“Cramp?… Oh, you must have just overdone it”. “You are not fit enough”. “You should drink more”. “Have you tried chilli, tonic, mustard?” I have heard so many suggestions over the years, but I keep on struggling with cramp. Until now. Hopefully, using H2Pro Hydrate from Precision Hydration will be a real breakthrough for me. 

I recently had a sweat test done at the University of Surrey Human Performance Institute. The results confirmed and explained a lot:

  • I have a high sweat rate – anyone who has ever cycled with me knows that my face and clothes are generally caked in a white layer of salt crystals ;-
  • I have a high sodium concentration per litre of sweat relative to the average athlete population.

Electrolytes, including sodium, can be quickly depleted when sweating heavily, especially when training or competing in hot conditions, for long durations or on back to back days. This is exactly the sort of thing I do and struggle through with cramp. The 3 hours of more-or-less continuous cramp during last year’s National 12-hour Time Trial Championships is a prime example.


A ‘one-size-fits-all’ approach doesn’t work when it comes to hydration. Sweat rates and sweat sodium concentrations can vary dramatically (up to 15x) between individuals. Staying on top of and understanding my individual sweat rate and sweat sodium concentration is key to staying ahead of my hydration needs. Once behind it becomes increasingly difficult to catch up. Especially during long training rides and 12-hour and 24-hour challenges in the heat…

The sweat test showed that, to optimise my performance, my body requires approximately 1,208 mg of sodium for every litre of sweat that I lose. Because I have a high sweat rate AND a high concentration of sodium in my sweat, I am more likely to suffer from cramp. This means any electrolyte I have used to date simply doesn’t touch the sides.scale


I generally drink a lot, but also know that I am a heavy sweater. Somehow, even during the longest races, I never need the toilet. Although I drink a lot, I have little awareness of how well different drinks hydrate.

I really enjoy High5 Zero Neutral because it doesn’t have any sweet flavour. I generally use 750 ml water bottles and at best drink 1 bottle per hour. But if I add one High5 Zero Neutral tablets to 750 ml of water, I only get 200 mg of sodium, arguably plus 56 mg of magnesium and 70 mg of potassium, but this is so far removed from my actual needs.

Other electrolytes I have used include OTE Sports Hydro Tabs, SiS Go Hydro and Nuun Active. Whilst rehydrating me more effectively than water alone, and may be sufficient for other athletes, they all provide too low a concentration of sodium (ranging from 360 to 700 mg per litre) for me.

As a main energy drink during my races I tend to drink either OTE Energy Drink Vanilla (I love the flavour) or Etixx Energy Load Red Fruits (when racing in colder weather). The OTE energy mix only gives me 360 mg per 500 ml serving and I would normally mix one sachet into a 750 ml bottle. Although tasty and gentle on the stomach, this diluted energy mix certainly wasn’t enough for me. The Etixx energy mix gives additional carbohydrates but only 5 mg (!?) per 500 ml serving.

In recent long races, I have started to top up with SaltStick capsules (providing 215 mg of sodium per capsule), but I generally only took them in emergency situations (i.e. the cramp had already struck).


I did not really know what to expect from the sweat test or how it would actually work. I thought I would need to do some exercise on a stationary bike or something, but it turns out that all that was required was just to sit in a chair for 15 minutes with some electrodes on my arm which stimulate a sweat response. A sweat sample was then collected from this path on my arm and analysed through dedicated … 20 minutes later I had the results.

Here’s a video showing how it’s done…


Based on the test I now have a personalised hydration and electrolyte strategy with advice on when, what and how much to drink before, during and after training and competitions so that I am best equipped to achieve my goals.

H2Pro Hydrate have developed multi-strength electrolyte tablets. The strongest product in the range, H2Pro Hydrate 1500 has up to 3.5 times more electrolytes than any other brands I used before.


Based on my sweat test, I now will start using the following strategy:

Pre-load with H2Pro 1500 (which adds 1500 mg of sodium per litre):

  • Drink 1 x H2Pro Hydrate 1500 with 500 ml of water 1-3 hours before starting exercise.
  • Finishing your drink 45-60 minutes before you begin will allow your body time to fully absorb what it needs and eliminate any excess.
  • Drink 1 x H2Pro Hydrate 1500 with 500 ml of water the night before very long or hot events as well, to ensure you really are fully topped up.

Here is Why.

In competition use H2Pro 1500:

• In cool conditions and/or when you’ll only be sweating lightly, drink up to 1 x H2Pro Hydrate 1500 tablet in 500 ml of water during each hour of activity.
• In warmer conditions and/or when you’ll be sweating more heavily, drink up to 1.5 x H2Pro Hydrate 1500 tablets in 750 ml of water during each hour of activity.
• In very hot/humid conditions and/or when you’ll be sweating a lot, you may find you need as much as 1 x H2Pro Hydrate 1500 tablet in 500 ml of water for every 30 minutes of activity.

Bear in mind that 1 litre per hour is approaching the maximum anyone can usually absorb when exercising hard, so it’s unlikely you’ll benefit from having much more than that to hand, unless previous experience tells you otherwise. Also remember that listening to your body is key in determining how much to drink.

In training use H2Pro 1000: Same guidelines as for competing with H2Pro 1500, just using a lower dosage of sodium.
For ultra distance events: Or when carrying enough pre-mixed H2Pro Hydrate is difficult, take 3 x SweatSalt capsules for every 500 ml of fluid picked up at aid stations (after your initial supply of pre-mixed H2Pro Hydrate 1500 has run out). It is recommended to take no more than 10 capsules in a day. However in extreme conditions, some athletes find it beneficial to exceed this number.
Background hydration H2Pro 250: For use in between training and racing session (e.g. when travelling or in the office).

In addition to electrolyte/fluid imbalance there are also other causes of cramp (e.g. I believe some of my cramp is nerve-related and may have some other tricks up my sleeve for that).

However, a more informed and personalised hydration strategy should be a major improvement to my haphazard approach of the past. So fingers crossed it works. I will update my blog in a few months time with how using H2Pro Hydrate has effected (or hopefully avoided) cramp in training and races. Stay tuned.









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