Elevation masks are devices worn over the mouth and nose during exercise that restrict airflow using a series of valves. They are marketed to athletes claiming to simulate the physiological benefits of high-altitude training, promising improved stamina and endurance by making the respiratory system work harder. This article explores the scientific evidence behind these claims.
Why They Do Not Simulate Altitude
The physiological benefits of true altitude training stem from a decrease in the partial pressure of oxygen in the air. This lack of available oxygen, known as systemic hypoxia, forces the body to adapt by producing more erythropoietin (EPO), which in turn increases the number of red blood cells to enhance oxygen-carrying capacity.
Elevation masks, however, do not change the partial pressure of oxygen in the air being inhaled. The air inside the mask retains the same oxygen concentration, approximately 20.9% at sea level, as the surrounding environment. The masks work only by restricting the volume of air, or ventilation, that can move in and out of the lungs. Because the masks do not create a true hypoxic environment, studies consistently show they fail to trigger the crucial hematological adaptations, such as an increase in hemoglobin or red blood cell count, associated with altitude training.
The True Mechanism: Respiratory Muscle Training
The actual effect of the elevation mask is to function as resistance training for the breathing muscles. The restricted airflow forces the primary muscles of respiration—the diaphragm and the intercostal muscles—to contract with greater force. This mechanism is defined as Respiratory Muscle Training (RMT).
Over time, this increased workload strengthens the respiratory musculature, similar to how lifting weights strengthens skeletal muscles. A stronger diaphragm is beneficial because respiratory muscles can fatigue during intense or prolonged exercise. When the diaphragm fatigues, the body may divert blood flow away from the working limbs to supply the breathing muscles, potentially accelerating overall muscle fatigue. Strengthening these muscles helps delay this diversion, preserving oxygen delivery to the legs and arms during a workout.
Scientific Findings on Performance Improvement
VO2 Max and General Performance
Research on the masks’ effect on maximal oxygen uptake (VO2 Max) has yielded mixed results. Some analyses indicate that improvements in VO2 Max seen in mask users are comparable to improvements in control groups performing the same training without a mask. This suggests the training itself is responsible for the gain in overall oxygen capacity.
Endurance Markers
The evidence is more promising for markers directly linked to endurance. Multiple studies show that training with an elevation mask can lead to significant improvements in the Ventilatory Threshold (VT) and the Respiratory Compensation Threshold (RCT). These thresholds represent the maximum exercise intensity an athlete can sustain before the body begins to rely heavily on anaerobic metabolism and fatigue sets in. Improvements in these specific endurance markers suggest the strengthened respiratory muscles allow for more efficient breathing and delayed fatigue during sustained effort.
For instance, one study found that a mask group showed significant improvements in power output at both the Ventilatory Threshold and the Respiratory Compensation Threshold, while the control group did not. This indicates the mask’s RMT benefit can enhance specific endurance capabilities beyond what is achieved with standard training alone. While generally safe for healthy individuals, people with pre-existing respiratory or cardiovascular conditions should consult a healthcare provider before using the masks.