Sweating the Small Stuff: Electrolytes

Sweating the Small Stuff: Electrolytes

 By Nuun Guest Blogger Jesse Kropelnicki of The Core Diet.

Even if you have never had a “cramping problem” in the past, neglecting electrolytes in training and racing could be compromising your results. Just like you wouldn’t wait until you were dehydrated to drink fluids, waiting until that first “cramp” is a signal from your body that your performance has been suffering for quite some time. Electrolytes play a crucial role in muscle function, adequate hydration status and digestion fluids during racing.

What is an electrolyte?

In medical or scientific terms, an electrolyte is “any compound that, in solution or in molten form, conducts electricity and is decomposed (electrolyzed) by it. It is an ionizable substance in solution.”

In other words, it’s a term for minerals that, when dissolved in water, break into positive or negative electrically-charged ions (anions or cations).

What are the functions of electrolytes?

Do you take electrolyte supplements before or after your run?

These ions carry electrical energy necessary for many functions in the human body, and optimal athletic performance requires adequate (and a consistent) supply of electrolytes. These ions move across membranes carrying fluids, nutrients and water. They aid in a number of processes that are important to an athlete:

  • Regulation of body fluids
  • Muscle contraction (including the heart)
  • Transmission of nerve impulses

However, repeated days of moderate or severe sweating can result in such substantial electrolyte loss, particularly sodium because of its high concentration of this mineral in sweat. When electrolytes are lost too quickly, the body does not have the ability to restore them as rapidly as they were lost. In these situations, dietary mineral intake is generally not sufficient to compensate for these large losses, and supplementation is needed to replace these electrolytes in order to maintain concentrations of body fluids.

What are the major electrolytes in the body and what do they do?

  • Sodium (Na+) – regulates total amount of water in the body
  • Potassium (K+) – regulates heartbeat and muscle function
  • Magnesium (Mg2+) – aids in muscle relaxation
  • Calcium (Ca2+) – aids in muscle contraction
  • Chloride (Cl-) – helps maintain a normal balance of body fluids

How are electrolytes lost?

Electrolytes are lost through urine and sweat. Endurance athletes can lose large volumes of sweat on a daily basis, which is accompanied by a similarly large electrolyte loss.  Each athlete has different electrolyte (and fluid) needs and environmental conditions of training and racing will factor into this.

  • Average sweat rate is typically 1 – 1.5L of fluid per hour (32 – 48 oz.) and 1,000 – 1,500 mg of sodium per hour while running (a bit less when cycling).
  • Most people’s sweat contains about 500mg of sodium per 16oz. Very salty sweaters can have up to about 1,500 mg per 16 oz. of sweat.
  • Sweat rate will depend on several factors including environmental conditions (temperature, humidity), genetics and the athletic fitness of the athlete.

Side Effects of Dehydration

In most cases, muscle cramping is related to either sodium or magnesium deficiency in athletes. If a deficiency occurs, cramps, tremors and spasm can be present. It is the Core Diet’s experience that acute occurrence of cramps during racing is typically due to sodium loss, and more chronic cramping (even between activity, during swimming or while sleeping) is typically due to magnesium deficiency. Another sign of sodium related cramping is a sloshy stomach. Another electrolyte, magnesium, is key in avoiding muscle spasms. A muscle “twitch” is usually a sign of low magnesium levels. Having proper sodium balance during digestion is important to fluid absorption.

Have you ever felt tingling fingers during your racing? If you have, you probably are experiencing a potassium deficiency. Many times a simple half banana available on many race courses can fix this problem before it impacts race performance.

How to replenish electrolytes?

Electrolytes help to increase the absorption of fluids into the bloodstream, and your muscular system operates efficiently which is why the best hydration plan is one that includes these minerals. Using products such as Nuun Active Hydration (electrolyte-enhanced drink tablets) before, during, and after workouts can go a long way to replenish electrolytes and achieve your best performance.

Nuun provides great-tasting active hydration.

About Nuun

Nuun is a great tasting on-the-go hydration tablet with the electrolytes you need to hydrate and re-fuel, but none of the sugar and junk found in sugary sports drinks. Nuun is available in over 5,000 stores in the U.S. and in over 30 countries. Visit nuunlife.com to learn more.

About The Core Diet

Jesse Kropelnicki is an elite triathlon coach and founder of TheCoreDiet.com, a leading provider of sports nutrition. He coaches professional triathletes Caitlin Snow, Ethan Brown, and Pedro Gomes with quantitative training and nutrition protocols. Track Jesse’s coaching strategies tips on his blog at kropelnicki.com.

Jaime Windrow is a Registered Dietitian and the Nutrition Programs Director at TheCoreDiet.com. Jaime’s interest in sports nutrition began when she danced professionally for 12 years with the Radio City Rockettes, and continued when she began to race in triathlons as an elite amateur. Jamie holds a number of age-group wins and podium finishes, as well as a finish in Kona at the Ironman World Championships.

Garmin Forerunner 10 (FR10) Review: Great Performance in a Small, Low-Priced Package

FR10 Orange

Following is a review of some Garmin products.  This is not my review, but I wanted to share it with my readers because I use a Garmin Forerunner 110 and think it’s one of the best tools someone who’s training for a marathon can buy.

