Altitude, heat and the hike you can actually do

Two things quietly ruin more park days than anything else: going high too fast, and going out in heat with the wrong plan. Both are predictable and both are avoidable.

Altitude

Above roughly 2,400 metres, or 8,000 feet, most people feel it: headache, breathlessness, poor sleep, no appetite. That is ordinary altitude sickness and it usually passes in a day or two. What matters is knowing when it is not ordinary.

• Climb high, sleep low. Your sleeping elevation is what your body adapts to, not the highest point you touched.
• Give yourself a night at intermediate elevation before a big day. Denver before Rocky Mountain is exactly this.
• Drink much more water than usual. Dry air at altitude takes moisture with every breath.
• Skip alcohol on the first night. One drink at 2,500 metres behaves like several at sea level.
• Descend if it gets worse. Confusion, loss of coordination, or breathlessness at rest are serious and mean go down now, not in the morning. Descent is the only reliable treatment.

Heat

Desert parks kill people who were only going for a short walk. The pattern is always the same: an easy walk out, a much harder walk back, in rising heat, with not enough water.

• Carry at least four litres per person for a full desert day, and more if there is climbing.
• Hike at dawn and dusk, and treat the middle of the day as rest time. This is not weakness, it is what locals do.
• Rock radiates. Slickrock and canyon walls can run 20 degrees Celsius hotter than the air temperature.
• Salt matters as much as water. Drinking litres without eating leads to its own problems.
• Turn around at a time, not at a place. Decide before you set out what time you turn back regardless of how close the summit looks.

Judging a trail honestly

Distance is the least useful number in a trail description. Elevation gain, exposure and surface matter more. A useful rule of thumb is roughly one hour per 4 kilometres of flat walking, plus an extra hour per 600 metres of climbing, then add time for altitude, heat, scrambling and photographs. If that total means finishing after dark, it is a different hike.

The short list that prevents most rescues

• Tell someone your route and your expected return time.
• Carry a headtorch even on a day walk. Being benighted without light is how a delay becomes an emergency.
• Take more water and one more warm layer than the forecast suggests.
• Download the map offline. Coverage in canyons and valleys is unreliable.
• Turn around when you said you would.