You may already be aware that the highest priority training for multi-day trips is building your pack-carrying endurance, including Back-to-Backs. But if you plan to head above 8,500 feet of elevation, you will also want to include interval training to prepare mentally and physically for what feels like “thinner air” at a higher altitude.

Interval Training Defined

By “interval training” we mean training that allows you to elevate your heart rate to the upper ends of your training zone (85-95% of your MHR, max heart rate) and then work at a lower, baseline level to recover before you go hard again. “Intervals” are repeated segments of high-intensity effort and lower-intensity recovery pieces and can be done by running up hills and jogging back down, briskly carrying a weighted pack up hills or stairs, and then walking at a normal pace back down or cycling through a set intervals program on an Elliptical trainer or step mill. You can also use apps on your phone that will direct you when to go hard and when to recover.

This technique prepares you for the challenge of working at or above the Anaerobic Threshold (AT). Be aware that you will not be able to sustain a higher level of heart rate for any substantial length of time. At high altitudes, where there is less available oxygen, you may sometimes feel like you are struggling to catch your breath. If you have trained your body to deal with such stresses at lower elevations, it is likely that you will be more comfortable with similar stresses on a high mountain.

When To Add Interval Training

For the first few months of any training program, your focus should be on increasing muscular and cardiovascular endurance first. Once you are better conditioned (i.e. after several months) and approaching the time for your goal trip, you can begin adding interval workouts. Because interval training is quite intense on the body (and requires more recovery time), we recommend starting with one interval workout per week.

How to Do Interval Training for Hiking and Mountaineering

To incorporate an interval workout into your program, schedule it on a shorter cardiovascular day, perhaps after a medium-length cardio day or the day before a  strength-training day for legs. Be sure to warm up well for several minutes to ensure increased blood flow to the large muscles in the legs and core.

For your first intervals day, you might try walking with a lightly weighted pack, or jogging up a fairly steep hill (without a pack) for 1-3 minutes, trying to get your heart rate 15-30 beats higher than your usual endurance training heart rate. Return to your starting point at a comfortable pace so the heart rate drops back to a base rate, and repeat until you have finished six complete intervals.

The next time you repeat the workout, 1) add a hill, 2) try to increase your leg turnover rate to push your heart rate higher, or 3) add <10% to your pack. Work up to 20-30 minutes of targeted intervals, and be sure to cool down and stretch following that workout.

Doing Intervals Year-round

For those people who like to be prepared to hike year-round, you can include a weekly interval to keep your body adapted to working near the anaerobic threshold. Just be aware of what your body can handle. If you sense you are 1) approaching burnout (i.e. you “just don’t feel up for it), 2) getting tired earlier in the intervals workout than usual, or 3) feeling any discomfort in your body beyond the usual muscle fatigue, you may want to allow yourself additional time to recover, in order to avoid overtraining and injury.