[Brian Bauer]

I have a bad habit of letting myself get dehydrated in races lasting 3-5hrs in the summer. At altitude, sweat loss evaporates immediately and therefore soaking wet clothes are not there as a reminder to hydrate.  I know these things, but I need to make a concerted effort to handle sweat loss/salt loss better.  I know from experience that I can lose 8lbs/4~ liters of fluid from sweat loss in a hot 3-5hr race…and thats loss after considering intake during the race.  I am basing this on A) feeling dehydrated at the finish B) the number of hours it takes and the number of liters of water I have to drink afterwards before reaching homeostasis .  a couple of. weeks ago I estimate that in 3.5 hours of racing I lost 6-8lbs of water weight while consuming only 1 liter of fluid in the race. yes it was a bad mistake and performance suffered.  I have a race in 10 days at altitude and last year it was very hot.  this year my race plan to be very intentional about drinking no less than than 1 liter ( 2, 500ml soft flasks) per hour.  I am hoping to get closer to 1.5L/hour, but 1L is the minimum . to deal with electrolytes , I have  Salt Stick sodium/potassium capsules. I have used them the past so I know I can tolerate them.  What I don’t know is how much sodium per hour to take.  I think the minimum would be 500mg of Sodium and 100mg of Potassium ( equals 2 capsules) per hour.  I feel like that might be a little light based on my sweat loss estimates.  without the benefit of a lab test, any idea to figure out sodium/potassium per hour for the race?

[jesse@evokeendurance.com]

Hey Brian,

Jesse Rich here, a coach and nutritionist for Evoke Endurance. Thanks for your question! Seeing that just 2% body weight lost in sweat can impair performance, hydration is critical to perform at your best. Looks like you’ve already done a sweat test more or less. I didn’t see super specific times though (i.e. 2 pounds lost per hour), getting more specific there could help you quite a bit. To do that, do what you likely did before which is to weight yourself in the morning on an empty stomach and naked, then go on a run for one hour in the temperature you think would most mimic your race, then towel yourself off of sweat and weigh again naked. You want to replace 100% of water lost.

When it comes to electrolytes, it is impossible to be as precise without a test. I recommend levelen.com. You can get your test there for $120. You might as well just hold off on the sweat rate test if you’re going to do this test because that’s part of it too. You’re right though in that 500mg of sodium is a pretty safe minimum for almost everyone, but it can be up to 1,000mg or more depending on the person. Getting tested is well worth the investment to not have to guess and hope for the best in my opinion. It might be tight to get it done before the race, but at least you can have the water dialed. By the way, you have to train to drink that much too. If you just drink one 500ml flask per hour in training for example, don’t expect your stomach to tolerate one liter per hour unless you’ve done it several times hour after hour in training.

I hope this helps! If you’d like me to review your test if you get it or have a consultation with me, feel free to email me at jesse@evokeendurance.com. Good luck!

[Brian Bauer]

thanks Jesse.  yesterday I did a 3hr mountain run at altitude in moderate heat. I drank 3 litres with no problem. it was not crazy hot so that was probably enough.  1.5L/hour if I am really sweating.   30k race this coming weekend at Jackson Hole.  forecast calls for 90 degrees in the valley, a little cooler up high…I raced the same race last year and it feels hot.  I should be able to tolerate 1.5L/hour of water no problem( 2 500ml soft flasks in the vest and chug an extra one at each aid station). so regarding sodium for the race, if 500mg is the minimum, is it better to take a little extra sodium? or be conservative ? eg 500mg vs 750mg per hour? thanks

[Brian Bauer]

ok so yesterday I raced 5hrs at altitude in the heat.  I drank about 6 liters, maybe 6.5.  I did not get dehydrated and still had running legs at the end. as for electrolytes : at hours 2 and 3, I took 500mg sodium + 2 Sportleg capsules( magnesium + lactate).  after a bit my belly got bloated. it was not uncomfortable exactly, but I figured it was too much sodium.  I did not take any more capsules during the race. my belly went back to normal.  I was also drinking 500ml Tailwind in addition to the 500ml of water every hour.  I think next race I will take only 500mg of sodium per hour.  I think tailwind might be 350mg, so 850 was too much.  as a side note, often in heat race my fingers get puffy.  I had no puffiness yesterday, so I was close to get hydration/electrolytes dialed

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