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I'm 173 cm with about 45 kg weight (underweight). In the same ride of 30 km with short but steep uphill and downhill, if I drink coffee I tend to feel better when riding, but about two hours after the ride I would feel weak and shaking. Note that I drink about 150 ml moccachino. I don't feel like this if I don't drink coffee. Is there an explanation to this? Am I maybe intolerance of coffee? Maybe I don't eat enough? Personally I don't really enjoy the taste of anything other than moccachino.

Rizki Hadiaturrasyid
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  • As a health question this would be off topic, but as a performance question it wouldn't. Do you measure your times? Perhaps you go faster after coffee and tire yourself out, because you feel better. There's some research on caffeine and exercise tolerance, and some people tolerate exercise on an empty stomach better (sugar in your drink probably doesn't count). What do you eat before the ride? Does this differ depending on whether you have coffee? – Chris H Jan 05 '18 at 12:03
  • Could you expand on what your normal caffeine intake is, and what you normally eat during these rides? – JohnP Jan 05 '18 at 19:13
  • Caffeine used to be on the banned substances list. But that would need more than one espresso, rather some 20. Caffeine speeds up the the metabolism of sugar. That is why I think that you are more likely to suffer from hypoglycaemia (low blood sugar) after a long ride without food and considering your low weight. Have a check-up from an MD. – Carel Jan 05 '18 at 19:30
  • @Carel - IIRC, it was removed in 2004 or 2005. – JohnP Jan 05 '18 at 19:36
  • @Carel do you have a source for that "speeds up the metabolism of sugar"? It's something I've long thought but never seen hard data. – Chris H Jan 05 '18 at 22:26
  • @ChrisH - These two studes would seem to indicate otherwise. Stuidy 1 - Study 2 – JohnP Jan 06 '18 at 00:52
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    It might help to get your weight up, till you are 'just underweight' rather than 45kg at 173, that is in the anorexia part of seriously underweight. With a very low weight your body will react much more strongly on exercise and the reactions on caffeine as it has no reserves at all to cushion the effects. Seek medical help if you can not get your weight up alone, it is a common enough problem. – Willeke Jan 06 '18 at 15:40
  • Yeah I know. I'm trying to eat as much as I could even though I don't feel like it. If I don't ride bikes and eat as much as I want, I'd stay at around 45-48 kg, and when I started cycling again after a few years hiatus, it used to go as low as 43 kg. – Rizki Hadiaturrasyid Jan 09 '18 at 15:05

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A recent documentary on the BBC in UK covered some aspects of ingesting caffeine prior to exercise. A written summary is here:

http://www.bbc.co.uk/programmes/articles/23hqLh1TYQqZdql7GkqQZ1L/which-types-of-exercise-benefit-from-caffeine

Without reviewing the science in detail, it basically suggests that for endurance type activities, caffeine blocks receptors in the body, leading the brain to "perceive" less pain and fatigue, allowing someone to exercise longer. The article states an optimum amount of caffeine to be 3mg per kilo of bodyweight (somewhere between 1 and 2 large cups of filter coffee for average man / woman). To experience the benefit you should drink the coffee approximately one hour before starting the activity, and the effect will last for "a few hours". If you regularly drink a lot of coffee (or take other sources of caffeine), it is likely the impact will be reduced.

Your experience may just be the effect of the coffee / caffeine wearing off, plus any lessened impact due to the amount of caffeine you ingest on a daily basis.

Of course, other factors may be causing your fatigue, but your question specifically asked about effects of coffee / caffeine.

Mike
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    The article under reports the amount of caffeine necessary, and studies are a bit mixed on whether abstaining increases the effects. – JohnP Jan 05 '18 at 19:18
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2 hours is about how long your body has glycogen stores for. So you're bonking because your body has used all the available glycogen.

The caffeine will be making fats easier to process instead of glycogen, theoretically leaving you with more "on-tap" at the end of your ride. But you are a scrawny wee twig and lacking in mass, so for you there is less fat available, and the bonk wall will be steep and and immediate, a figurative wall.

Your solution is to eat more while riding. Start with a gel every ~30 minutes and see how you feel at the 2 hour mark. Gels are basically easily-digested sugar slop with some flavour.

If you don't like gels, then try a square of chocolate. Break it up and freeze it overnight, and store it in a top tube bag or somewhere else not directly on your person. Chocolate is also a significant component of your drink, making it a good substitute that can go with you on the bike.

A moccachino is 2/3 cocoa and milk, with an espresso shot, topped with milk foam and dusted with powdered chocolate and optional chocolate syrup.

Criggie
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  • Gels can be expensive, so shop around. For brands, GU is great but spendy and has nice chocolate and espresso variants. SIS are fair priced but larger and I personally haven't found a flavour I like, and there are perfectly good cheap ones from High5/Wiggle. – Criggie Jan 05 '18 at 22:27
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    Other things to try (as some people really don't get on with gels and many others don't get on with only gels): energy drink powders; sweets (jelly babies are popular); bananas; dried fruit. – Chris H Jan 05 '18 at 22:52
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    I would have to find it again, but there was a study that suggested sucking on a sweet hard candy convinced the body it was getting more food, so it released more glycogen. I'll do some digging for that. – JohnP Jan 06 '18 at 00:56
  • @ChrisH I hate bananas on a bike. They get warm, and go brown/black quickly, and the smell remind me of beach picnics with my late grandparents. Personally I like gels, bliss balls, frozen chocolate, fruit bursts, and perhaps a moist muesli bar at normal mealtime. – Criggie Jan 06 '18 at 08:54
  • @rizki I mean no insult by the description of your body type. At 97 kilos, I'm envious :) – Criggie Jan 06 '18 at 08:54
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    I'm no fan of bananas either. It was all OK until I had to clean the remains of one off the inside of a pannier after lying the bike on it. But some people swear by them. My personal preference is a mix of gels, dried fruit/nuts and snack bars. – Chris H Jan 06 '18 at 09:09
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    You usually chose a greener banana for riding that you would chose for straight away eating, so that it doesn't go black and soft quickly. That's the trick. They are naturally wrapped, you can even eat half and keep the other half in your pocket without too much of a mess, and Id say they go easier on the stomach than man processed gels/bars, which can be bad for the belly in higher quantities – gaurwraith Jan 06 '18 at 22:38
  • A couple of things don't make sense to me here. 2 hours is about how long your body has glycogen stores for. So you're bonking The OP said "two hours after the ride," not "after two hours of riding." there is less fat available, and the bonk wall will be steep A typical human body has somewhere on the order of 10^5 kcals of energy stored in fat. This means that fat is an effectively unlimited store of energy for endurance sports. It's just that your body can't burn it as fast as it burns glycogen. The OP is undoubtedly on the low end, but there's no way he's simply out of fat energy. –  Jan 09 '18 at 20:20
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I suggest taking a break from caffeine before riding for 2 weeks to reset the body and see how you cope with your normal mileage

DB NYC
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