Headache after workout (not dehydration ?)

Hi all,

Joined Zwift three weeks ago and I enjoy this very much, did some grouprides and 2 really hard races. My setup is a Wahoo Kickr combined with 2 fans in a large cool room.

One thing that is a big turnoff is that in 75% of the times I have a headache the day after working out. This will last the entire morning, feels like a hangover. I do sweat a lot during workout and I drink 2 0,75 liter bottles filled with non-sugar electrolytes for a 75 minute workout. After the workout I drink some herbal tea. During the year I ride a lot, so I don’t think it is the posture on the bike.

Does anybody recognize this and has some tips to overcome this ? Very much appreciated.

Eat a banana. Potassium needed.

It could still be dehydration, just because you are drinking 1.5 liters doesn’t mean this is enough

But as Kevin points out it could be a lack of potassium

Many Zwifters have the screen too low or too high. Maybe you are tilting your head and are using muscles or pinching nerves you are not used to?


If we assume that it’s not dehydration, maybe it’s your position? Not sure what your setup is, but I had issues with headaches until I realized that the TV was placed too high and the angle of my neck caused the pain.

Gonna try that

Thx, I will to drink even more, just to try at least

The TV is a little bit lower that my bike, so it resembles road position for my head (I look down a little). I will try to put a little higher. (lower would be really unnatural)

1 Like

having suffered something similar, I have recently noticed that my headaches have gone.
It early days at the moment (3 Weeks) but I have recently changed my smart trainer for rollers. Along with that change I also noticed that I haven’t had any headaches recently. My conclusion, (rightly or wrongly) is that I am riding more relaxed or the movement whilst riding rollers has stopped me being fixed in one rigid/tense position. (My headache I think would start from my neck but I was also thinking about dehydration)
Not totally sure, but definitely a real difference. I’m not saying change to rollers but trying to shake out/reduce any tension may help.

CO2 build-up in the room?

I weighed myself before and after a 2h session and lost 900g even if I drank 1,4L. I guess that flushes out a lot of salt and other stuff, too

Consider having a blood test with your doctor. I wouldn’t rule out you have a Vitamin D deficiency.



I second getting a blood test and make sure you don’t have a magnesium deficiency. I sweat profusely during rides. I drink 5 cups of water during and immediately after an hour ride. I then drink another 2 cups with a meal.

Most of the electrolytes have been mentioned as potential culprits… except sodium. It’s not uncommon for some cyclists to lose up to 2,000mg of sodium per liter of sweat.
The average person’s sweat contains only 150mg of potassium per liter. Clinical evaluation of these electrolyte swings is critical if you’re serious about avoiding such dangerous deficiencies.


Great article. I have kidney disease and I’m already on a low sodium diet. As someone who sweats profusely while exercising I think I’ll start adding more sodium to my fluids when I ride. This could definitely explain the mild headaches I get on occasion after a long ride. Maybe I’ll also test my sweat to see how much sodium I’m actually losing.


Room is big enough and I ride with windows open.

Hi, thanks for you reaction. It could be posture related, i noticed that the bike is offcourse way more fixed than on the road (I also feel this in my ass, saddle pain). By I guess my general posture is also way more fixed than on the road. Gonna try to change position more often

I do use electrolyte tables in my 2 bidons. My expection is that that would be sufficient. But the amount of sweat (a lot !) could indeed a culprit

1 Like

So this is in the tables (I use 1 in each bidon):

  • Energie0 kcal
  • Kalium/potassium 75 mg
  • Chloride/Chlorid 100 mg
  • Calcium 75 mg
  • Magnesium 50 mg
  • Natrium/Sodium 150 mg

Indeed… not very much sodium, eh? See my note above.