Sodium and Sweat

During normal daily life, including my usual weekday workouts of 60minutes or less, I don't worry too much about sodium/magnesium/potassium as separate intake elements to be measured. If it's hot, I'll sometimes use an electrolyte drink instead of water.

That approach changes during longer sessions, typically on weekends. Since my swim, bike and run sessions can be long (eg 4-5 hrs for a bike/run combo) I'm very focused on both hydration and calories.

I use Precision Hydration 1500 powder or tablets on the bike. I've taken their online sweat test/profile and follow their protocol especially during warm humid weeks. So a typical plan is to consume a 20oz water bottle w/PH1500 on Friday evening, then another bottle on Sat am before the long session. That way I have plenty of electrolytes in my system at the start, then 1 bottle/hr intra-workout. I'll then often consume one bottle of water and one more of electrolytes after a long ride/run.

The goal is to replenish both fluids and electrolytes as quickly as possible during recovery to prepare for the next day's effort. The PH website has some good information on sweat rates, etc, if you are active in endurance training.

COGypsy wrote: »

I’m curious about “accurately measuring” sweat. How does that work? How do you account for evaporation? I’ve never heard of or thought about calculating sweat as a nutrition factor.

Weighing yourself before and after the workout is one option. In the calculation, include the weight of the water/fluid consumed between starting and ending weight.

Sweat is a health and performance factor, for sure. I'm not sure if I'd think of it as a nutrition factor, but that's splitting rhetorical hairs.

I'm not as structured as @Djproulx (who's IMO giving excellent technical advice here), but I do add electrolytes and of course manage hydration more thoughtfully during hot-conditions exercise, especially longer duration exercise (loosely, > 1 hour).

COGypsy wrote: »

I’m curious about “accurately measuring” sweat. How does that work? How do you account for evaporation? I’ve never heard of or thought about calculating sweat as a nutrition factor.

That's a good point.
Weighing before/after extended exercise sessions only really gives you a good guide to the amount of rehydration required and doesn't tell you how much was water vapour breathed out and how much was sweat.

Personally I only feel the need to supplement with electrolytes for long (multi-hour) or hot weather exercise when it tends to be half my fluid intake has added electrolyte tablets.
If I get it "wrong" I get clear salt cravings.

I've never measured anything, but when I was trying low sodium I was frequently cramping up during and after exercise, particularly in the summer. My shirts were often caked with salt from sweat. I'm hypertensive so I was trying to lower my sodium, but it didn't seem to be making much difference anyway. I went to see my Dr. about the cramping issues as well as just not feeling all that great and he told me to up my sodium, just not go overboard with it. I don't remember the exact range I came out to, but the cramping stopped and I felt a lot better...I think I was in the 3000 range or so. I also just kind of let my salt cravings be my guide...I'm actually not big on salt so it seemed to me that if I was craving it, there must be a reason.

autotech44 wrote: »

Djproulx wrote: »

Yeah, given your description, I think you'll feel better by including sodium/electrolytes in the mix. If you're like me, you can produce a lot of sweat in an hour, especially during warm weather runs. I'll often notice that my eyes start to sting from salty sweat and/or I have cravings for salty foods.

Of course, the structured approach becomes more helpful or necessary in situations such as @sijomial describes.

I always get the burning eyes and salt rings on my shirt and hat. And I'm sweating significantly more since I upped the sodium.

I discovered a good quick salt fix. Pimento stuffed olives. 230mg/20 calories each.

Those sound great. (Now I'm getting hungry).

A few of us carry the fast food restaurant salt packets in our run vests as a backup to our liquid sodium sources. Salted pretzels, chicken broth and pickle juice are the most popular options on the run courses at many triathlons.