The study measured respiratory droplet output of various masks and face coverings. Researchers stated that speaking through the neck gaiter caused large respiratory droplets to disperse into a multitude of smaller droplets that hang in the air longer, rendering it less effective.
Remember, we’re still in the early stages of understanding the long-term impact of wearing different types of masks, especially during exercise. There are some limits to this research study. They did not investigate breathing while exercising or nasal breathing. And, the focus of the study was to demonstrate an easy method of testing various face coverings for future research. Other factors not considered include material type, how the gaiter fits, speech patterns and head positioning.
The sample size in this study was only one person wearing the gaiter. With such a small sample size, it’s difficult to generalize these results to the larger population.
One more note on masks, beware of the training masks that claim to simulate altitude. They do not. They are “re-breathers” that offer resistance to breathing when training.