Author Topic: Rehydration in Hot Weather on Audaxes.  (Read 4667 times)

Rehydration in Hot Weather on Audaxes.
« on: June 03, 2019, 05:32:31 pm »
After failing on Windsor Chester Windsor 600 over the weekend, due to hot weather and dehydration, it's time to review my hydration strategy / tactics.  I haven't used hydration electrolyte tablets for some years preferring plain water and salty snacks but as has has just been borne out, this isn't enough as temps soar.

So I'm thinking a combination of electrolyte tabs in water, salty snacks, and diorlyte sachets as backup. I would class myself as a heavy sweater of salt.

What are other Audax riders doing, how much are you drinking, how much electrolyte are you putting in your water (bottle size for context please)?  How much are you drinking at stops?  Seems strange to be asking after a few years of Audax but I clearly haven't cracked dealing with hotter weather.  Any other tips welcome.

I have three weeks before I attempt to finish off my PBP qualification resit exam. So have time to try a small set of some variations. 

hellymedic

  • Just do it!
Re: Rehydration in Hot Weather on Audaxes.
« Reply #1 on: June 03, 2019, 05:48:30 pm »
Don't forget external cooling!

Wetting your clothing does not use much water and can effectively chill you well. Washing off excess salt will improve the efficiecy of perspiration.

Enjoy ice lumps and ice-cream when available.

I don't know if you have a h*lm*t impairing heat loss from your head but this needs to be considered.

dubya

  • You can't stop the waves,but you can learn to surf
Re: Rehydration in Hot Weather on Audaxes.
« Reply #2 on: June 03, 2019, 05:48:55 pm »
Sorry to hear WCW didn't work out for you, this weekend was such a hike in temperature it was a surprise.

I believe that hydration tablets have been largely debunked.  Several studies have shown that you just need to drink water. However (there is always a however) the added flavouring in the electrolyte tablets has the effect that you drink more!

I find this has been true for me too, if I just have a water I do not drink as much as I do when I have a tablet in bidon.

I set my Garmin to auto lap every 5km. When I hear the little lap tune (between 11- 15 mins) I take a glug from the bottle.  Little and often is the best way.

S2L

Re: Rehydration in Hot Weather on Audaxes.
« Reply #3 on: June 03, 2019, 05:50:34 pm »
Thyroid OK?

Re: Rehydration in Hot Weather on Audaxes.
« Reply #4 on: June 03, 2019, 05:52:23 pm »
I don't know if you have a h*lm*t impairing heat loss from your head but this needs to be considered.

Nope don't have that problem, but could have soaked my cap in water had I thought some more. I prefer to keep the cap on in direct sun but will remove if clouded over and at night time.

Re: Rehydration in Hot Weather on Audaxes.
« Reply #5 on: June 03, 2019, 05:54:43 pm »
Thyroid OK?

You are going to have explain that one.  I'm on no medication, and no diagnosed illnesses. What would be the symptoms of a duff thyroid?  I presume symptoms (whatever they may be) would show up outside long hot rides?

marcusjb

  • Full of bon courage.
    • Occasional wittering
Re: Rehydration in Hot Weather on Audaxes.
« Reply #6 on: June 03, 2019, 06:01:05 pm »
I believe that hydration tablets have been largely debunked.  Several studies have shown that you just need to drink water. However (there is always a however) the added flavouring in the electrolyte tablets has the effect that you drink more!

I find this has been true for me too, if I just have a water I do not drink as much as I do when I have a tablet in bidon.

I will totally go with that - I know I drink more with tablets than without.

Phil - have you tried arm coolers and/or leg coolers?

Again, I am sure that there's a chunk of snake oil in marketing materials for them, but I have found arm coolers very good when touring etc. in hot climates.

Whilst obviously not dealing with 40 degree plus etc., you react poorly to the heat, so maybe look at what RAAM riders etc. use in the desert sections?
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

zigzag

  • unfuckwithable
Re: Rehydration in Hot Weather on Audaxes.
« Reply #7 on: June 03, 2019, 06:11:59 pm »
i've been out on saturday, it was quite warm (28-29?) but movement from riding was enough to cool me down and not sweat. one doctor i spoke to advised to avoid sweating if possible as this is an "emergency" response to get the temperature down; it then takes more time and effort for the body to get back into it's normal state and restore the balance of minerals. i only use electrolytes if i'm sweating, which i did while riding in 30-40+ degrees, usually one tablet per bottle and one bottle an hour (on saturday - i only had one 0.7l bottle for 175km and did not feel too dehydrated). i have my garmin set up to alert me to drink every 20min.
wishing you good luck on your qualifiers!

