It depends on how much caffeine is in the coffee. An expresso will definitely have more caffeine than a normal cup of coffee. A cup of Starbucks coffee will have more caffeine than a cup of Foldgers. A cup of Dunkin Donuts coffee will have more caffeine than a cup of Starbucks. If you drink more coffee, you will feel more of the effects of caffeine.
And here are studies saying caffeine is a diuretic:
http://www.mckinley.uiuc.edu/health-.../caffeine.html
http://personalbestnutrition.com/cgi...num=1102385617 (shows both sides of the dehydration issue)
http://www.vanderbilt.edu/AnS/psycho...ine_sports.htm
http://www.teahealth.co.uk/th/facts/7.htm
http://www.roble.net/marquis/caffeine (specifically addresses caffeine and cycling)
I could give more... but this is a good start.
Fact is, if you're using a pro-coffee website to find evidence of negative effects of caffeine, do you really think they're going to trot out reasearch that's negative towards the very product they are trying to promote?
I'm all for coffee. But I do think if you're going to consume it, you'd better follow through with drinking enough coffee to counteract the amount of water you drink. I think a lot of the studies out there may err in that the majority of people do not drink enough water everyday that they should be consuming. Then they enter a study that requires them to drink more water, and suddenly, they're in the toliet all day, then studies conclude that people who drink 80 oz of water vs. 80 oz of coffee are in the toliet the same amount, so coffee just CAN'T be dehydrating, since water produces the same result. But the error is that when someone does suddenly increase the amount of water they drink, they are going to initially end up in the toliet a lot until their body becomes more efficient at utilizing water. I started drinking a gallon of water everyday, and initially, I was in the bathroom like every 15- 20 minutes. It was a drag. But as I became more used to drinking that much water, I was in the toliet a lot less. Now, it's like once an hour or so. But then again, if I drink more coffee (I usually make a pot of about 5- 6 cups of coffee with my coffee beans I brought back from Italy and Switzerland, so it's unroasted, which gives me more caffeine), I'm back in the bathroom every 12- 20 minutes. So I don't drink coffee every single day. Only when I have the withdrawals... lol!!!
You'd have to give a stronger example of "fitness" magazines other than "Bicycling", which is not considered even close to a fitness magazine in the fitness community (check with ACE, AFAA, ISSA, and NCSF for real fitness magazines. They'll have the serious research on what factors affect fitness.
Koffee