I am training for my first marathon (Beachy Head) and after a bit of advice please.  My longest run to date has been 16 miles and I feel pretty rubbish afterwards (don't feel like eating and feel dehydrated with a bit of a bad head).  I drink loads prior to training, take a camel pack with me, stop to top it up and have a swig of a sports drink and take lucozade dextroise tablets as I run with water.  Am I missing a trick somewhere?  I find drinking banana milk helps me.  All advice gratefully received!

When you get back you have a "golden window" of about an hour to take carbs and protein on board for maximum effect.

Milkshake is fine but you probably need more than that as you will have burned about 1400 calories. I have 500ml of Rego (recovery drink) made with milk chilling in the fridge ready for my return. I have noticed that when I take it my muscles recover much more quickly than when I don't.

You could have jam sandwich; small pasta salad anything with a 4:1 ratio of carbs to protein - and lots of fluid. 

The worst thing you can do is ignore the symptoms because that just slows your recovery and makes the next run more difficult than it need be.

I'd whole-heartedly echo what the last few posters have said, although I might reduce Mike's 'Golden Window' to around 20 minutes.

You do seem to be taking in rather a lot of fluid, and perhaps not enough carbs. Basically the rule is carbs before and during exercise, protein after. Carbs to fuel the muscles and protein to repair them.

When do you do your long runs? If you're going out before breakfast you may be lacking glycogen stores to begin with.

I love a milkshake after a long run - worth letting a few bananas get over-ripe, to whizz up with milk, wheatgerm, and whatever berries etc you fancy or have lying around! Failing that an off-the-shelf banana or chocolate milk shake is good, and the 'For Goodness Shakes!' ones are very good. Then it's into the shower, and a proper meal ASAP.

As Kate says, the headache might not necessarily be a sign of dehydration, and the best indicator is pee colour (and smell!). It's even possible that you could be inducing hyponatremia - which is kind of the opposite of dehydration but has virtually the same symptoms.

Best of luck with your training and the marathon, Portman - hope it goes really well.

There is new edivence that milk contains more of the 'essential' salts and other minerals than the post performance drinks.

My long runs from 18 miles upwards and significant distance races (10k and above) I always get the porridge down me 2 - 3 hours before running then most importantly post run is a large glass of choccy milk mixed with a serving of Whey protein powder within 20 minutes (I might even treat myself to a Mars bar if I done really well), then during the remainder of the day regular sips of water to staive off dehydration headaches and nausea.

Mind you the evidence may have been submitted by the Milk Marketing Board, I don't know...but again I am cynical on some research.