The Garmin products are easy to use and upload to Garmin’s cloud.  This way you can accurately track the distance, time, heart rate, pace and more during your workouts.

Fortunately, Garmin provides different watches at various price points.  My hope is that this review will help you make a decision about which watch to purchase.

Enjoy the review, please let me know if you have any questions.


One of the first reviews I wrote here on Runblogger was of the Garmin Forerunner 205 GPS watch. That was way back in April of 2009! I loved the 205, and it was a mainstay on my wrist for a long time. It tracked distance and pace accurately, provided a ton of customization options on its large screen, and the battery seemed to last forever. On the downside, the 205 was huge! It was not a watch that you’d wear around all day.

Last Christmas I finally upgraded to the Garmin Forerunner 610. From a functional standpoint, the 610 does pretty much everything the 205 does (with the exception of crazy long battery life), but does so in a smaller form factor that can stay on my wrist all day (no more swapping watches for workouts!).

I’ll have a review of the 610 coming soon, but I started this review with mentions of the 205 and 610 to make a point. When it comes to GPS watches, I’m a Garmin fan. I’ve tried watches from other brands, but none of them have yet satisfied my needs as well as Garmin watches do. A big part of that is that I can easily import Garmin data into Dailymile.com and Sporttracks, which are the two places I sync my running data. That fact alone has kept me loyal to Garmin.

A few weeks ago I entered a affiliate partnership with Clever Training whereby they’d occasionally provide me review samples of products that they carry (you can get 10% off most purchases at Clever Training by using the code RunBlogXJT – purchases support this site and allow me to write in-depth reviews like this one!). Here’s how it works – they send me a product, I try it out, write a review, then send it back to them. Their suggestion for a first review was the Garmin Forerunner 10 (FR10) GPS watch. I agreed to try it out, and have been using it for the last several weeks.

The FR10 is essentially the “entry-level” GPS watch in the Garmin lineup. I was initially skeptical about it as my experience with other more basic GPS watches has not been great (e.g., Soleus 1.0, Timex Run Trainer 1). They tend to lack the functionality that I look for, current pace tracking has been iffy, and easy export of data to my preferred sites/programs was lacking.

I’d read a few reviews of the FR10 which discussed its limitations, and I wasn’t sure I was going to like it. At $129.99 MSRP it’s the cheapest GPS enabled watch in Garmin’s lineup, and it lacks the customizability of siblings like the 205, 610, and so on. However, I’ve come to realize that the simplicity of the FR10 is its biggest strength, and I’ve actually been blown away by this little device. It pains me that I have to send it back!

Let’s dig into the review.

Size/Form Factor

First and foremost, compared to other GPS watches the Forerunner 10 is small. In fact, it’s not a whole lot bigger than a standard stopwatch that has no GPS. If you saw it on somebody’s wrist, you’d be hard-pressed to identify it as a GPS-enabled device.

IMG_2185[1] From left to right: Garmin Forerunner 610, FR10, and FR205. My cat Mokey seems to like the FR10 best, and the 610 still thinks it’s in Oregon.



Garmin Forerunner 10 colors

Not only is its form-factor compact, the FR10 is also very light. My Garmin 205 and 610 weigh 2.8oz each, and the FR10 is only 1.5oz, and the difference is noticeable when wearing it on your wrist. It’s a super comfortable watch for all-day wear – hand’s down the best option I have tried for a GPS watch that stays out of the way. The FR10 also comes in a slightly smaller form factor for women with black, pink, green, and violet as color options (see photo at left).


In terms of menu navigation, the FR10 is as simple as it gets, and this is a huge plus. I like my FR610, but the touch screen isn’t very user friendly and there are a ton of menus to sift through. The FR10 has only 4 buttons, and they are intuitive and super easy to use. On the top left is a backlight button. On the top right is a button that serves to initiate a workout and functions as the “enter key” in menus. Bottom left is a back button, and bottom right is the button you use to pull up and scroll menus. Simple!

FR10 Orange

I was most worried with how the FR10 would handle my data needs on the run. I loved the 205 because it had a big screen and I could configure the 4 data fields to show just about anything I wanted. I could also toggle between three separate screens, so that allowed 12 fields total! More than anyone really needs on the run, but I’m a data junkie. The FR10 limits you to only two data screens, each of which displays only two data fields. But, because there are only two fields, the text is large and easy to read.

There are 6 data field combos that can be shown on each screen: Time/Distance, Time/Pace, Time/Calories, Pace/Distance, Pace/Calories, Distance/Calories. You get to choose two of these via the Run Options—>Data Fields menu on the watch.


Sampling of data field display options

There is an additional level of customization for the Pace field. In the Run Options—>Pace/Speed menu you can configure the Pace field to show any of the following: Current Pace, Lap Pace, Average Pace, Speed, Lap Speed, Average Speed. You only get to choose one, so you can’t have one data screen show Current Pace and another show Average Pace. I mainly use Current Pace, and I have auto-lap enabled so after each mile it spits out my lap time, so it gives me what I need.

