Dehydration during exercise
Discussion
I was going to post this in the running thread but thought I’d open it up to a wider audience.
I’ve started increasing my running distances and I’ve noticed that on my long runs over about 20km (1hr 50 ish) I’ve been feeling very dehydrated afterwards. Yesterday I ran 30km (3hrs) and felt so ill afterwards that I ended up going to bed at 8:30pm. This happens after about 50% of my long runs.
Symptoms are mainly headache (identical to a hangover) so I know it must be dehydration. I already know I’m a salty sweater. I still have headache today.
The day before my long runs I’ve been drinking 3L plain water and carb loading. The morning of the long run I get plenty of plain water and carbs. During the runs I take 1L of lucozade sport with me and drink it all, along with a protein bar during the run. After the run yesterday I drank 2.5L water with 2 Nuun Sport hydration tablets and also had another lucozade sport (500ml).
I still feel rough today (like I’ve drunk 10 pints of lager)
. I’m on my second hydration tablet and am just about coming round as I write this.
To cut a long story short this isn’t sustainable. It’s putting me off doing long runs. My run yesterday was in 0 degrees weather. I’d hate to see how I would be on a warm sunny day.
Any advice?
I’ve started increasing my running distances and I’ve noticed that on my long runs over about 20km (1hr 50 ish) I’ve been feeling very dehydrated afterwards. Yesterday I ran 30km (3hrs) and felt so ill afterwards that I ended up going to bed at 8:30pm. This happens after about 50% of my long runs.
Symptoms are mainly headache (identical to a hangover) so I know it must be dehydration. I already know I’m a salty sweater. I still have headache today.
The day before my long runs I’ve been drinking 3L plain water and carb loading. The morning of the long run I get plenty of plain water and carbs. During the runs I take 1L of lucozade sport with me and drink it all, along with a protein bar during the run. After the run yesterday I drank 2.5L water with 2 Nuun Sport hydration tablets and also had another lucozade sport (500ml).
I still feel rough today (like I’ve drunk 10 pints of lager)
. I’m on my second hydration tablet and am just about coming round as I write this. To cut a long story short this isn’t sustainable. It’s putting me off doing long runs. My run yesterday was in 0 degrees weather. I’d hate to see how I would be on a warm sunny day.
Any advice?
I'm a heavy sweater and use these - https://www.precisionhydration.com
You can also email them and ask them any questions.
You can also email them and ask them any questions.
Hi there. I'm a keen runner and have a few questions for you:
1) Are you drinking enough throughout the day?
2) Do you sweat much?
3) Have you tried weighing yourself immediately before and after a run?
4) Finally, how are you running? Are you pushing on every run? because that's not recommended. Virtually all sports scientists and coaches agree that most running should be at an easy, conversational pace (for me as a 43 year old regular runner this is around 135-145bpm heart rate). For example, I race a 10k at 3:40 to 3:50min per km, but my easy pace is a pedestrian 4:45-5:00min/km! To train your lactate threshold and VO2 Max for race speed you then do targeted sessions called tempo and intervals respectively, which are mostly easy running with bouts of running at speed. Runners only ever run at race pace for extended periods during races. The only exception to this is marathon runners, who occasionally do marathon pace runs, at most once a fortnight.
Everyone's different, but personally I don't take a drink if the run's shorter than about 70mins for an easy run, or less for a harder run. When I do take a drink, it's usually 0.5L to 1.0L, depending on how hot it is. I use this Camelbak: https://www.camelbak.co.uk/shop-c35/packs-c36/mult...
1) Are you drinking enough throughout the day?
2) Do you sweat much?
3) Have you tried weighing yourself immediately before and after a run?
4) Finally, how are you running? Are you pushing on every run? because that's not recommended. Virtually all sports scientists and coaches agree that most running should be at an easy, conversational pace (for me as a 43 year old regular runner this is around 135-145bpm heart rate). For example, I race a 10k at 3:40 to 3:50min per km, but my easy pace is a pedestrian 4:45-5:00min/km! To train your lactate threshold and VO2 Max for race speed you then do targeted sessions called tempo and intervals respectively, which are mostly easy running with bouts of running at speed. Runners only ever run at race pace for extended periods during races. The only exception to this is marathon runners, who occasionally do marathon pace runs, at most once a fortnight.
Everyone's different, but personally I don't take a drink if the run's shorter than about 70mins for an easy run, or less for a harder run. When I do take a drink, it's usually 0.5L to 1.0L, depending on how hot it is. I use this Camelbak: https://www.camelbak.co.uk/shop-c35/packs-c36/mult...
Edited by RobM77 on Thursday 31st December 15:38
Edited by RobM77 on Thursday 31st December 15:39
feef said:
It sounds like you're insufficiently hydrated day-to-day and your exercise is pushing you over the edge.
I'd agree with that. You could try a hydration vest for longer runs, but the answer is probably to hydrate better day to day and not just immediately before / after runs. Personally I'd ditch the Lucozade Sport as well - nasty, sticky, sugary stuff... but that's just me
Thanks everyone.
