Marc Casals Vilasis is a runner from Barcelona who lives in Brussels, Belgium. He's run a number of marathons and before 2018 had had two cracks at the iconic New York Marathon. 

His first attempt in 2015 was hampered by cramp and a loss of power at around the 20km (12 mile) point. He soldiered through for a time of 4:15.

He then came back for revenge in 2017, but the cramps struck again, this time at Central Park just after the 36km (22 mile) point. Again he pushed through and finished with a solid 03:46 on the clock.

But he knew he had a better time in him and was determined to get to the bottom of his issues with cramp. So he did a bit of research and ended up booking in for an Advanced Sweat Test - as well as a lactate threshold test - at our Sweat Test Center in Belgium (run by endurance coach Filip Rigole).

3 months later he toed the line in NYC again, only this time he had a personalised hydration plan and had preloaded on PH 1500 before the race. Not only did he finish the race without cramping up, he beat his previous marathon PB by no less than 19 minutes, crossing the line in 03:27.

We discussed the race - and Marc's Sweat Test - with Marc and Filip to get some insight into the prep that helped Marc achieve his goal...

So Marc, how many hours are you training per week in the key months before an event like the NYC Marathon?

MC: I usually hit the road 3 times per week, averaging about 4.5 hours a week, with some stretching before and after the session.

I did 1,100km in 2018, but as my coach Filip Rigole says, it's more about the quality of your kilometers than the total amount!

Indeed! Ok, so talk us through your history of problems with cramp, when were you suffering with it and what was the impact on your performance?

MC: Cramps always hit me hard in the last parts of a marathon. This was so frustrating because I had to walk to recover and stretch.

This obviously impacted my times and motivation levels since I didn't know why it was happening and what I could do to prevent it next time.

Yeah, that's gotta be soul-destroying! What other solutions did you try before you had a Sweat Test and tried Precision Fuel & Hydration electroyltes?

MC: I used to drink other sports drinks such as Aquarius and Gatorade. That worked better than just drinking water alone but, as it turns out, was not enough to get rid of the cramps.

So, you went for a Sweat Test and it turns out you lose ~1,556mg of sodium per litre of sweat. That puts you in the saltiest 15% or so of athletes.

Did you think you were a salty sweater before your Sweat Test confirmed it?

MC: To be honest I had not put two and two together that I was such a salty sweater before my test but, looking back, my family had always told me that my sweat was different from others and I quite often had headache after my trainings, along with the cramps late on in long runs...

Filip, is Marc the saltiest sweater you've seen come through the Belgium Sweat Test Center?

FR: With a 1,556mg/l sweat sodium concentration, Marc's maybe not the saltiest we've measured here, but he’s definitely up there! My wife actually has the saltiest sweat we've seen so far at 1,883mg of sodium per litre of sweat, but she barely sweats!

And in your experience, do most salty sweaters know they're salty before the test confirms it?

FR: I'd say that most of the athletes I work with maybe don’t know how salty their sweat is, but they have a feeling that there's something 'wrong' with their hydration/nutrition plan that's stopping them from performing at their best...

So, Filip, other than knowing how salty your sweat is, how do you think the Sweat Test helps your athletes?

FR: Sodium preloading before events is very much overlooked. A lot of athletes are preloading with carbs but are not aware that this should be done with sodium as well. Discussing proactive hydration tactics during the Sweat Test appointment is new and an eye-opener for most of them.

Agreed! And can you talk us through the other work you did with Marc in the run up to his New York Marathon and the benefits of that?

FR: By combining a lactate threshold test with an Advanced Sweat Test we not only nailed down Marc's hydration plan but I could also provide him with a training plan to finally achieve his goal in New York.

Based on the lactate threshold results, I gave him a detailed race plan with split times on several markers during the race to make sure he’s didn't go off too fast for his ability. It worked very well!

Ok, talk us through your 3:27 marathon, how did the race go and when did you realise you were going to get a PB? What was your previous PB again?

MC: 2018 was a great year in terms of training, no injuries hit me and I managed to get in some good quality training.

My race in NYC was also carefully planned hydration and nutrition wise.

The day of the race the weather was perfect, I felt very good from the first moment and I knew that I could get a PB, yet I still was a bit cautious at the end.

My previous fastest time was 3:46, also in New York, I was very happy to beat that by 19 minutes!

Marc after running the New York marathon cramp free! Image Credit: Marc Casals©.

I'll bet! Fantastic result. So, what's coming up in 2019 for you Marc?

MC: My main objective is to complete the 6 major marathons by the end of 2020. The focus this year will be Berlin in September, with a test point in Luxembourg on the 1st of June.

Challenges are a very important part of my life, I think they keep you alive and kicking! I'm also thinking about a fulfilling a dream I've had since I was a kid which is climbing the Cho Oyu on the China/Nepal border (the World's 6th highest mountain), but this might by one for 2021...

Sounds like you've got a fun few years ahead of you Marc! Here's hoping your new hydration strategy helps you stay cramp-free during all those adventures! Thanks guys...

Want to know how much sodium you lose in your sweat? Find a Sweat Test Center near you!