Re: Rehydration in Hot Weather on Audaxes.
« Reply #8 on: June 03, 2019, 06:20:46 pm »
(on saturday - i only had one 0.7l bottle for 175km and did not feel too dehydrated).

Me too. Did 200k in slightly cooler conditions and rain for the final 40k helped but I find drinking more than that makes me pee so much that I have to stop every 5 - 10k.

If it gets really hot I try to soak my cap to keep me cool.
Hear all, see all, say nowt

S2L

Re: Rehydration in Hot Weather on Audaxes.
« Reply #9 on: June 03, 2019, 06:23:19 pm »
Thyroid OK?

You are going to have explain that one.  I'm on no medication, and no diagnosed illnesses. What would be the symptoms of a duff thyroid?  I presume symptoms (whatever they may be) would show up outside long hot rides?
Not duff, but hyper active
Check the symptoms for hyper-thyroidism and see how many boxes you tick...

Re: Rehydration in Hot Weather on Audaxes.
« Reply #10 on: June 03, 2019, 06:39:52 pm »
Thyroid OK?

You are going to have explain that one.  I'm on no medication, and no diagnosed illnesses. What would be the symptoms of a duff thyroid?  I presume symptoms (whatever they may be) would show up outside long hot rides?
Not duff, but hyper active
Check the symptoms for hyper-thyroidism and see how many boxes you tick...

None of the symptoms listed on Wikipedia

Re: Rehydration in Hot Weather on Audaxes.
« Reply #11 on: June 03, 2019, 06:51:56 pm »
I've always just used water with soft drinks at controls. Including when I did meridian hills perm in weather better than forecast when I drank 7 litres and didn't pee at all. What symptoms make you think you need electrolyte tablets?
   Eddington  87 miles

Re: Rehydration in Hot Weather on Audaxes.
« Reply #12 on: June 03, 2019, 06:55:38 pm »
Looking up heat exhaustion I had most of the symptoms


  • profuse sweating
  • weakness
  • nausea
  • vomiting
  • headache
  • lightheadedness
  • muscle cramps

So reasonably happy that's what it was.

Treatment seems to includes recognizing the symptoms, stopping the activity, and moving to a cooler environment. Rehydration with water or a sports drink is the cornerstone of treatment for heat exhaustion. So seems more water, and ways of keeping cooler , and stopping to cool down when necessary.

So if not hydration tabs how much water are people drinking? Is salt loss through sweat really a non issue?

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Rehydration in Hot Weather on Audaxes.
« Reply #13 on: June 03, 2019, 06:56:28 pm »
you can get your sweat analysed. Normally I shy away from such "snake oil", but the science seems pretty convincing, and I don't think it costs very much.

Look at rider's backs on a hot day - some have amazing white patterns on their back, yet some no mark. There is quite a difference.

I'm currently a great believer in electrolyte tablets. The science convinces me (so far!), and my sunstroke symptoms have reduced *massively* since I started using them, despite growing up surrounded by the "keep drinking!" ethos.

Oh and don't forget acclimitization - for many, this was our first hot long ride of the year. The body makes miraculous adjustments as the summer progresses, and magically events like PBP (i.e. late August, or later) become quite survivable.


Good luck!
Has never ridden RAAM
---------
No.11  Because of the great host of those who dislike the least appearance of "swank " when they travel the roads and lanes. - From Kuklos' 39 Articles

LittleWheelsandBig

  • Whimsy Rider
Re: Rehydration in Hot Weather on Audaxes.
« Reply #14 on: June 03, 2019, 06:56:52 pm »
I find ice creams and chilled drinks are worthwhile for lowering body temperature when riding in hot weather. Lukewarm water from my bidon, not so much. It worked well when riding in Oz and the Italians did it too when we rode Mille Miglia.

Given the amount I sweat even in cool weather and the visible salt-stains in hot weather, one of my two bidons often has something salty in it.
Wheel meet again, don't know where, don't know when...

