I still have a couple of half marathons and a marathon on the horizon, but I ponied up for entries to two 1 mile and one 1500m races.
It has been probably 22 years since my last foray into the mile, so I am expecting comedy.
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Ouch! At least, the pain will end quickly 
I think most of the pain will be in the sets of 400s I will hopefully be trying to run to prepare.
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I was doing 400s on Monday. After the last one I just sat on a concrete step whilst I waited for everything to subside. All that lactate in your body is quite the feeling isn’t it?
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I did my first duathlon… they’re fun!
The one I did was a small event - probably 30-40 people? and was “sprint” distance 5km run - 21km bike - 2.5km run.
I need to practice running off the bike - legs were in bits! I think I finished 3rd overall (results not yet published). I’d say I was around 7th after the first run, up to second after the bike and one guy past me on the last run.
I think the guy who finished second took about 1:30 out of me on the last run in the end - which is shameful since it was only 2.5km 
I over achieved on the bike leg because I only saw 3 other people using TT bikes and it was a route that suited a TT bike. Although I did see on strava afterwards that a few people went round in groups of 2-3. I thought it was a non-drafting event but I don’t think it would have changed how I raced it.
TL;DR - I enjoyed it - would do again 
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Running fuel question.
Help with maths please?
Let’s say I burn out at 24km, regardless of pacing for reference between 5:40 and 6:40/km. so about 2h20 into an easy run or race.
Assuming I’m at the bottom end of physiology carrying glycogen for 1800kJ, would indicate I’m burning about 800kJ an hour.
So to keep going I’ll need fuel at about 800kJ an hour?
800/17= 45g carbs/hr
…so two gels and hour should keep me going?
Not sure I follow the question, but 800kj an hour at that pace seems like a bit of an overestimate unless you’re a pretty big guy.
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I would look at this differently, and in a simpler way.
Go for a run. See how many calories you burned. Whatever watch/app you use will tell you that. Assume you’d like to replace 50% of those calories on an easy run, or 75% in a race if you can absorb that much. Then 4 calories = 1g carbs. Start fueling with that from the start of the run.
You might find that you simply can’t absorb that much in carbs without GI distress, but most people will be fine (and you can increase your gut tolerance easily with practice). For example, I’m 240 lbs and raced a half-marathon at 622 cals/hr. Fueled with 90g/hr carbs from the beginning, arrived at the finish line destroyed by the distance but with plenty of energy and in a great mood (ergo, fueled well). It’s that easy. Modify to your personal needs.
[Nota bene: I ran the half in 3.15 hours, I’m still really slow. No doubt slimmer-but-faster folks can burn more calories per hour than I, but the theory and thinking is the same.]
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Thanks, already tried that way and know it. Trying something different.
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You’re burning 800kJs or 800 calories per hour? 1 calorie (kcal) equals 4.2 kJs. I think that’s your issue. 1g of carbs supplies 17kJs or 4 calories. I’m guessing you’re burning 800cals/hr which would be 200g of carbs to replace that completely… aka GI issues.
@BenB my maths says:
200g carbs would be 200*17 kJs
Ah I think I get your point, check this out:
Essentially they are equivalent for this discussion
This has always confused me, so I don’t want to say something wrong, so I’ll try to keep it brief and not confuse myself and everyone who reads this. From Wikipedia:
The energy contents of a given mass of food is usually expressed in the metric (SI) unit of energy, the joule (J), and its multiple the kilojoule (kJ); or in the traditional unit of heat energy, the calorie (cal). In nutritional contexts, the latter is often (especially in US) the “large” variant of the unit, also written “Calorie” (with symbol Cal, both with capital “C”) or “kilocalorie” (kcal), and equivalent to 4184 J or 4.184 kJ.[3] Thus, for example, fats and ethanol have the greatest amount of food energy per unit mass, 37 and 29 kJ/g (9 and 7 kcal/g), respectively. Proteins and most carbohydrates have about 17 kJ/g (4 kcal/g), though there are differences between different kinds. For example, the values for glucose, sucrose, and starch are 15.57, 16.48 and 17.48 kilojoules per gram (3.72, 3.94 and 4.18 kcal/g) respectively.
