I've anecdotally noticed it, that I hit higher heart rates post the coffee stop. Today for example - 55km first half, my Strava says 121bpm average with 149max (my max max is only about 165 now)
The second half, of about 48km average was 132 with max of 156.
I don't feel that I was consciously going any harder, average speeds were about the same (0.3mph different). I had an americano at the stop, equally I had an aeropress before leaving home so while the coffee is the obvious suspect I'm not sure.
Anecdotally - if I go to Box Hill, I'll frequently get a higher heart rate after coffee on the drag up to Smith and Western than I did on the climb itself. Yes, I should hit the climb harder!
Caffeine?
Pretty sure average heart rate goes up as you get more tired (at least I've noticed mine does). So that combined with more caffeine would probably do it.
Everything is harder work with café legs?
Dehydration + caffeine. Both increase your heart rate considerably.
but, as I said in the OP, I've had a similar coffee before leaving home so while there is a second one 2.5 hours later is that really any different (what's the 1/2 life of the coffee effect?)
Subconscious anxiety at the cumulative laxative effects of two coffees and a few hours vigorous exercise?
I was told that caffeine can increase resting heart rate (if you drink a lot) but not when exercising, as that's still governed mainly by how much CO2 you have to shift.
It might be that you ate something and that increased your heart rate.
caffeine stimulates the release of adrenaline which makes your heart beat faster.
That's what the first coffee's for, it's like a single shot picolax. That and the nerve in my collarbone (you know, the one that triggers as soon as the strap of your bibshorts goes over it)
caffeine stimulates the release of adrenaline which makes your heart beat faster.
yes, but I have a similar coffee dose before leaving the house on the first half. Why does only the second one trigger the elevation.
Cardiac drift and a bit of dehydration. If you keep yourself properly hydrated you should be able to train yourself to be less fatigued in the second half of the training session. Your heart rate will still rise as you fatigue but not excessively. The guys who are strong at the end of a long ride are the ones who can still perform close to their normal level after three/four hours. This is also known as being well conditioned.
So first thing I’d do is ensure you are hydrating enough and fuelling enough. Once that is sorted you just need to work on your conditioning to ensure you are more fatigue resistant.
Caffeine will raise heart rate. Peak concentrations are achieved about 40 minutes after consumption. Expect 5bpm rise in peak for a decent dose (50-150mg).
Caffeine also has a six hour half life. So if you stop after two hours, you won’t have metabolised your first dose to any extent, but are adding a second rise.
It’s the same with alcohol, except the dose is vastly higher and units are removed at about one per hour. Drink two an hour and you’ll accumulate.
Subconscious anxiety at the cumulative laxative effects of two coffees and a few hours vigorous exercise?
compounded with the fear that sweaty arse crack and farting leaves you genuinely unsure if you have shat yourself or not.
if I go to Box Hill, I’ll frequently get a higher heart rate after
any red head in black leather in the vicinity?
Or dangerous men?!
Headwind home?
Change in terrain? Ate some food with coffee break? Temperature different? Caffeine? Lots of variables.
I remember looking up how much caffeine I was consuming, one of the sources I looked at suggested you get a bigger caffeine dose from cafetierre due to the longer brew time versus an espresso based coffee, so I suspect that applies to the aeropress too as it's a similar grind and steeps/brews for similar period.
Probably the easiest way to prove it's the coffee is to swap one, and then the other, out for a decaff version.
Have you tried without the coffee? Measure your drift without it then compare…
Everything is harder work with café legs?
Anecdotally this. Or possibly thegreatape's theory on bowel anxiety, especially if you are on some meds that affect digestion?
As I've got older I find I'm increasingly sensitive to caffeine, so it might be that
Because you’ve been stuck behind some tosser ordering seven different types of coffee and a few bayccinos when you just want a cup of tea.
Up to Smith and Western is always a bit slow if you’ve just stopped at the NT, that’s just the getting going again phase.
Which climb up BH, the road isn’t that difficult/ is doable taking it quite easy, one you get past the hairpin you can just spin to the top, the gravel track parallel a lot less so!
Pretty sure average heart rate goes up as you get more tired
Mine is the other way around, I can tell when I'm fatigued as my HR won't go into the Red anymore...
Eg Specialized 6 race, pairs event, on my 3rd outing I blew and you can see it clearly in the HR trace.
[url= https://live.staticflickr.com/216/478844134_8d825e25cc.jp g" target="_blank">https://live.staticflickr.com/216/478844134_8d825e25cc.jp g"/> [/img][/url][url= https://flic.kr/p/JjcFm ]Spesh 6 HR[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
Mine is the other way around, I can tell when I’m fatigued as my HR won’t go into the Red anymore…
Average heart rate for a constant zone 2 power ride increases over several hours even if your legs are fine. What you're describing is also true but a different phenomenon - during intense exercise your legs get tired and they can no longer function at a rate that demands the same oxygen/CO2 removal, so your HR doesn't go up as much. I observe both. Judging from the numbers on that graph, that's what you're seeing.