Re: Rehydration in Hot Weather on Audaxes.
« Reply #15 on: June 03, 2019, 07:00:23 pm »
Being enclosed with limited through flow when the heat and humidity strike I sweat, I mean it runs off, if I didn't have a drain hole in the seat I would be sitting in a puddle. I normally drink about 1.5l per 100k when it is hot (little and often), this with tablets at minimum dosage, but at stops I drink another 0.5 - 1 litres, often cold milk. I find it physically hard to drink more and the longer the ride, the less I feel like drinking, as a result I'm always dehydrated to some extent which may take a day to rectify.

Sorry to hear about problems on the 600!

ETA, don't forget solar radiation, wear light colours not dark.

Re: Rehydration in Hot Weather on Audaxes.
« Reply #16 on: June 03, 2019, 07:13:23 pm »
I've always just used water with soft drinks at controls. Including when I did meridian hills perm in weather better than forecast when I drank 7 litres and didn't pee at all. What symptoms make you think you need electrolyte tablets?

Mostly the amount of dried salt on my skin and face, hat, and jersey plus the fatigue and muscle cramps. Maybe it's not the cause but there does seem to be a lot of salt. So I'm assuming the salt is the issue rather than liquids in general. But others posts are implying maybe I just need to drink a lot more and find ways of staying cooler and stopping to cool down again as necessary.

Here's the cap I was wearing till the sun went down. With the white all being sweated out salt.


Re: Rehydration in Hot Weather on Audaxes.
« Reply #17 on: June 03, 2019, 07:15:18 pm »
For long efforts in warmer conditions, hydration is obviously necessary but easy to concentrate on that when keeping one's body core cool is proportionately more important. In such conditions, people are more likely to go down with heat injury than because of dehydration. The cooling effect of cycling speed means this is more markedly the case for runners.
I offer this anecdote (which has influenced my opinion on this). The Three Peaks Yacht race (starts 15 June this year, from Barmouth (TINAT note)) takes in Snowdon (normally at night), Scafell Pike (often by day) and then a day plus later, Ben Nevis. The Scafell Pike leg is/was the longest: from the coast at Ravenglass (port changed nowadays) to Wasdale Head (20km); up and down (10km + 900m); back to boat. Three plus hours done in the middle of a hot June day, well hydrated, heading back with 10 miles to go at a brisk but steady pace (90 minute half marathon pace (with rucsacs)) my heart rate started to rise markedly (to above 180bpm), with no associated increase in pace and no self-perceived increase in effort/exertion. So the next time we reached our support, water went not down my throat but over my hat/head, shoulders down my back and front and on my legs. My HR dropped immediately back to 'normal' 160bpm (say). There is an inclination not to 'waste' water: it's needed for drinking. It's needed for body cooling too.
So my advice is (as @Hellymedic says): regular 'external' cooling and don't be concerned, any more than normal, with additional hydration: drink to thirst. This means keeping at least one bottle for plain water, whatever potions/tablets/powders you care to add to the other.
In a previous 'life' the Institute of Naval Medicine led some careful research into what liquids were best for maintaining proper hydration over a hard endeavour of 8 hours (across Dartmoor), in addition to eating ordinary food, a banana or 5 and a pasty (salted). The conclusion was:  . . . . . water.
Phil W said "Rehydration with water or a sports drink is the cornerstone of treatment for heat exhaustion."
I can find where you've quoted this from but am surprised at this. The 'cornerstone' of treatment (indeed ideally for prevention) for heat exhaustion must be body cooling.
To quote another site (on treatment):
"Anyone who suspects that they have heat exhaustion should immediately take steps to cool down. These can include:
    moving to a shady location
    removing one or more articles of clothing
    resting out of the sun
    turning on a fan or the air conditioning
    running cool water over the skin or applying cool, wet towels to the body
    drinking fluids such as water and sports drinks"
Shade, strip, fan, soak, and only then, drink.
If you have pint of water, most of it needs to go over the patient/victim, not down their throat.

bludger

  • Randonneur and bargain hunter
Re: Rehydration in Hot Weather on Audaxes.
« Reply #18 on: June 03, 2019, 07:28:18 pm »
Yes quite right heat exhaustion can't be 'drank away' unfortunately the squaddies doing the fan dance thought they could just suffer through it with enough to drink which led to their deaths.

I've only done one mega hot Audax which was the Locked and Boulted populaire in 2018. It peaked 31° at noon - I saw many people stopped and sheltering under trees as it was so hot.

