Headache after intense training - Hydration/fueling? Analysis?

Hi All,

Male, 61kg, 173cm, 230FTP here. Over the last few years i have been getting headaches after intense rides and on the trainer. These get quite bad and tend to start after the ride and can progress into the next day. I was kinda used to them, but now that im actively trying to build fitness im pushing myself a lot more and these are becoming common.

For example yesterday i did Mills + 20min @160w.

  • Granola, blueberries and yoghurt for breakfast + creatine.
  • I had a lunch of 2 small burritos (mostly protein)
  • I had 1 nuun tablet with 700ml around 5pm.
  • Started riding around 6 pm. Had an energy gel (SIS) during warm-up.
  • Had a banana about 30 mins in. Also had about 700ml of water + nuun over the ride.
  • Finish ride about 7:30. 720 cal / 154 average / 159bpm average.
  • After ride had an apple with a couple table spoons of peanut butter.
  • About 2hrs (9:30pm) after ride had a light dinner of brisket and sandwich.
  • Got headache around 11pm. 3/10 pain.
  • two glasses of water… approx. 700ml.
  • Tried another nuun with 300ml of water.
  • Slept. Woke up around 8am with a headache. 6/10 pain.
  • Took ibuprofen around 9, headache gone by 10.

Note the nuun/gel does not have caffeine.

I had the same thing happen on Sunday on a bunch ride. A heavy push followed by a sprint about half-way through really cooked me. The ride home was fine, but as soon as i got back i was getting the headache and was pretty tired. For long tempo rides im absolutely fine, this seems to only happen when i’m absolutely at my limit (ie: im fighting to not bail on an interval or sprinting in a bunch ride).

What am i doing wrong? Is it hydration? Is it carbs? I’m burning 700cal but obviously not eating precisely that?

The gap between your fueling and when you ride seems like it may be a cause.
Have you tried ensuring that you are having a proper fueling meal 2-3hrs before you ride, rather than 6hrs? A gel just might not be enough to cut it.

Thanks Rondal.

I’ll get a list of suggestions and try one-by-one to narrow down the issues.

My Sunday bunch ride i had some granola before i rode and an energy bar about half way through.

Definitely could be an issue though. After nuun/sis tablets etc doubt the electrolytes is the issue.

How many calories are we talking here? I’m pregaming with 600 calories for a 1000cal ride, or 400cal in a bottle for a 800cal 1hr ride. Can you provide us some actual calorie consumption so that we can provide you some proper guidelines.

How many calories/carbs are you ingesting pre-ride and time duration before.
How many calories/carbs are you ingesting during the ride, and what is the source.

For my bunch ride (60km, 1300cal, 2hrs) i:

  • Had 200cal of granola and milk. About 300ml of water.
  • Had 1 bottle of SIS energy drink (700ml water + 140cal) over the ride.
  • 2 lattes with milk 50% into ride (200cal?)
  • 1 SIS energy bar about 75% into the ride (140cal)

(thanks Rondal)

Definitely not enough food before or during.

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Thanks Eric - Yes it seems like i’m not taking enough carbs? I’ll add that to the list for the next ride. I’ll aim to get 50% of the expected calorie expenditure prior to the ride and that again while im on the bike.


This is a good rule of thumb, and it means when you do get home or off the trainer you dont raid the fridge and eat everything in sight.

There was a good section on this in one of the recent podcasts by @ambermalika and @Pete

I eat and drink a lot less than you for a similar body size (58.5kg, 175cm & FTP of 260w), I don’t suffer from headaches. I’ll tend to carb load before a workout and do it closer to a meal.

Cool, yep I think I might just be a little more sensitive.

Today I tried an early morning ride (Darwin) after having a banana smoothie a couple of coffees and some maple syrup. After 25mins on the bike I was feeling ill so I guess eating before riding is not really my thing.

After a lay down for 30 mins I jumped on, finished the set and then followed it with Gendarme -5 cause I was feeling pretty good. I consumed 1000ml of water with SIS over that period and 1 nuun.

So it appears to be my nutrition rather than my hydration that is the problem.

I’ll continue testing with some instant oats and fruit bars in the morning (I think it was the milk that made me unwell).

Thanks TR community for your help,

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Thank goodness my sensitivity to anything ended about 25 years ago. When anything triggered a severe migraine. I had the docs worried and then it all stopped after a fit. Might be nothing to do with it but it was when I started wearing glasses but they are horrible in a sweaty workout :joy: