Nutrition & Exercise Part 3: Lab

Sweat it out, babyThe last post was all about how to fuel your body during a workout. Carbs are important for a workout lasting longer than 45 minutes – but I don’t have time for an hour-long workout today 🙂 So now that we know all about sweat ratios – let’s apply that instead.

Knowing your sweat rate is helpful because it gives you an idea of how much water you should be drinking during a workout to prevent dehydration. Remember, dehydration defined as losing more than 2% of your body weight during exercise

sweat rate

Want to figure out your sweat rate? Let’s calculate (nerd alert)

 Step 1:

Before one of my HIIT exercises (this one was in the afternoon, not at 5 am because my military man was traveling for work) I weighed myself.pre exercise weight


Step 2:

Get ready. Get your water bottle handy and make sure you know how much fluid you are starting with. Here is a photo of my water bottle. It’s good to have a large water bottle with measurements on it so you can see the quantity.

Step 3:

Work it out. Put on an awesome playlist (I love Spotify’s abundance of exercise playlists) and get to it. I had a few interruptions from my 4-year-old during this one, but luckily they were short and sweet, just like him 🙂 Drink water during your exercise to help stay hydrated and prevent fatigue. Here is a photo of my exercise plan, in case anyone was wondering. Read more about HIIT exercise here.

Step 4:

After the workout, immediately weigh yourself again. Note the amount of water left in your water bottle and write down your pre-exercise weight, post-exercise weight, the length of workout in hours and ounces of fluids you drank during your exercise weight

Step 5:

Grab your calculator. Let’s compute! Multiply your weight in pounds by 16 (16 ounces in a pound of sweat loss) to get your weight in ounces. Then it’s just plug-and-chug:

sweat rate

OK, so what is the point?

This equation is to give you an idea of how much fluid you should be consuming during a workout. According to my equation, I lose 64 ounces of sweat during one hour of HIIT exercise (32 ounces during my 30-minute workout).

Does this make sense? It’s not always possible to replace all of the fluids you lose during a workout – and sometimes it’s not even necessary. A sweat rate is more so as a point of reference – to give you an idea of the importance of replacing fluid loss.


As I mentioned earlier, dehydration is considered a >2% body weight loss. Since I lost 1# during my 30-minute workout from sweating, my % body weight loss is 0.8% – not near the dehydration benchmark. (weight loss/beginning weight or 1/121.4 in my case) If you are losing more than 2% of your body weight, it’s definitely time to replace those fluids!

I hope this helps. Knowledge is power and the more you know about your own body and your own sweat, the better you can prepare yourself to stay hydrated.

Happy hump day!