, 225mg K, 40mg Ca, 42g carb
McDonald's salt packet: 280mg Na
Heinz mustard packet: 65mg Na
For me, learning about electrolytes has been a trial-and-error process. When you train with a friend or a group, someone will see you suffering and lean over to whisper about their favorite bonk-breaker. I was told about Gu from a running friend when the mileage climbed above 9 miles for a long run. We would stop to take a gel at mile 7. I remember refilling a water bottle during a 60-mile bike ride in 2010, and someone quietly slipping a Nuun tablet into my bottle. At the time, I was primarily concerned with drinking water, and I thought it was enough to quench my thirst.
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| Marty's Tom's Farms ride |
When I was hiking in the Verdugos, I got food poisoning in 2012 from my own self. I had probably put a Nuun tablet into a hydration bladder and then let it fester. The next time I tried to use it, it was full of pests, which infested my GI tract. I vowed then and there to NEVER contaminate my hydration bladder again. I've heard people put flat Coca-Cola into their water bottles, so I've added Coke for comparison. But I'm too scared of not being able to fully wash it out to put anything other than water in my hydration vest/belt bottles. I remember examining Nuun's ingredients, and in terms of macronutrients and micronutrients, it was similar to the growth medium used to culture fungi.
The kicker for me came when I cramped during the 2024 Santa Monica Classic. I called my sister to complain, and she asked me what type of electrolytes I was taking. When I told her none, she said it was incredible that I lived in such a hot climate and that nobody had taught me about the importance of replenishing electrolytes. To be honest, every time I think about this race, it still burns me that I skipped the 10k and only finished a 5k. The course was shortened due to the heat.
I've been wanting to write a blog about salt for a long time, but it seems like I'm always staying so busy. I had to take a break from grading student work because hackers disrupted our access to the LMS, Canvas. It's been unavailable for just over 24 hours, which is pretty much the timeline I predicted. But it still sucks that I lost about 8 hours of productivity. Although it did give me the opportunity to write and read a little about salt.
What I can say is that during the 2025 LA Marathon, I took two SaltStick chews every 30 minutes and ended up feeling gross at mile 17. I adjusted that to one SaltStick chew every 30 minutes in 2026, and it was perfect. I felt amazing up until mile 25.
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| MyFitnessPal all time data |
LA Road Runners Chat #9 Dietition Serena Marie - Part 2 (10-30-2025)
https://youtu.be/f5gXdJ4i4yQ?si=KmMON9FYyumPI4ux
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| LA Road Runners Thursday Night Coach's Zoom |
You can calculate your sweat rate, and a dietitian who spoke to my running club explained that you should track all of this, including the weather. To convert sweat rate to sodium loss, multiply your sweat volume (in liters) by your sweat sodium concentration (typically 200–2,300 mg/L, with an average of ~950 mg/L). A typical, moderate sweat rate is 1.2 L/h, which, at an average concentration, results in ~1,000 mg (1 gram) of sodium lost per hour. I've never done it, but maybe I can make this a summer project.
Sodium to Salt Conversion: 1 gram of sodium equals ~2.5 grams of salt (NaCl).
Range: Most people lose 200–2,300 mg of sodium per liter of sweat.
Factors: Sweat concentration is mostly genetic, but sweat volume depends on intensity, temperature, and acclimation. You can use this worksheet to calculate your sweat rate, then use that to determine how much sodium you need. I don't feel like I'm a heavy sweater, but at the Naughty Girl Fitness workout, I was dripping sweat, so maybe I just don't notice it when I'm running.
https://koreystringer-institute.media.uconn.edu/wp-content/uploads/sites/3814/2024/08/Sweat-Rate-Calculator.pdf
I am mindful that we need more magnesium as we age. I wonder how much magnesium from supplements is bioavailable. I still take a lot of supplements, pushing calcium and magnesium as I have since pregnancy and postpartum. But because of the cost, I sometimes wonder if I should stop. Also, I wonder if I'm putting myself at increased risk of kidney stones by overdoing it on electrolytes. In all, the body is pretty great at maintaining homeostasis. But I have heard of people overdosing on TUMS and ending up with stones.

I have heard of people taking salt packets from McDonald's, as well as mustard packets. Some people love Nerds gummy clusters. I guess I spent a lot on food/fuel when I was first getting started running, but now that I'm more settled on what I like (what works for me), I don't spend as much. I included fuel and all the food from the race weekend in this calculation. Someone in my running group suggested signing up for ALL the races. Like YOLO. They justified it by saying, "What is your health worth?" And that got me thinking about how much I spent on running in the past few years.
My previous posts about salt:
- CalorieCount https://bitchonabike.blogspot.com/2011/01/carbs-calcium-cortisol-oh-my.html
- Salt Bath https://bitchonabike.blogspot.com/2011/05/bathing-beauty.html
- Race Day https://bitchonabike.blogspot.com/2025/04/race-report-rose-bowl-half.html
- Immune System https://bitchonabike.blogspot.com/2011/10/airborne.html
- Fertility https://bitchonabike.blogspot.com/2019/03/fertility-part-3.html
- Supplements https://bitchonabike.blogspot.com/2020/07/turning-40.html
- https://bitchonabike.blogspot.com/2025/07/supplement.html
- https://bitchonabike.blogspot.com/2022/12/november-2022-thoughts.html
- During Training https://bitchonabike.blogspot.com/2024/12/women-are-not-small-men.html
- Century Rides https://bitchonabike.blogspot.com/2014/07/independence-day-ride-report.html
- https://bitchonabike.blogspot.com/2014/10/ride-report-r2r-california-challenge.html
- https://bitchonabike.blogspot.com/2013/12/christmas-ride-report.html
- Kaiser Wellness Posts https://kaiserwellnesscenter.blogspot.com/2013/05/coconut-water.html
- Astronaut Juice https://kaiserwellnesscenter.tumblr.com/post/50695781267/astronaut-juice
Other References:
By: Mazza, Elisa ; Maurotti, Samantha ; Ferro, Yvelise ; Castagna, Alberto ; Pujia, Carmelo; Sciacqua, Angela ; Pujia, Arturo; Montalcini, Tiziana. Nutrients (2025), 17(13), 2226.
Marco Gervasi, Davide Sisti, Stefano Amatori, Sabrina Donati Zeppa, Giosuè Annibalini, Giovanni Piccoli, Luciana Vallorani, Piero Benelli, Marco B L Rocchi, Elena Barbieri, Anna R Calavalle, Deborah Agostini, Carmela Fimognari, Vilberto Stocchi, Piero Sestili. J Int Soc Sports Nutr. (2020) Jan 20;17:6.