In the last 10 km or so in Marlow I ran out of water and thought (being a local at the time) that I could just crunch on instead of stopping at a pub to refill. This was my worst cycling decision ever, and I spent an hour at the Arrivée drinking sugary drinks, sat down under a paradol with a soaked bandana mumbling incoherently with a headache.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD


Re: Rehydration in Hot Weather on Audaxes.
« Reply #19 on: June 03, 2019, 07:32:07 pm »
Not wanting to piss on your cornflakes, but it's possible this doesn't have a solution.

You clearly sweat profusely when hot, and dump all your electrolytes all in one go, which causes a cascade of symptoms from which there is no return - while you're still trying to carry on doing the very thing that started it all. It's not like this is the first time this has happened, is it?

I can ride in heat without too much trouble, provided the route is moderate, relative to my current fitness - assuming I can rest often and moderate my effort. These are not necessarily things you can do on a timed event when you're being chased by a time-limit.

There's a finite rate at which you can absorb water and electrolytes; if your physiology is such that it dumps your water and salts faster than you can assimilate intake, then your performance in hot weather is always going to be limited.

Here's hoping you can find a solution, or at least a compromise that can just about keep you going when it's hot. Not everyone can - some folks just have to hide when the mercury climbs.

Did you perhaps ride too hard in the run-up to onset of symptoms? It's easily done - I know!

simonp

  • Omnomnomnipotent.
Re: Rehydration in Hot Weather on Audaxes.
« Reply #20 on: June 03, 2019, 07:37:11 pm »
I reckon I was getting that way on the final day of LEL 2013 which was one of the hottest days of the year if not the hottest. It was resolved by sitting under a tree eating a magnum and the sun setting and pouring water over my head.

You’ll find heat acclimatisation helps. I trained indoors Saturday and Sunday this weekend and ended up drenched in sweat. Even on Saturday when it was an easy zone 2 spin. You can simulate hot conditions by keeping the window closed and turn the fan down or even off.

bludger

  • Randonneur and bargain hunter
Re: Rehydration in Hot Weather on Audaxes.
« Reply #21 on: June 03, 2019, 07:39:43 pm »
How about using long sleeve close-fitting technical clothes? E.g. the coolmax leg and arm warmers (seems counterintuitive I know...).
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD


hellymedic

  • Just do it!
Re: Rehydration in Hot Weather on Audaxes.
« Reply #22 on: June 03, 2019, 07:43:35 pm »
I did some very hot rides back in the day, without issues.

I really think much of the battle is dealing with excess heat before it creates issues with the body attempting to compensate with sweating. A wet flannel can cool you quickly and cheaply.

Sun gloop will impair your sweating.

Ice/Ice cream and slush drinks are good when available.

You will drink more if your drink has some flavour. I liked diet squash and half-strength fruit juice. Full strength fruit juice is hypertonic, as is full sugar cola. This means the body needs to pass water into the gut to be absorbed, which is sub-optimal.

If you are eating savoury food in normal amounts, there will be enough salt here, otherwise you might consider electrolyte drinks.

I have not seen much Isostar/Gatorade recently. Have they disappeared? I think various forms of Lucozade Sport are still available. Avoid anything that's more than 5% sugar.

Re: Rehydration in Hot Weather on Audaxes.
« Reply #23 on: June 03, 2019, 07:50:20 pm »
My solutions, as required, are minimal clothing – single layer with full-zip jersey, regular drinking, and the occasional pub-stop for orange & lemonade with crisps (or similar salted comestibles). 

Re: Rehydration in Hot Weather on Audaxes.
« Reply #24 on: June 03, 2019, 08:42:34 pm »
How about using long sleeve close-fitting technical clothes? E.g. the coolmax leg and arm warmers (seems counterintuitive I know...).

I think there's something to be said for this. I was reading that once there is too much sweat on the skin it's not able to evaporate and cool you. So what does the body do in response, produce more sweat, which doesn't evaporate. The wicking fabrics, one trademark you mention above, can keep you cool by wicking enough sweat away that the remaining sweat on the skin is able to evaporate , cool you, and stop or slow yet more sweat.  I wear lightweight merino tops on the recumbent and I find I sweat much less and feel drier than cycling tops. Maybe it's time to drop cycling tops and just wear lighter weight cooler merino stuff if hot weather is forecast.  Bib tights when upright don't help with all the extra material. It's not as if I don't have storage solutions otter than three pockets of a jersey on an Audax. The arm coolers Marcus mentions may also work on a similar principle.