To answer some questions;
@Mazinbrum - I’ll look into these more at the weekend but on first glance they appear very similar to the Nuun tablets I use.
@feef/smn159 - I’m pretty well hydrated usually. Always drink at least 2L of water per day, but probably closer to 3L. I don’t drink much coffee (3 cups per week maybe). Most weeks don’t touch alcohol. Urine is usually a hydrated straw colour. Wake up most nights to pee (presumably due to amount of water I drink in day).
@RobM77 -
1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
To answer some questions;
@Mazinbrum - I’ll look into these more at the weekend but on first glance they appear very similar to the Nuun tablets I use.
@feef/smn159 - I’m pretty well hydrated usually. Always drink at least 2L of water per day, but probably closer to 3L. I don’t drink much coffee (3 cups per week maybe). Most weeks don’t touch alcohol. Urine is usually a hydrated straw colour. Wake up most nights to pee (presumably due to amount of water I drink in day).
@RobM77 -
1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
JapanRed said:
Thanks everyone.
To answer some questions;
@Mazinbrum - I’ll look into these more at the weekend but on first glance they appear very similar to the Nuun tablets I use.
@feef/smn159 - I’m pretty well hydrated usually. Always drink at least 2L of water per day, but probably closer to 3L. I don’t drink much coffee (3 cups per week maybe). Most weeks don’t touch alcohol. Urine is usually a hydrated straw colour. Wake up most nights to pee (presumably due to amount of water I drink in day).
@RobM77 -
1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
The thing that sticks out for me from that is that 50km a week isn't really enough to support a long run of 30k - your long runs should be 25-30% of your weekly mileage.To answer some questions;
@Mazinbrum - I’ll look into these more at the weekend but on first glance they appear very similar to the Nuun tablets I use.
@feef/smn159 - I’m pretty well hydrated usually. Always drink at least 2L of water per day, but probably closer to 3L. I don’t drink much coffee (3 cups per week maybe). Most weeks don’t touch alcohol. Urine is usually a hydrated straw colour. Wake up most nights to pee (presumably due to amount of water I drink in day).
@RobM77 -
1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
If you work more gradually to build up your weekly mileage you are likely to find the longer runs easier - it may be as simple as your current base fitness not being enough to support your longer runs.
JapanRed said:
@RobM77 -
1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
1) Ah, no, I didn't mean right before your run, I mean drinking throughout the day, from when you wake up till when you go to bed - are you drinking enough water? You need little and often. What colour is your pee?1) as above
2) Yes. I’ve always sweat quite a lot. Even get sweaty lifting weights in gym. Sweat loads when running even steady. My 5k PB is 23 mins so around 4:35 /km but even on a steady run (yesterday was 6:10 /km) my shoes and rest of clothes feel wet with sweat. I also have a strong saltiness to my skin after running suggesting I sweat salts more than most.
3) Never tried weighing myself but read about it so might try it next week after my long run.
4) 80% of my runs are what I would call a steady pace. Average HR yesterday was 156 (average on a fast 5km would be 175+). Tempo, VO2 max and hill sprints make up the other 20%. I’m currently running about 50km per week but it’s gradually increasing. Although I would call my long runs steady, they are very tough simply because up until 4-5 months ago I’d never run more than 20km. Yesterday’s 30km was very tough simply because my body isn’t used to it (I’m increasing distance by <10% per week).
Thanks for the heads up on camelbak, I’ve got a hydration vest with bladder already which is very good and can hold up to 2L at a time.
2) Fair enough - everyone does vary. Your race pace and easy pace do seem reasonably compatible, which is good. I'm guessing you do just naturally sweat a lot.
3) Have a go - you should lose a little weight on a run, but not too much.
4) I've never raced 5km, but I suspect I'd average the same as you: about 175+. My max is 185 and in a 10k I'm normally around 170, just above my LT of 167. Given our similarities there, 156 seems far too high for an easy run (I'm 135-145!). If you look online you'll see guidelines relating to % of your max heart rate and % of your HR range. 50km a week is fine, but if you look at all books and online resources, the typical long run is recommended at 20-30% of your weekly distance, so 20-30km is far too long for you!! 12-13km would be more appropriate as a long run for your weekly mileage. That combined with your effort level and it's no surprise you're getting dehydrated, and injury is a high possibility.
Edited by RobM77 on Thursday 31st December 17:32
Might be worthwhile taking electrolytes if you sweat a lot. https://amzn.to/3pHTbDF
In summary, I would suggest:
1) Drink more during the day, all throughout the day.
2) Wear less in winter so you don't get as hot.
3) Back off a bit on your easy runs. Don't let your form suffer, but try to run at a "run all day" type of pace; the sort of pace where you could easily hold a conversation.
4) Drop the long runs to 25% of weekly distance.
5) Lastly, I'd recommend some sort of camelbak or hydration vest if that's more your sort of thing. As Hoofy says above, look into electrolytes and sports drinks that offer this.
1) Drink more during the day, all throughout the day.
2) Wear less in winter so you don't get as hot.
