Hello Runner,
Welcome back to your weekly moment of endurance nutrition!
Happy Weekend!
How was your week?
Mine went by VERY quickly and was a mixture of emotions!
Last Sunday, I had a medical procedure that left me bedridden for two days. It was something I had been expecting, and I knew it would take a while to recover. In fact, I haven't been training 100% for a few days now, and I haven't been running for two weeks... all because of this procedure.
On Tuesday, I took the flight back to Barcelona and returned home. I'm still in the recovery process, slowly getting back into my routine, suffering from jet lag, and hoping that all of this will pass soon! For now, I'm continuing with light-weight training, Pilates, and low-impact cardio.
My body is asking for rest, and I must respect that.
One of the shocks I had arriving in Spain was the heat. I already knew it was going to be a big change... after all, I was leaving winter behind for the European summer/heat waves.
And you can't talk about summer without mentioning hydration—not that we should only worry about hydration in the summer! However, it is now extremely important to pay attention to hydration before, during, and after races.
It's always the same story during the summer: You train/run. Your T-shirt gets soaked.
But do you know how much water you've actually lost?
Most runners don't know — and drink water by guess.
But everybody loses sweat differently. And that changes everything in your performance.
What is sweat loss — and why does it matter?
Every runner has a different sweat rate.
It depends on the weather, your training, the intensity, and your body.
When you lose too much fluid and don't replace it properly, your body slows down:
➤ drop in pace
➤ feeling of weakness
➤ cramps or pain
➤ difficulty recovering after training
Now here's the best part: you can measure this easily at home.
CALCULATION
How to calculate your sweat loss (step by step)
Grab some paper, a pen, and a scale.
Do this before and after a workout.
1- Go to the bathroom and weigh yourself without clothes before your workout
2- Perform your training
3- Record exactly how much you ate and drank
This is easy if you drink from a single bottle or two
Weigh your bottles before (That’s X) and after (Y) and record the difference. 1 gram = 1 millilitre.* (Z)
4- After your run, dry yourself off and weigh yourself again
5- Now subtract your post-exercise weight (B) from your pre-exercise weight (A) to get the weight you lost during the session.
Weight lost (C) = A-B
6- Also subtract the weight of any fuel and hydration by weighing your bottle(s) and food before (X) and after (Y) to obtain the amount you consumed (Z).
Weight of fuel and hydration consumed (Z) = X-Y
7- You can now calculate your sweat rate…
(C+Z) * your exercise duration (in minutes)/60 minutes.
Note: Do a 60- to 90-minute workout. Try to avoid using the bathroom during your workout, as this can interfere with your results.
Calculation method adapted from Asker Jeukendrup.
What to do with this information
Now that you know how much you lose, you can plan how much you need to replace.
Before training: start hydrated (drink ~300–500ml 2 hours before). Avoid drinking too much close to the race/training session so you don't have to go to the toilet.
During (if >1h): Drink 150-200ml every 15-20 minutes or 500-600ml per hour.
After: Replenish the rest + electrolytes if necessary.
⚠️ Tip: if you lose a lot (>1.5L/h), you need a strategy with electrolytes (especially sodium).
Proper hydration is not just about drinking water — it's about understanding your body.
A well-hydrated runner does not run “drier.”
They run more consistently, more safely, and with less suffering.
-> If you want to learn how to adapt your diet and hydration to perform better and crash less, my 1:1 consulting service still has openings this month.
Reply with “I want to know more” and I'll explain how it works.
Track of the week 🎧️
This week's Track of the Week it's a rock classic. I still remember when the music video came out (yes, I'm from the era when I used to watch MTV to see music videos!) and I fell in love with the song and the video.
It's a great song to put on your running playlist to give you the boost you need.
I've chosen the track Jaded by Aerosmith.
Any questions or something you would like to share, drop me an email
Wishing you a great weekend and week ahead!
Here’s to health and good runs⚡️
Ana Paula Alonso