Hi,

Seeing that your race will be supplying Gu Gels I would suggest trying those as this will mean you can carry less on the day of the race. You may have to try a few varieties though before you find one that you like or doesn't upset your stomach. Some people like caffeine gels, my personal opinion is that if you are going to use caffeine it should be towards the end of the run.

As for Hydration, unless you get lucky, there is a lot of trial and error. Despite some of the scare stories regarding over hydration (hyponatremia) it is actually quite difficult to do as long as you are reasonably sensible so don't let it put you off drinking water.

As well as drinking water you should also drink electrolytes, the key to how much depends on you as an individual and the running conditions.

When I run long runs I also take something slightly more solid - a flapjack and break it into small pieces to eat around the half way mark.

Some people advocate conditioning your body to running with minimal carb supplementation, personally I don't think for your first marathon that's a good idea.

Once I start running over 10 miles I look to having a gel roughly every 6 miles or so.

Gels are only one part of the jigsaw tghough, ensuring that your diet is spot on 7 days a week is also important because if it's not, no amount of gels will get you through the longer long runs.

I'll reply from a different perspective than most of what you will hear.

My opinion, based on my personal experience over the last 9 years running is that, under most conditions, you don't need hydration or nutrition on a training run. I've done up to 22 miles without anything. The only exception is under extremely hot conditions, you will need water. If the temperatures are going to be over about 75°F, I'll start to think about carrying water with me. If you run early in the morning during summer, there are very few days that it becomes necessary to do this and then only on runs over 15 miles.

The human body is designed to use the fuel that it has stored. If you eat a proper runners diet, making sure you get your carbohydrates to build your glycogen stores, then you don't need to supplement that during a run. Part of the purpose of the long run is to train the body to efficiently use fat stores and glycogen to fuel the muscles. When you add fuel from an outside source, you are compromising the purpose of the run.

We are also very efficient at maintaining an electrolyte balance as the body becomes dehydrated. The body maintains a constant state of homeostasis. Studies show that there is no benefit to adding electrolytes during exercise as the body does not require them to maintain this balance.

As for fluids, the body is capable of performing at a high level, even when dehydrated up to 6% or 7% of total body weight. Studies from the past 100 years show that the human body naturally dehydrates itself and then re-hydrates at meal times. The recommendations for hydration over the last couple of decades have all come from studies performed by scientist being funded by the big beverage industries. A couple decades ago, the mantra was to "drink as much as is comfortable" so as not to lose any weight during exercise. This turned out to be very dangerous as people in endurance events were drinking themselves to death, literally, by bringing on a condition called hyponatremia. The recommendation was later changed to "drink to thirst" and that is what it is today. In many cases, this is still unnecessary, depending on the length of the exertion and the air temperatures. Most people aren't going to need any fluids for anything up to about 2 hours and even after that, it depends on the individual and the temperature.

Now, race day is a different story. By adding additional carbohydrates, you assist the body in fueling itself. I do believe that gels are beneficial for races lasting longer than about an hour. I will usually do one gel at the hour mark of a HM and I do one gel every 45 minutes during a marathon. To make sure that the gel is not going to cause problems, I will set aside one or two training runs to test out the gels. I will take two along on an 17+ mile run and take them near the end, just to make sure they don't cause any gastric distress. Always practice what you are going to do on race day. Nothing new on race day.

I'll be doing the Half Hidgon Novice 2 myself, I'm starting Jan 1st, hopefully not with a hangover LOL.. good luck with your training and your marathon.