Other menus include a nice History menu that allows you to view your data from each run (see photo below), and a Records menu that records your fasted time at the mile, 5K, 10K, Half-Marathon, and Marathon distances (also longest run). In the Run Options menu there is a Virtual Pacer that allows you to set a target pace and get alerted if you deviate, and a Run-Walk/Interval option where you can set run times and walk/recovery times. You can also turn on/off a manual lap button (lower left button during a workout).


Summary data from yesterday’s 10 mile run


I’ve used the Garmin Forerunner 10 on almost every run for the past several weeks. I even wore it when I ran the Vermont City Marathon a few weeks ago, with the FR610 on the other wrist for comparative purposes. I did another 10 mile run with both watches yesterday for a final test.

I have to say that I’ve fallen in love with this watch – when wearing both the FR10 and FR610 I often find myself looking at the FR10 more often than I look at the FR610. If it weren’t for just a few missing features (e.g., wireless data transfer, better interval workout capability, foot-pod sync) I’d consider selling my 610 on Ebay and buying FR10’s for myself and my wife.

As I mentioned above, my main data screen on the FR10 while I run displays current pace and distance. I have Time/Pace on the second screen. For the majority of runners that’s all that’s really necessary. Most of the time that’s all that I need as well.

What I love most about the FR10 is that the current pace readout is rock-solid. It reports pace in 5 second increments, so 8:00/mile, 8:05/mile, 8:10/mile etc. At first I didn’t think I’d like this, but what it accomplishes is a lot less fluctuation in current pace readout (and let’s be serious, current pace readouts on GPS watches probably aren’t accurate to the second). When running my marathon, I relied on the FR10 almost exclusively for real-time pacing and used the FR610 for it’s lap display (the main reason why I’ll keep it – being able to display lap time, lap distance, current pace, and lap pace all on one screen).

I have found tracking accuracy in the FR10 to be right in line with the much more expensive FR610. In fact, the FR10 measured the Vermont City Marathon course more closely than the 610 (26.37 miles for the FR10 vs. 26.48 miles for the 610 – need to work on running those tangents!). On my 10 miler yesterday, the FR10 measured 10.13 miles at an average pace of 8:22/mile, the 610 measured 10.12 miles at an average pace of 8:23. Pretty solid agreement! The Forerunner 10 has earned my complete confidence in its ability to track pace and distance.

The FR10 is rated at 5 hours of battery life with the GPS on, and it made it through my marathon no problem. It’s not the life that my old 205 had (I swear that thing had a Prius battery in it and recharged while I ran), but it’s sufficient for my needs up to now.

My only performance complaint about the FR10 is that it tends to not track that well under dense tree-cover (few watches that I have used do this well). If ultras are your thing, the combo of 5-hour battery life while recording and sub-par forest performance mean you should look elsewhere.

One other thing to note – as an entry-level watch the FR10 does not include a heart rate monitor. I don’t generally use a heart rate monitor, so no big deal for me.

Data Export

As mentioned above I use Dailymile.com and Sporttracks to store my run data. The FR10 syncs with both without a problem. I’ve also started using Garmin Connect a bit and really like it. If I hadn’t been using Sportracks for years I might even consider using Garmin Connect as my main run storage location. Below is a sample screen from Garmin Connect showing the FR10 recording of my run at the Vermont City Marathon:

VCM Garmin FR10

As an entry-level watch, the FR10 does not upload wirelessly (I like this feature of the 610). It connects via a USB cable that snaps securely into place on the back of the watch.


Garmin FR10 – Sync Cable and Back of Watch


Garmin FR10 – Sync Cable

The only data I typically look at that is not recorded on-board the FR10 is elevation (e.g., you can’t get elevation in SportTracks). However, when you upload the data from the watch to Garmin Connect you can view an elevation profile that is based on your GPS track (I suppose similar to how a site like MapMyRun or GMap Pedometer computes elevation profiles when you create a route manually on a map). Otherwise the data I get in Sporttracks is essentially the same as the data I get from the 610.


Given the fact that the Garmin Forerunner 10 is positioned as an entry-level GPS watch, I wasn’t expecting to love it as much as I do. Everything that it does, it does well, and for the majority of my runs it’s really all that I need. The only place it falls behind a bit is when I need more detailed lap data for an interval workout. Other than that, I could easily see using this is my full-time GPS watch, and given how much smaller and lighter it is than the FR610, I’m half-tempted to buy one for myself as an all-day watch and save the FR610 for more complex workouts (though I’d have a hard time justifying that purchase to my wife!).

The FR10 is an ideal GPS watch for a beginning runner, and for the experienced runner who doesn’t much care about anything besides how fast and far they ran, it is an equally good choice. At $129.99 MSRP the price is right as well.

Big thumbs up for the Garmin Forerunner 10

The Garmin Forerunner 10 is available for purchase at Clever Training in the colors seen below. Clever Training specializes in fitness electronics, and has agreed to provide a 10% off discount to Runblogger readers on most products that they carry – just enter the code RunBlogXJT at checkout. Purchases support this site and help me to write reviews like this one. Your support is very much appreciated! This article was originally posted by Peter Larson on Runblogger.com.