When we hike the Long Trail, bike on Acadia’s carriage paths beneath blazing foliage, or kayak a favorite pristine lake out in the wilds, we enjoy the scenic views and feel the hard work our arms and legs are doing. But what about our breathing? How many of us think about the pattern of inhales and exhales we take when we recreate?

It’s OK if we don’t—most of the time. Breathing should fall into a natural rhythm determined by the intensity of your activity, according to Heather Nettle, an exercise physiologist with Cleveland Clinic Sports Health and Orthopaedic Rehabilitation. There are a few exceptions. In strength training, for instance, you typically inhale through the nose in recovery and exhale through the mouth during the lift.

DOs AND DONT's Breathing in through the mouth allows the most efficient air flow to the lungs because more air goes in with each breath. Some people believe that breathing through the nose is best because you can filter out dust particles and flying insects, as well as warm the air in cold weather before it hits your lungs, but many people cannot breathe efficiently that way, especially those with asthma, sinus problems, allergies, or a deviated septum. And during hard exercise, it often becomes automatic to open your mouth in an effort to get oxygen more quickly.

Philip S. Clifford, professor of anesthesiology and physiology at Medical College of Wisconsin, points out that for activities like rowing there is an advantage to coordinating breathing and stroke, namely exhaling during the work (the stroke) and inhaling on recovery, as with weights. “This seems to be less important in exercise that uses only the muscles of the lower body, like biking and hiking, and may be due to the fact that during rowing, the muscles of the ribcage are being used both for breathing and movement,” he says.

While walking, hiking, and biking, many people easily adopt a breathing rhythm that corresponds to their cadence, which works well. A mountain biker, for example, might take one breath in and one out for every two or three pedal strokes. Nettle also emphasizes that good posture can help unburden the lungs. Hunching too low over the bike can cause compression and impinge on your lungs’ ability to fully expand, as can cinching too tightly the shoulder straps or hip belt on your backpack.

RED-LINING If, when exercising, you are gasping for air or hunching over to try to “rest” while you are still moving, you have reached your anaerobic threshold—the exertion point where you are breathing too heavily or inefficiently and need to back off. Breathing under these circumstances becomes shallow and further exacerbates the situation. The oxygen level in your blood drops because it can no longer be absorbed effectively, and your muscles begin to accumulate lactic acid.

“You’ll get that muscle burn,” says Nettle, and be unable to maintain constant breathing or level of intensity. For a conditioned athlete, it is not necessarily bad to approach this point, as it “ups” aerobic capacity over time. However, even for the veteran hiker or biker, when muscle burn occurs, take a break and then resume a less strenuous pace to avoid “bonking” again during your trip.

LUNG CONDITIONING If you exercise regularly but have reached a plateau where you no longer feel challenged, Nettle suggests incorporating fast-slow interval training. This technique can be employed during hiking, biking, swimming, even walking, and it will help build cardiovascular endurance, which will lead to easier, more consistent breathing when you tackle that next 4,000-footer. Try a faster jogging pace from one street light pole to the next, and then slow your pace until you reach the next pole. On your bike, pump hard for a quarter mile; slow down for the next quarter mile.

Aerobic exercise may be more effective at building lung capacity when compared to targeted breathing exercises. “There has been some suggestion from outdoor enthusiasts that…inhaling and exhaling quickly for three or four breaths and then forcefully exhaling all air once a day will improve tolerance for altitude, although there isn’t considerable evidence to support this,” says Nettle. Clifford agrees, saying that while you can strengthen  respiratory muscles by breathing against resistance (like pursing your lips while exhaling forcefully), studies do not show this improves athletic performance.