|The masks are no alternative for altitude training - that's quite certain.|
In the aforementioned study, the researchers from Texas A&M tried to figure out whether so-called "elevation training masks" (ETMs) would boost the VO2max of male Reserve Officers Training Corps (ROTC) cadets. For this purpose, Warren et al. recruited fourteen male ROTC cadets (age 20.00 ± 1.8 yrs, height 174.35 cm ± 3.1 cm, weight 76.75 kg ± 11.09 kg, body fat 13.88% ± 4.62%) who were then randomly assigned to either the control or experimental group, respectively. All participants did the standard ROTC program, the authors describe as follows:
"In conjunction with each training session, there was a warm-up and cool-down period. The first training session consisted of one moderate-distance run that was approximately 2 miles and was performed in an interval style with 60 seconds of slow jogging followed by a 10 second sprint. The second day had participants rotate through an 8-station body weight circuit. The longest run was always on the third training day, which required the cadets to run approximately 4 miles at a steady pace" (Warren. 2017).The training period of the study was seven weeks. Each subject participating 3 days per week. Over the course of the seven-week training sequence, the breathing resistance on the "elevation mask" was increased from a resistance that was meant to simulate 3,000 feet above sea level in 3,000 feet intervals. Accordingly, the resistance at the beginning of week 4, after which no further increases were undertaken, was set to what the producers of the masks claim would simulate training at 12,000 feet (for Europeans: that's 3657.6 meters) above sea level.
|Figure 1: Changes in VO2Max (left) for each subject and abs. VO2Max pre- vs. post data for all subjects (Warren 2017).|
If there's a chance that the masks are more than a fashion gimmick, ...
this has to be a 'side effect' of a potential training effect the masks could have on your inspiratory muscle (learn more about inspiratory muscle training aka "IMT"). Even though, the evidence that the musculature you use to suck in the air is a bottleneck for athletic performance is ambiguous and studies such as William et al. (2002) or Inbar et al. who had their well-trained endurance athletes use a special threshold inspiratory muscle trainer for 0.5 h x d(-1) six times a week for 10 weeks found no performance increases, in spite of significant increases in inspiratory muscle performance, there are also studies that suggest beneficial effects on exercise performance in noobs and pro-athletes:
- Chatham, et al. who report reduced levels of breathlessness, and increase in predicted (not measured) VO2 max in healthy, but untrained subjects after 10 weeks and 30 Tests of Incremental Respiratory Endurance (TIRE) set at 80% of peak.
- Volianitis et al. 2001 who found an increase in the distance those of the 14 female competitive rowers who had been randomly assigned to the active treatment covered in a 5 min all-out rowing test, as well as an increase in time-trial performance after 11 weeks of twice daily inspiratory muscle training on a specifically designed device.
- Romer et al. 2002 who observed that inspiratory muscle training attenuates the perceptual response to maximal incremental exercise and a marginally higher increase in 20 and 40km time-trial performance in 16 healthy trained male road cyclists.
- Enright et al. 2006 who observed non-specified (full text not available) increases "exercise capacity in people who are healthy", but previously untrained in response to an 8-week program of IMT set at 80% of maximal effort.
- Chatham, K., et al. "Inspiratory muscle training improves shuttle run performance in healthy subjects." Physiotherapy 85.12 (1999): 676-683.
- Enright, Stephanie J., et al. "Effect of high-intensity inspiratory muscle training on lung volumes, diaphragm thickness, and exercise capacity in subjects who are healthy." Physical therapy 86.3 (2006): 345.
- Inbar, Omri, et al. "Specific inspiratory muscle training in well-trained endurance athletes." Medicine and Science in Sports and Exercise 32.7 (2000): 1233-1237.
- Lauren, Bryan, et al. "Physiological Change Through Aerobic Exercise Under Hypoxic Conditions With An Elevation Mask." (2015).
- Romer, Lee M., Alison K. McConnell, and David A. Jones. "Effects of inspiratory muscle training on time-trial performance in trained cyclists." Journal of sports sciences 20.7 (2002): 547-590.
- Volianitis, Stefanos, et al. "Inspiratory muscle training improves rowing performance." (2001).
- Warren, Brian G., Frank Spaniol, and Randy Bonnette. "The effects of an elevation training mask on VO2Max of male reserve officers training corps cadets." International Journal of Exercise Science 10.1 (2017): 4.
- Williams, James S., et al. "Inspiratory muscle training fails to improve endurance capacity in athletes." Medicine and Science in Sports and Exercise 34.7 (2002): 1194-1198.