TLDR: there is a difference between kcal, calorie, Calorie, and kJ. I think that’s where the confusion is coming from.
I don’t think @JoeX is confused at all. A calorie is roughly equivalent to 4 joules. However, the body is roughly 25% efficient at consuming energy, so it takes burning 4 calories to create those 4 joules of actual work (edited to correct initial typo). For practical purposes in exercise or work done, one calorie burned by the body achieves roughly one joule of work. For all practical, real-world, daily purposes, calories and joules (or Calories, which are really kilocalories, and kilojoules) are equivalent.
His question is entirely different:
He’s starting out by describing the scenario as he understands it: based on the idea that he runs out of energy after 2:20 of easy running, and based on the estimate that his body carries 1800 KJ worth of glycogen reserves, he’s calculating that his net glycogen consumption rate is roughly 800 KJ per hour. This is the part that contains all the real science, and this is where he can really be right or wrong. What matters is whether his REAL net hourly consumption rate for glycogen is 800, or 600, or some other number.
Then, he’s trying to figure out fueling solutions based on that net glycogen consumption rate. That’ll be the easy part. The real meat of the issue is the calculations and estimates in the paragraph above. The units used to describe it are not important due to that 1:1 rough equivalence.
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My initial plan was to switch to cycling focus but have spent most of my time just dabbling in any/all things just too keep active; strength, rowing, hiking, kayaking… It’s been quite nice but now starting to feel the itch to get back into routine.
My Fall/Winter plans are still tbd so I may just focus on shorter runs/workouts and hop into a few 5k/10k’s until I figure out plans for later this year. The shorter runs would allow me to mix in cycling too.
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Thanks for summarising to BenB.
So that maths lines up with around 800kJ for an hour running on my Garmin and on a calculator on the fellrnr site. That calculator also shows how much less energy is needed for ‘normal’ weight people, blimey.
I think that gives me confidence Im fuelling well enough with two 26g gels an hour.
The rest is training and health. And water. I lose a kilo in the first hour of any run.
Thanks for helping me think this through.
FWIW I’ve run two half marathons in 1h50, but fell apart in two marathons…5hrs which I didn’t fuel. If I do it again I’ll be “one of those guys” with a hydration jacket covered in gels
I weigh 86kg where a normal weight would be 65kg. I’m not weak, I’m not unfit, but my body fat is only going to increase if the last five years are anything to go by.
I trained up to do a 30km run last autumn but bailed on it didn’t run farther than 21km
OK, I guess I am misunderstanding things because that’s not how I interpret Wikipedia’s explanation:
“Calorie” (with symbol Cal, both with capital “C”) or “kilocalorie” (kcal), and equivalent to 4184 J or 4.184 kJ"
and:
“Many countries and health organizations have published recommendations for healthy levels of daily intake of food energy. For example, the United States government estimates 8,400 and 10,900 kJ (2,000 and 2,600 kcal) needed for women and men, respectively”
I believe JoeX is doing the conversion backwards (or twice?). 800kJ / (17kJ/g carb) = 45g carb to have a net zero energy loss. This is not true based on my understanding. 45g of carbs will be about 180calories, not 800.
~50g carb/hr may be enough to not bonk, but it’s not replacing 100% of what you’re burning.
I believe that’s what you’re saying, but I might be missing something.
Honestly, the TR article explains it all and has the same level of detail plus more than the wikipedia article.
I did read it and I believe I understand it, but I’m just worried that you think by eating 50g of carbs you’re replacing 100% of what you burn. You are not, and I don’t want you to bonk and think that you’re replacing everything you burn.
If that’s not the case, I apologize.