3) Back off a bit on your easy runs. Don't let your form suffer, but try to run at a "run all day" type of pace; the sort of pace where you could easily hold a conversation.
4) Drop the long runs to 25% of weekly distance.
5) Lastly, I'd recommend some sort of camelbak or hydration vest if that's more your sort of thing. As Hoofy says above, look into electrolytes and sports drinks that offer this.
Check out Runalyze as well - I'm a big convert this year.
Your long runs suggest that you're training for a marathon, in which case it will work out your optimum time based on your current fitness level, but will also tell you the weekly mileage and long run that you need to achieve consistently in order to achieve it.
It will also tell you the paces to run for different workout types, again based on your current fitness levels.
Takes the guesswork out of it.
Oh, and it's also free with the option to donate if you like it (but with no compulsion to do so)
Your long runs suggest that you're training for a marathon, in which case it will work out your optimum time based on your current fitness level, but will also tell you the weekly mileage and long run that you need to achieve consistently in order to achieve it.
It will also tell you the paces to run for different workout types, again based on your current fitness levels.
Takes the guesswork out of it.
Oh, and it's also free with the option to donate if you like it (but with no compulsion to do so)
Thanks for the comments.
I’ve read that long runs should be no more than 25/30/50% of weekly mileage (differs depending on source) but this doesn’t account for nearly every marathon training plan not sticking to this “rule” which makes me wonder how necessary it is.
I am indeed training for a marathon. I’m following Hal Higdon which a few people have recommended. Most plans I’ve seen suggest 60-70km weekly mileage for a marathon which I’m building up to.
SMN159 - Thanks I’ve just signed up to RunAnalyze. Will check it out later today.
Still can’t understand why I’m getting dehydrated when I use a Camelback and already take electrolytes. Might just need to back off on the effort level.
Thanks everyone.
I’ve read that long runs should be no more than 25/30/50% of weekly mileage (differs depending on source) but this doesn’t account for nearly every marathon training plan not sticking to this “rule” which makes me wonder how necessary it is.
I am indeed training for a marathon. I’m following Hal Higdon which a few people have recommended. Most plans I’ve seen suggest 60-70km weekly mileage for a marathon which I’m building up to.
SMN159 - Thanks I’ve just signed up to RunAnalyze. Will check it out later today.
Still can’t understand why I’m getting dehydrated when I use a Camelback and already take electrolytes. Might just need to back off on the effort level.
Thanks everyone.
There’s a good summary somewhere online, but yes, recommendations for long runs vary from 25-30%. Jack Daniels also says to keep long runs to two hours. Time on your feet also presents injury risk, it’s not just distance alone.
The issue with the marathon is that you have to get long runs up to about 30km to stomach the 42km on race day. For most people this will be over 2 hours as well, or even 3! This is all no issue for people whom 30km is 25-30%, and they’ll be knocking out 30km long runs regularly (maybe close to two hours as well!); but for lower mileage runners, it means you’ll have to break that rule, but obviously with care!
If you’re training for a marathon, I’d recommend this book:
https://www.amazon.co.uk/dp/0736074600/ref=cm_sw_r...
I found it from recommendation from the online coaches I follow: Sage Canaday, Ben Parkes and others. Note that this book also recommends long runs are done at slightly quicker than easy pace, so you’ll need more to drink! Mind you, in this cold weather that won’t be too much - I still had a fair bit of my 500ml left after my two hour run today.
The issue with the marathon is that you have to get long runs up to about 30km to stomach the 42km on race day. For most people this will be over 2 hours as well, or even 3! This is all no issue for people whom 30km is 25-30%, and they’ll be knocking out 30km long runs regularly (maybe close to two hours as well!); but for lower mileage runners, it means you’ll have to break that rule, but obviously with care!
If you’re training for a marathon, I’d recommend this book:
https://www.amazon.co.uk/dp/0736074600/ref=cm_sw_r...
I found it from recommendation from the online coaches I follow: Sage Canaday, Ben Parkes and others. Note that this book also recommends long runs are done at slightly quicker than easy pace, so you’ll need more to drink! Mind you, in this cold weather that won’t be too much - I still had a fair bit of my 500ml left after my two hour run today.
Edited by RobM77 on Saturday 2nd January 17:55
I don't think hydration is as important as people make out. People get obsessed by it which is why you see people running with big bottles of water etc. Losing water is a consequence of training just as much as getting tired is - it is going to happen if you are doing it properly.
Personally I never take on any water if I run for an hour or less and I avoid carrying any water at all unless I am on the hills. If I do run for more than an hour then I will just plan a route that takes me past a place that I can buy a bottle of water. Quick 2min break while I down half and then just sip the rest over the next mile.
As discussed above the most important thing is to make sure you are properly hydrated before you run.
Personally I never take on any water if I run for an hour or less and I avoid carrying any water at all unless I am on the hills. If I do run for more than an hour then I will just plan a route that takes me past a place that I can buy a bottle of water. Quick 2min break while I down half and then just sip the rest over the next mile.
As discussed above the most important thing is to make sure you are properly hydrated before you run.
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