Wellington’s Te Kopahou Reserve is a place of steep hills, scrubby coastal headlands and numerous tracks. A few years ago I ran from my home, around the south coast, grinding up the 400m Tip Track climb almost to the observatory at Hawkins Hill, then down to Red Rocks and along the coast back home. Twenty kilometres, in the heat of the day, at a jog. Door to door, nearly three hours. I was shattered. And for the rest of the weekend, near useless.
I was training for a run over the Tararua Range’s 32km Southern Crossing. Despite jodphur-shaped thighs, I’ve never been a fast runner, and the race would probably take me eight hours.
So how do people train for long mountain runs? I consulted Lucky Legs, multisport legend Steve Gurney’s autobiography. During my three-hour run, I’d eaten no food. But more importantly, I’d not drunk enough water. Gurney recommended as much as one litre per hour.
The next weekend I took a 2.5-litre bladder of water and energy gels. It was difficult to drink that much water. Sipping while also trying to breathe on the punishingly steep Tip Track was more than my lungs could cope with. Instead, I drank whenever humanly possible: on the flat and downhill sections. And gagged down two sickly sweet gels. Got home slightly faster, but that was not the point.
After resting for a couple of hours, I felt fine. Good, even. Soon my energy returned and I could be a useful parent. Proper hydration, plus two gels, proved transformational. Thanks Steve.
Mountain running, unsurprisingly, requires excellent hydration. But what about tramping or climbing? How much does water, or lack of it, affect performance? Could drinking too little mean more than just becoming thirsty: could it be dangerous?
I thought back to a Mt Owen trip when my friend Darryn and I traversed the marble mountain. From the Owen River we’d tramped with full packs to Sunrise Peak, a steep climb of some 1100m, then sidled around the fissured limestone slopes of the mountain’s southern side. Although we’d drunk a litre of water at the river and carried a litre more, the blistering heat of February meant we soon ran out. Summer had parched the mountain. We found no tarns, not even a trickle. Despite the craggy magnificence of the tors, we both felt unnaturally fatigued, our blood thick. We grew increasingly tired and slow.
According to Ministry for Health advice on hydration, just a two per cent rise in blood thickness can make you feel thirsty. A five per cent increase means dehydration. We were at that level.

