Without a doubt, trekking in the Peruvian Andes will allow you to see some of the most stunning beautiful landscapes in the world, bring you to remote villages with entirely unique cultures...and leave you, literally, breathless. All this beauty surrounding you is roughly somewhere between 9,000 and 16,000ft. above sea level; and chances are you arrived from some place significantly lower, and richer in oxygen. When you arrive at the airport in Cusco, you are already at an altitude of 11,200ft, and if you've planned a multi-day trek for your trip you're going to be climbing even higher. For example:
-On Day 2 of the 4 day Classic Inca Trail you will climb to 4,200mt/13,780ft at Warmiwanusca Pass.
-Also on Day 2 of the 5 or 6 day Apu Salkantay to Machu Picchu trek you will reach 4,750mt/15,585ft at Portachuelo Pass
-Again, on Day 2 (what is it with day 2?) of the Lares to Machu Picchu trek you will reach 4,300mt/14,107ft at Condor Pass
Even if you decide to skip the trekking, Machu Picchu is still at an altitude of approx 8,000ft.
You can't expect trekking at this altitude to feel the same as a hike in the local hills, but you can prepare - and even if your trip to Peru is several months away, you should start NOW.
I had two distinct advantages on my side when I left for Peru: I was living at 4,000ft in Montana, and in a town that has over 70 miles of trail for running, hiking, and mountain biking accessible from my back door (mad props to my friends at the Prickly Pear Land Trust for that!). 4,000ft may not seem like much compared to the altitudes mentioned earlier, but it's a start - and it had been a great summer for mountain biking the big routes in southwestern Montana. And still, the altitude was a force to be reckoned with when I arrived in Cusco and wanted to get up into the hills. My best advice to prepare for the altitude is to begin exercising regularly (consult your doctor if this is a new regimen or if you've experienced health issues in the past) , and start pushing beyond your comfort zone little by little. The reduced oxygen levels at altitude will make a noticeable difference in your breathing and elevate your heart rate; it's a good idea to be used to this sensation before you're staring up at Portachuelo Pass. If you have access to hiking trails, load up a pack and pick the steeper route. If, like most people in the Northern Hemisphere this winter, you're gym-bound, try the Stairmaster or walking on an elevated treadmill. An eliptical machine or cycling probably won't work the same muscles you're going to need for extended uphill trekking. Another tip is to pick a reputable tour operator to guide you; if you pay bargain basement prices you may end up being rushed along the trail and hiking greater distances per day in order to cut operating costs - leaving you exhausted and, most likely, more than a little annoyed.
The altitude on these treks is a challenge; but you may not even notice it when you're surrounded by towering snow-capped peaks, pristine mountain lakes, and lush green forests and valleys. And there's good news: many tour operators in Cusco now offer altitude-adjustment programs that include day hikes to some of the local Inca archeological sites. Regardless of how you prepare, be certain to have some miles logged on your pedometer and rest days built in to your itinerary prior to starting your trek when you arrive in the Peruvian Andes in order to make your experience memorable for all the right reasons.
(For tips on dealing with altitude sickness check out this site.