Student Research

For exercise science graduate students Joe Quackenbush and Sam Helfer, CRESE allows them to combine their interests in human performance with potentially significant real-world applications for exertions to high altitude.  

“We hope to identify a method of training the respiratory muscles that can be used by members of the military to assist their adaptation to altitudes up to 12,000 feet, while also improving several tactically important aspects of their performance, namely exercise capacity, cognitive function and night vision,” says Quackenbush.

“When a person ventures to altitude, the total atmospheric pressure is reduced,” he explains, “and as a result, there is a decrease in the pressure of oxygen in the ambient air and, thus, in the arterial blood. Due to this lower pressure, it is harder to meet the body’s oxygen needs as there is less oxygen in the blood that is delivered to tissues, cutting oxygen supply. The body undergoes a number of adaptations in an attempt to maintain its functional ability under these conditions. One of these changes involves increasing the volume and rate of breathing in an attempt to take in more oxygen.

“Imagine what happens when you boil water and the steam collects inside the pot,” he says. “The collected steam under the lid is under high pressure, meaning the water droplets that comprise the steam are close together. When you pick up the lid, the steam releases and dissipates into the outside air which is at a lower pressure. The lid on the pot is analogous to the atmosphere surrounding Earth. This atmosphere keeps the air around us at a relatively constant pressure, depending on the altitude. Oxygen particles react similarly to the particles of steam when one ventures to high altitudes. As we climb higher into the atmosphere, the oxygen particles are at a lower pressure and thus further apart, similar to when the top was lifted from the boiling pot of water. As the oxygen spreads out, we must work harder to deliver enough oxygen to all of the cells of our body. To do this, our body increases our rate of breathing so we can take in more oxygen. While we are taking in more oxygen with the increased breathing volume and rate, we are also exhaling more carbon dioxide.”

And this is where problems can occur. “In the body, carbon dioxide acts as a potent vasodilator, meaning that it allows our blood vessels to dilate or increase their diameter,” says Quackenbush. “Under conditions like those found at altitude, where we are exhaling more CO₂, our blood vessels and particularly those in our brain, contract and lower blood flow to that region. The reduced brain blood flow will have an effect on cognitive function and vision.”

The research team is simulating altitude in a hypobaric (altitude) chamber in the CRESE facility.

“To determine the physiological functions and responses to altitude and the results of the respiratory muscle training, we are using several pieces of equipment to measure specific physiological functions,” says Helfer. “First, we use an electrocardiogram (EKG) to monitor heart rate and proper/safe heart rhythms from the EKG tracings. We also use a pulse oximeter to measure the amount of oxygen in the blood (oxygen saturation), which is known to decrease as altitude increases. We also use a unique piece of equipment, a cranial oximeter, to measure the oxygen saturation that is diffused across both the left and right hemispheres of the brain tissue.

“We are also using a Transcranial Doppler which measures the velocity of the blood through the middle cerebral artery, representative of the blood flow to the cerebral cortex,” says Helfer. “The device uses ultrasound waves emitted from a probe placed on the temporal space of the skull on both the left and right side of the head to measure the left and right middle cerebral arteries. Subjects are also breathing on a mouthpiece that both collects expired gases for analysis and also samples CO₂ levels on a breath-by-breath basis known as end tidal CO₂, which is assumed to be equal to the CO2 in the blood.”

The team uses a stationary bicycle, called a cycle ergometer, to standardize exercise intensity and to accurately measure the amount of the work performed by the subjects.

Serving as mentors to the students are renowned researchers and UB School of Medicine and Biomedical Sciences faculty members David R. Pendergast, EdD, and Claes E.G. Lundgren, MD, PhD. They are both among the world’s most distinguished specialists in environmental and respiratory physiology. Pendergast serves as director of CRESE and Lundgren is one of the founders and past director.

Quackenbush and Helfer both have high praise for their mentors and the supportive CRESE staff which includes technicians Mike Fletcher, Curt Senf, Ron Okupski and Lukas Eckhardt and administrative assistant Nancy Niedermayer.

“The CRESE lab and staff as a whole has been an integral part of my education, providing me with the tools to be confident in performing future research studies and providing me the ability to apply lessons and experiences learned beyond this lab,” says Helfer.

The learning will continue as the data collection portion of the study comes to a close. Quackenbush and Helfer will then analyze and present their findings for their master’s degrees. While a report will be submitted to the study sponsor, the United States Special Operations Command (USSOCOM), which may result in respiratory muscle training being recommended to military personnel, the team hopes the study may also be of use to the general population for personal performance improvements both at sea level and altitude, as well as for potential applications in rehabilitation.