I am kind of a minimalist and have disdained these things. 6 weeks ago I got a full suspension mtn. bike and have been taking 1-1.5 hr. rides on it 4 - 5 days per week. It is great fun but riding full suspension on dirt trails with mud, loose gravel, and steep (usually short) uphills involves a lot higher work output than pavement riding on a road bike, even though I do 3-4 hr rides on the road bike. The dirt riding is great fun. Narrow trails with the trees within arms length give a feeling of speed even though actual speed is a lot less than on the road. Much more bike handling skill is needed and downhills can be as thrilling as you can handle. The problem is that I have not enjoyed the rides very much after 40-45 minutes. In fact they can involve real suffering. I hit the wall, usually about 3 switchbacks into the 'hill of death'.

In UT, during my big year 1 of retirement I experienced the same thing after 3-4 hrs. of skiing in deep snow. Usually I skied from lift opening and quit for lunch when I ran out of gas. I just attributed this to age and being out of shape. Near the end when 15" + of new powder was falling every day it was so good I just couldn't stop and was pushing that skip lunch & ski plan to a later & later hour, eventually going 9-4 without rest or food. This was _hard_ but I accepted it as part of the price of having fun. The same thing happens skinning. It is worse now than it was 10 yrs. ago. I wonder if the muscles ability to store glycogen decreases with age.

Today I decided to try one of those foil envelopes of energy gel just before my daily ride. Wow! What a difference. This is after a particularly hard ride yesterday when afterward I had felt about as drained as I've ever been. Today there was no letdown after 40 min., no problem on the 'hill of death', and I felt as good at the finish as at the start. Yesterday, and after those hard days of skiing in UT and earlier in VT, I always need a nap after the exercise before I would feel decent. Today I feel great, energized, and no need for a nap.

I had been wondering whether it was better to train oneself through suffering, or try to manage energy levels through use of the modern gels, electrolytes etc. Now this question has morphed into, "Why spend half my precious recreational hours suffering?"

This is amazing stuff!

Don't go over 300kcals/hour straight carbs.

Take extra fiber pills if you miss lunch.

When it's hot, make sure you have plain water as well as energy drink.

I think some moderate combination of useful techniques is generally best.

First and foremost, which probably goes without saying, nothing can replace conditioning in the form of riding. I am just starting to hit my mid season stride where ascents that seemed impossibly hard at the beginning of the season now seem relatively easy. I attribute this mostly to the number of hours spent on my bike.

Also, as comprex suggested, proper hydration with H20 is important before, during and after your ride.

Ironically, given that caffeine is a diuretic, I do love a good sugar free red bull on my car ride to the trail head. I find that this little boost goes a long way late in the ride.

I have to say I have never tried an energy gel or anything like that.

Don't know anything about energy drinks, gels, or electrolytes. I come from the stone age when we'd never think of drinking water during an 18 mile run for fear of stomach cramps. But I'm more of a couch potato than an athlete these days.

I have a 55 yr old friend who I used to outrun back in our youth. He still runs 50 and 100 mile races. He talks about electrolyte and hydration management as 40% of the battle during those events.

Wiki on electrolytes:
http://en.wikipedia.org/wiki/Electrolyte